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week 4 - Neurobiology and Behavior

Paul Grobstein's picture

Lots of interesting thoughts last week about the I-function and related matters. Curious to see what is on peoples' minds this week as we talk about neurons ...

Anonymous's picture

Autism, Color, and Emotions

A friend called me because I am an artist, asking me how I perceive colors related to emotions. She is working with an Autistic Child teaching him to use color to describe his emotions. If you have any thoughts on this please share.

alexa09's picture

the brain/mind

Is there really an I-function? Do we really have any say in our actions? What is the definition of free will? According to Mark Hallett, a researcher at the National Institute of Neurological Disorders and Stroke, "Free will does exist, but it's a perception, not a power or a driving force. People experience free will. They have the sense they are free.”

But the perception of being free does not necessary mean that it exists. According to Benjamin Libet’s research during the 1970s, Dr. Libet found that brain signals associated with random motions (such as pressing a button or flicking a finger) occurred half a second before the subject was conscious of deciding to make them. This means the brain perceives motion before it makes the decision to make it. From personal experience, I have experienced times when I make a decision without consciously realizing I am making the decision. When I was in fifth grade I went to an amusement park. There were people miming and a mime came up to a little boy and blew on a deflated balloon. The mime did this several times, before trying it to me; I blew on the deflated balloon and the balloon became inflated. Afterwards I realized I did not know when I made the decision to blow on the balloon; now I can only assume that my unconscious brain made the decision first before my conscious brain knew.

Shayna or Sheness Israel's picture

You Are Responsible, Right?

Thursday we spoke about neurons creating actions potentionals internally (without external imput) due to particular canals allowing certain concentration gradients to happen. At first, I was a little disappointed because I expected some psychic freakiness to cause neurons to create outputs with no imputs. Also, neurons can continously generate these action potentials as long as specific valves are opened that allow sodium in.

I actually got happy, because of how much power that gives, this mind thing that must control it. (I would be pretty upset if this mind thing is also not something freaky and mystical.) Something must stop these action potentials. But I guess there can be other neurons that cause these special valves to close as well.

If all this is the case then maybe action is beyond our rational/moral/cultural control. This doesn't hold water. Information changes the pattern of matter in the neuron, so you can stop and close the valves if you receive information and inside our society, we are receiving information all the time. So the question becomes how do we sort through what information we will use to stop or start action potentials?

I am just waiting for the mystical freaky part of neurobiology to happen. So, Paul, bring on the spooky!

michelle's picture

I loved reading Shayna's

I loved reading Shayna's response to action potentials and neurons. I've taken basic biology and biochemistry and am familiar with action potentials, neurotransmitters and the whole jazz. I understand that there are a number of feedback regulation mechanisms in the body that control the firing of action potentials. I love how Shayna gave the system a mind in order to control the system. I also love how she stretched the idea to describe societal influence on our behavior, treating the information as ions flowing across our membranes.

It allowed me to realize how much scientists miss out on simply by neglecting to explore other perspectives. Shayna’s first impression of neurotransmission clearly exemplified her creativity, creativity that I lack, but thoroughly appreciate in others. I never knew it to be possible to take such a concrete, scientific topic and blow it into a more universal context.
What we fostered in this course is variability, what we didn’t explore is why? What allows for some to be creative and others to be athletic? I know a huge portion is due to our genetic makeup, but how much can other factors influence our personality traits? I did some exploring on the web and found that there is a whole sub-discipline of psychology dedicated to understanding the formation of personality traits and the topic could be a course within itself. Therefore, I narrowed my focus a little bit and found an interesting article describing how personality traits could be linked to facial features. ( In the study, the faces of different couples were shown to participants who didn’t know which individuals were linked. The participants were asked to predict the attractiveness, age, and personality of the individuals and the study showed that couples were ranked to have similar ages, personalities and attractiveness scores. This study was aimed at understanding why a number of couples look alike, especially after dating for long periods of time. Hmm…I wonder if this study could be applied to owners and their dogs because I tend to see a lot of owners to look and act a lot like their dogs.

urbrainondrugs's picture

W/F ired Together

In class we talke about neurons all being the same. They all have the same basic structure and they carry out the same basic function of carrying signals across the body and brain. The difference between them are the networking and the patterns at which they fire. If this is so, then like-neurons, would be those that fire at a similar time all the time. For epilepsy patients, during an epileptic seizure, the brain fires action potentials at an unhealthy rate. For most, the same areas of the brain are affected and the patient will usually suffer the same symptoms with each occurence. Does this mean that the neurons that are being fired during a seizure are all like neurons? And if so, out of adaptation, will these like neurons link together in a synaptic network in order to become more efficient over time? I think this could be an interesting idea in ways our bodies can work against us. The nervous systme would be facilitating future seizures.

Lauren Poon's picture

All or None

Action potentials have been described as “all or none.” The input has to reach a specific threshold before the neuron fires. Above this point, the intensity of the signal does not matter. The neuron will send the same signal regardless of whether or not the peak is higher than the necessary threshold. That talks about the “all” part of action potentials, but what about the “none” part? Are there some inputs that never reach action potential because they’re below the threshold point? Does a person never feel these inputs? I suppose sensory inputs that fall below the threshold point prevent us from being super sensitive. For example, every single minute piece of dust that brushes against our skin does not cause us excruciating pain. It seems that the “none” part of action potentials protects us from unimportant or insignificant stimuli.

Anonymous's picture

Aquired Tastes

I've been thinking about sensory neurons as well as the way we sense different inputs such as sound and color through different pathways. I also have been wondering about the concept of aquiring tastes. Most of us have probably aquired a taste for something in our lives. A couple of examples might be coffee or wine. When I was a child I hated the taste of coffee but I enjoy it now because I've "aquired" a taste for it. How do we aquire tastes? Maybe there is a change in the signal pathway through our neurons. When I did not like the taste of coffee the activated signal pathway might have been different than the one I experience now. This could be due to the activation of new sensory neurons on the tongue or maybe the enhancement or deterioration of taste sensory neurons over time. I would be curious to learn exactly how one persons neurons differ from a time when they do not like the taste of something to a time when they do like it. Is the change a gradual one or does it occur very quickly before we can realize that it happened. What might the physical or chemical changes be in sensory neurons that cause the change of displeasure to pleasure?

On a somewhat related note it might be interesting to see the differences between the signal pathways in sensory neurons in a person who enjoys the taste of one thing and those in someone who does not enjoy that thing.

Sasha's picture


Through discussions of neurons and receptors we learned that action potentials are the same throughout the brain, but are interpreted differently in different areas and receptors. This led us to wonder- “how much of reality are we perceptive to? Only that for which we have receptors?”

 In an article in last weeks New Yorker (Two Heads) similar questions were raised. The article was a profile of Patricia and Paul Churchland, philosophy professors who focus on Neuroscience and the “mind-body problem”. The most interesting point in the article was the idea that even if somehow at this time we were to suddenly come across the answer to what the mind is, perhaps we wouldn’t even know what to make of the answer because neuroscience is not far enough along. This leads me to wonder if we ever really can or will be far enough along- what kind of receptors are required in the human brain to understand the deep inner workings of the brain itself? Do we have those receptors- or will evolution perhaps lead to a development of such receptors? Or will an understanding of mind and consciousness remain in another reality that we are not open to- like high pitches heard by dogs and horses- we know it’s there, but we can’t really perceive it.

biophile's picture

Systems of thought

Quite a few people have already posted thoughts similar to mine, but I'll throw out my ponderings as well. As someone has already said, it's strange to think that thoughts can produce action potentials and vice versa. I've always been amazed by the concept that the mere travel of potassium and sodium ions across a membrane could have such profound and various effects. On the scale of a single neuron, it seems preposterous. This relatively simple exchange repeated so very many times and these simple units structured in many different configurations can lead to action and even consciousness... It's a sobering thought.

Secondly, the question of what is truly our external reality is both a very worthwhile question and one that will never be answered. Because we're not operating using nervous systems with structures similar to those of other organisms such as sharks and butterflies, we'll never intuitively understand how they experience the world... Science and technology are amazing because they allow us to do and see things we wouldn't be able to conceive of otherwise. In a way, science has greatly enhanced our creativity by showing us that the way we sense things is not necessarily the only way to sense them, that there exist worlds upon worlds which we cannot experience.

On a tangent, it's interesting to note how some people (myself included at times) talk about evolution as if it gave us the short end of the stick, as if it were a goal-oriented process. We talk about shortcomings and advantages that we have as if natural selection kept tally marks of them, trying to keep them balanced. Evolution isn't an entirely logical process, even though I believe there is more behind it than the passive accumulation of some characteristics.

In any case, it's good food for thought. I'm sure that if we were able to sense electrical fields instead of smell, we would ponder what scent would be like before moving on to another exercise in philosophy. Unfortunately, the I function is the one thing that we can never escape (unless we're talking about meditation, but that's a different discussion altogether). We're always wondering what it would be like to be someone else, what it would be like to be of the opposite sex, what it would be like to be part of another culture... It would be amazing to escape ourselves for just a bit and to view our own nervous systems as outsiders and to experience other realities our own brains are blocked from. We can't truly understand our own nervous systems because we're subject to their limitations and we can't see outside of them; we can't truly understand the nervous systems of other organisms (even of other humans) because we can't get into them. It's a catch-22.

eshuster's picture

Sound, Beethoven, and Receptors

I want to talk about sound, vibrations and touch. In class we spoke about how humans cannot sense infrared because we do not have these receptors or we cannot feel magnetic fields because we lack these sensors as well. It brings up the question of sound? As the saying goes, if a tree falls and no one is there to hear it does it really make a sound? Well I want to ask my own question. If a tree falls and only a deaf man is present does the tree make a sound? Well, if sound is considered sound only if someone has heard it than in both cases the tree has not made a sound. However, if sound is considered a wave that vibrates from the ground as the tree falls then a sound was created in both instances. What about the deaf man? Can he hear the sound? If one takes a look at these two questions initially, the answer is clear, the deaf man cannot hear. But, if you think of sound as a vibration than why can’t the man feel the vibration? It’s as though I was at a concert, I can feel sound vibration if I’m standing close enough to the stage. The base is making vibrations that shake the stage and I don’t need to have proper hearing to feel these sound vibrations.

Another question posed is, if I couldn’t hear the sound and only felt the vibrations could I interpret what exactly I would hear if I weren’t deaf? Meaning would the music have been interpreted the same was through the vibrations I felt as opposed to the vibrations I heard? This brings up an interesting point, what about Beethoven? He became deaf in life and starting feeling the vibrations of the music to create his symphonies. He didn’t have sound receptors but how could he interpret what he felt into what it would sound like? Would his music have been the same if he wouldn’t have gone death? Its also interesting to think about what he thought his music sounded like and what it sounds like to someone who can hear properly? Is it the same? Are there any variations? If Beethoven didn’t need sound receptors to hear the music do we not need sound receptors to hear music? Do we have sound vibration receptors throughout our body that we, non deaf individuals, ignore? Maybe, we have different receptors on our body that aid our interpretation of sound but aren’t as pronounced until we lose our sense of hearing. These questions interest me a great deal. If this is the case, is it possible that humans have some kind of receptors for infrared or magnetic fields that aren’t pronounced in our bodies unlike fish and birds? What if one day we find these receptors? If we find them are they active or could they have mutated to an inactive form? These questions came up as I thought about Tuesday’s lecture.


James Damascus's picture


I dont think Beethoven would have been a particularly good composer if he was death. He was, however, at one time not deaf, and could probably imagine what his music would sound like, given that there was not a deficiency in the region of his brain associated with sound processing (I'm not familiar with his particular condition, but I imagine it was a problem with nerve damage, or with his malleus, incus or stapes). What this means is that either nerve damage prevented the proper transmission of action potentials, or that damage to his ears resulted in pressure waves not being converted/passed all the way to the organ of corti/stereocilia (these generate electrical signals/action potentials that travel to processing regions of the brain). When considering musical composition, it should be understand that the activity is not done completely by trial and error- all composers manipulate certain conventions when writing music (pentatonic music will sound oriental, minor keys will sound darker than major keys-- there are much more complex rules than these, but this is to give a basic idea), so Beethoven was not professionally crippled by deafness. There is also a difference between pressure receptors and sound, as you understand it. Sound is the product of your ears' converting pressure waves to electrical signals that travel to your brain, and that, when processed, are understood as sound. Hope that  helps.JD

clin's picture


The way neuorns work with the brain and everything is extremely interesting to me, however, what happens to the neurons of people who have agnosia? I know there are different types such as visual or prosopagnosia, but what exactly is missing in their brain that disable the neurons from travelling to and from? Is it ever curable?

Liz S's picture

axonal regrowth

Just this past week I read an article for my senior seminar that relates to our talk on neural. The paper, entitled “Possible axonal regrowth in late recovery from the minimally conscious state” explores neuronal sprouting in the brains of two individuals who recovered (though not fully) years after going into a MCS.


For background, MCS is basically a slight step above persistent vegetative state. People in a MCS exhibit deliberate behavior, though it is often hard to distinguish between MCS and PVS.


I find it fascinating that the axonal regrowth can occur in the brains of people in a MCS. The fact that the brain can compensate/recover (even partially) after severe brain-injury is fascinating. The study suggests that, perhaps, this axonal regrowth leads to late recovery.” If this is in fact true, it makes me wonder how some MCS patients can sprout neurons and others never recover. I would assume it has to do with the type of brain injury that initially occurs, but what else affects axonal regrowth? 

James Damascus's picture

The Prefrontal Cortex, Abstract Thought and Executive Control

I was reading through a neuroscience textbook this past weekend as well as some articles, and found an interesting article concerning the prefrontal cortex and abstract thought:                                                                                                                                                                                                                             The article describes a 2001 study performed at MIT concerning pattern recognition and abstract thought. The study, in which monkeys apply rules about ‘same’ and ‘different’ images, shows that the prefrontal cortex -- the part of the brain directly behind the eyes -- works on the abstract assignment rather than simply recalling the pictures. In other words, the prefrontal cortex is involved in figuring out the rules of the “same/different” activity, rather than the simple performance of the activity. What is innovative about this approach to brain research is that it deals with abstract patterning and recognition, whereas traditional studies have focused on structures responsible for performing specific tasks, such as moving muscles or image recognition                                                                                    The Study:                                                                                                                                    Over a period of nine months, the researchers trained a group of monkeys to identify whether hundreds of different pictures were the same or different images. By recording signals from neurons in the prefrontal cortex of the monkeys as they performed cognitive processes, the scientists monitored the regions associated with “holding information in mind”, a requisite ability for information processing and thinking.                                                                                                                                                                                                                                                                                                                                                      The monkeys were trained to pull a joystick if a picture was the same as the one shown before. At other times, the monkeys were required to pull the lever to identify different images. The monkeys could apply the rule to pictures they had never seen before, showing that they were dealing with abstractions. By the end of the nine month period, the monkeys were able to respond instantly to the rule and were right more than 85 percent of the time.                                                                                                                                                                                                                                                                                                                 In studies of monkeys and humans with damage to the prefrontal cortex, researchers have found many of the same cognitive problems seen in schizophrenic patients. Among them is what is widely believed to be a disorder of working memory, which allows you to keep several pieces of information in mind simultaneously.  Abnormal functioning of the prefrontal cortex is implicated in schizophrenia, attention deficit disorder, obsessive-compulsive disorder and other diseases.                                                                                                                                                                                                                                                                              Why This Should Be interesting To Us:                                                                                                                                                                                                                                                                                                                                          The aim of this study is to gain some insight into what we’ve been referring to in class as the “I function” (the article uses the phrase “executive or cognitive control”). What this study suggests is that, although we know very little about abstract thought and its analogues, the responsible neurons are physiologically situated in the prefrontal cortex.  While there are certainly limitations to this kind of research, and, granted, we may never fully understand the physiological analogues associated with abstract thought and executive control, the investigative process is itself immeasurably valuable. If all aspects of human experience (philosophy, art, weapons of mass destruction) are byproducts of abstract thought, we have much to gain from neurobiological research.

AnnaM's picture

Neuron Patterns and Autism

Learning about how specialized all of our neurons are and how that may alter perceptions of the world got me thinking...

One symptom often associated with autism is hypersensitivity to sensory input; an autistic person may react strongly to stimuli like high-pitched noises or fluorescent lights. In other words, their sensory neurons may function differently than those of non-autistic people. Maybe they can pick up certain stimuli that non-autistic people can't perceive, or fail to notice. Already an interesting possibility.

But the more interesting qusetion here is whether symptoms like this sensory sensitivity are detrimental and should be "undone" with behavioral modification, or if they're simply a different way of seeing the world. Within the autism community, there's tremendous controversy about this topic. Some organizations, like Cure Autism Now, would say that these differences can lead to autistic people being stigmatized or unable to function in the world; they support research into funding a "cure" for the condition. But other groups claim that autism is just a difference in brain functioning, that autistic people shouldn't be faulted for perceiving the world in entirely different ways and don't need to be "cured." They sometimes use the word "neurotypical" for describing people who do not have autism.


I'm torn as to what to think about this controversy. On one hand, I entirely support the idea that everyone's brain works differently, and that autistic people may be able to offer a lot of insight. (Really, when you come down to it, who can "cure" a difference in neuron functioning?) On the other hand though, I really don't like the term "neurotypical." Since everyone has 10^12 neurons and counting, no one's neurons are "typical;" autistic neurons are just different in specific ways.

Meera Seth's picture

Do Blind People Dream?

The short answer to this question is, in fact, yes.

A relatively recent study conducted by scientists at the University of California, Santa Cruz has built on this information, providing interesting details to this phenomenon. They took a sample of 372 dreams from fifteen blind individuals, resulting in two independent analyses.

For the first analysis, a particular kind of software program created for the purpose of working with dream narratives was used to register the presence of the five senses in the dreams. With this equipment, it became clear that those individuals who had been blind from birth or very early in childhood had no visual imagery whatsoever, however did yield a high percentage of taste, smell, and touch references.

The second analysis revealed that according to several coding categories, the dreams included a high percentage of locomotion- and transportation-related dreams. Both the presence of sensory references and movement in these dreams are apparently evidence for the link between a dream's subject matter and conscious thought.

JaymElaine's picture

The Blind Dream; This is Fascinating!

Wow....I actually found this to be quite interesting. Blind people dreaming; that truly is ground-breaking. I suppose what fascinates me so much about this is that we are taught as children certain things. We are taught the alphabet, our colors, morals, what a bus looks like, I mean everything. I bet you that most, if not all, of that learning was acquired via sight. We know that things exist because not only were we taught them, we can see them (well most things, and let us not include religion...that's a whole different conversation!) So, how is it that the blind can dream things that were not seen before? Unless the imagination takes you a lot farther than we can truly imagine, I continue to be stumped by this very question. For them to be able to dream up objects, everday activities, and other things amazes me. I can attest to the blind having dreams. My cousin is blind, and when I asked him about his dreams, he told me that he dreams a lot about different things, and in his dreams he "sees" things; he visualizes objects and day-to-day routines, and the average extraordinary dreams that we all have from time-to-time.  I do hope that these researchers continue to explore the world, the mind, and the dreams of the blind, for they are quite interesting it seems.

Jayme E. Hopkins, '08

Cayla McNally's picture


It's still really hard for me to get my mind around the concept that everything that occurs around me is interpreted through my brain and mind. I say both brain and mind because the neurons in the brain have to receive the stimulation that occurs to one of my senses, and my mind interjects previous experiences to further interpret what happens. A good example of the vastness of the capabilities of the brain is the myriad of colors the eye can perceive at the same time. The amount of shade variation that the eye can see is astounding, and equally interesting is the differences that occur between the way different people see the same colors. This is something that occurs everyday, without the majority of us being aware of this, and it's just one of the hundreds of processes that happen like that every day.

x's picture

Chocolate is Good for your Brain

Well, maybe. An article in the Washington Post health section discussed how "a nice cup of the right kind of cocoa could hold the promise of promoting brain function as people age." Having a certain kind of cocoa (flavanol) added to your diet (or at least to the diet of test mice) positively impacts the hippocampus, and thus allows further memory retention. Lower blood pressure and dilation of the arteries have also been associated with the regular consumption of flavanol.

This sounds like great news, especially for chocolate lovers like myself. The article is careful to say that this doesn't mean we should start taking chocolate every day as a vitamin. It also states (although not until the end) that one of the major funders of this research is Mars, Inc, the candy company. Who exactly is being paid to produce what science here? It makes me completely question the legitimacy of this study, if only for the monetay gains these scientists stand to make.

On a more scientific note, I'm curious as to how much we can change what we have receptors for in terms of memory and aging. If I can really have an impact on my brain's system for memory by what putting certain things into my system (flavanol, for example), what else do I actually have control over that science hasn't told me yet?

katherine's picture

face recognition

This week's discussion about the different functions that different neurons perform piqued my interest.  Although neurons have the same structure, they have the ability to impact a wide variety of behaviors.  This made me wonder if it is possible for us to strengthen certain neurons/behavioral processes more than others.  Can we train them to become stronger?  Take muscle memory for example.  Those who practice keyboarding become faster and are more efficient than people who are just learning.  Certainly if I had not practiced typing for so many years then I would not be able to type as quickly as I am able today. 
I thought that this idea was present in an article I read in the New York Times called Facial Recogniction: Faces, Faces Everywhere.  The article discussed peoples' ability to see faces in items ranging from clouds to grilled cheese sandwiches.  One idea is that our brain trains us to recognize faces over other objects so we are more likely to see them in non-human objects like potato chips.  Similar I to how we teach our muscles to perform certain actions, we teach our brain to do the same.  In other words, there is "particular area of the brain gives faces priority, like an airline offering first-class passengers expedited boarding."  This made me wonder why humans prioritize seeing faces and not hearing sounds for example.  It seems logical that we would see faces in non-human objects since faces are how we generally recognize people but this also made me wonder what kinds of things could go wrong if there was something wrong with the face recognition mechanism in humans. 

Caroline Wright's picture

Mirron Neurons

This rememnded me a lot of an article I read in Scientific America about Mirror Neurons.  As early as 10 years ago scientists thought that understanding and recognizing another person's action was attributed to a very rapid internal rationalizing process. This would mean that when I see my friend picks up a french fry and eats it, a part of my brain very quickly thinks about each of these movements and interprets them using past knowledge and experience to understand what I was seeing. However, recently this view has changed due to mirror neurons. These neurons have been found to fire when a person does a repeated, intentional action, something like reaching for something. These same neurons have been found to fire when a person is watching someone else do one of these familiar actions. So instead of having a bunch of internal reasoning processes every time that we see somehting happening in front of us, these neurons speed up to process. One of the most intesting things that this article talked about was that in testing a related idea on chimps, scientists found that during the experiment these mirror fired when the scientists themselves made any of these familiar movements. It is very curious to me to think about the possibilities and boundaries of the neural similarities between humans and primates.

AriannahM's picture


I understand how action potentials cause movement and reaction to outside stimulus. Furthermore, it makes perfect sense to me that having receptors depressed (i.e. touching something) can cause the sensation of touch, but how do thoughts cause action potentials? I’ve learned about action potentials several times now in my biology/psychology career and this point always gets me. I feel as though such a large portion of my every day happens in my head; thoughts, reading silently etc. Some of these thoughts generate actions ( i.e. thinking to sit down and write this post). But what I don't understand is how a thought is produced in the first place and then how this thought is able to generate an action potential. How do we think? How is a thought produced? How do our thoughts cause action potentials to occur and cause movement and sensations? There is still so much that isn't known about the brain that makes learning about it so fascinating.

LS's picture smell like a good mate!

I was reading an article in Scientific Mind on a nerve that may control which pheromones humans are receptive to and how this effects who we will mate with.  There was a really interesting piece on major histocompatibility complex (MHC) macromolecules.  These molecules are involved in the immune’s system recognition of foreign cells.  These molecule poke through the cells membrane and are inspected by the bodies T-cells.  If the immune system determines that the cell is foreign they will be destroyed.  Currents research suggests that an individual is less likely to be attracted to and thus mate with some one who had the same MHC as their mother.  In fact women prefer the odor of t-shirts worn by men who have different MHC than they do.  Men are also able to distinguish this from smell as well.  A protein fragment that MHC carries is what acts as a pheromone and this effects the bodies “bacterial flora” which the result from the breaking down of sweat due to these molecules.

Obviously it is important to be attracted to someone with a different MHC because the offspring of this union will have an increase immune system.   Also, it is important that one does not mate with their own relative!  As useful as this is, and as much sense as it makes it really surprises me!  When I meat someone for the first time smell is a standard of mine but I never though that it would mean anything more than what kind of soap they use or how often they shower!  I guess this just shows how alert our senses are and that they are sensing things they we don’t even know about, and this further effects our behavior.  I always though that whether I was attracted to someone depended entirely on my opinion of them and their personality I guess I have less control than I thought. …..Emily Dickenson wins this one..

Ian Morton's picture

Pheromones, the brain and sexual behavior

The role of pheromones and mating is definitely cool.  I've heard in the past that we sense that someone has a foreign immune system by how much they stink.  The worse they stink, the greater the difference in immune systems, the better the mate.  Anyone know if this holds any validity?  Just curious.  I suppose this might just something derived from the idea that sweat/body odor could potentially be better for attracting a mate than perfume. 

Anyway, I came across a study that I thought was pretty cool.  The study was covered in an article titled Pheromone Attracts Straight Women and Gay Men published in NewScientist.  Ivanka Savic lead a research team in Sweden and conducted experiments on pheromones.  In one experiment, Ivank Savic et al. found that smelling a male pheromone stimulated the same regions of the brain in women and gay men!  The pheromone used was a testosterone-derived chemical, AND, found in male sweat.  In both women and gay men, this pheromone triggered activation in the anterior hypothalamus and medial preoptic area.  There was no such activation in heterosexual men, but heterosexual men did show activation in these areas in response to EST (from women).  While there are no cause-and-effect conclusions to be drawn (whether AND triggered activation in men causes homosexuality or if AND triggered activation is the result of homosexuality), this research still shows an interesting correlation between brain function and sexual behavior.  Ivank Savic et al. believe that these areas are involved with processing hormonal and sensory inputs to form outputs of sexual behavior.  As there are no cause/effect conclusions, one is left to wonder how much the brain has control over behavior and how much behavior has control over the brain.

francescamarangell's picture

The 6th sense

Our nervous system moves all sorts of signals in fundamentally the same way through our bodies. This path involves sodium channels and action potentials, moving along axons in a process similar to the domino effect. Thinking more specifically about senses, our brains distinguish these signals by the location of the input and where it is received in our nervous system. If you scrape your knee, you know where the pain is coming from because the path of the signal moves from your knee to a region of the nervous system that registers pain on the knee. In terms of Emily Dickenson, all signals are a construction of the brain. Our brains interpret these senses and relay back to our bodies through experience. However, we can only experience that which our brains can interpret and our brains can only interpret signals for which our bodies hold receptors. So, as we said in class, our reality is limited to our range receptors.

When Professor Grobstein talked about animals and their varying range of senses (snakes can see infrared light, butterflies can see ultraviolet light, fish can feel electromagnetic waves) I couldn’t help but think about the December 2004 tsunami. After the tsunami hit, there was a lot of talk about animals and their “6th sense.” It appeared that animals were afraid and acted strangely before it hit, as if they new something was about to happen. It seems reasonable that receptors could explain this phenomenon. I read an article which suggested this theory. A large variety of animals possess specific receptors, whether it is regarding the earthquake or something unknown, which alerted them to the approaching danger.

Why don’t humans have this receptor? The article I read suggested that humans once had the same ability as animals to “sense” earthquakes and natural disasters before they occurred, but we have since evolved without that trait. Why is this receptor necessary for animal survival but not humans? Is the ability to sense earthquakes completely lost, or is it merely dormant in our brains? Do we have the potential to ‘relearn’ or ‘regain’ this receptor the way one can exercise the mind through meditation and grow new grey matter?

Darlene Forde's picture

society helps to determine which receptors (inboxes) we use?

Does society help to determine which receptors (inboxes) we use and whether we interpret them?

Francesa brought up a very interesting and fascinating concept. “Why don’t humans have receptors to “sense” such things as earthquakes and natural disasters? Is the ability to sense . . . merely dormant in our brain? Do we have the potential to “relearn” or “regain”?

Earlier this semester we discussed whether people/society can change genetic population. I argued that not only can we participate actively in such genetic control, but that we participate in this form of behaviour by allowing certain individuals to reproduce who would otherwise be unable to do so. For example, with the aid of science we can allow people who would not be able to reproduce normally (because of disease or genetic disorders, for example) the ability reproduce via artificial means. In this way, we have reconfigured our gene pool. Indeed, we could create a society in which only those who would be unable to reproduce unaided (“people with crappy genes) were allowed to reproduce, while those who would be able to reproduce naturally (“people with good genes”) were prevented from doing so.

In a similar way, I believe that we need to re-evaluate our ability to sense and interpret the world around us. Culture and society are an integral part of shaping the manner in which we use and interpret inboxes.

I believe that the “sixth sense” is merely a loose term applied to sensations that have been received by the body, interpreted by the brain, which do conform to traditional ideas of sight, taste, smell, touch, and hearing. It may merely rely on a different reliance on different sensation receptors. For example, we know that what we call taste is an experience that incorporates gustation, olfaction and tactile are the three components of taste, yet they involve at least three different types of receptors or “in-boxes”. What if the “sixth sense”—which allows individuals to predict behavior unexplained by our traditional five senses—is merely a combination of a wiring that we have learned to ignore? For example, when we wear perfume or cologne for extended periods of time we no longer smell it. Similarly when we are baking brownies, we notice the initial distinctive baked chocolately odour but overtime we no longer notice the smell. Yet when your roommate enters the apartment, she immediately gets excited because she knows it is “brownie night”. Have we become impervious to these inboxes either through prolonged use or because society refuses to recognize these interpretations as valid?

Many of us have had “gut feelings” that certain things were going to happen. One article in a Netherlands based journal Nederlands Tijdschrift voor Tandheelkunde, (loosely translated as) “A sixth sense: bone as mechanosensor” proposed that bones themselves are mechanoreceptors, sensitive to mechanical and physical change.[1] This suggests that the common phrase ‘I feel it in my bones’, may be accurate statement to describe a certain type of sixth sense. However, society generally does credit the bones as being a sensory organ. The mind/brain therefore may therefore break the association between feelings in the bones and the previous output. Therefore, the ability to make this connection, to experience this sense atrophies.

This example underscores the fact that we need to think more broadly and sophisticatedly about inboxes. For the most part we have considered external stimuli—primarily because these can be the easiest to measure and interpret. We have considered the puzzling case of outboxes or responses that do not appear to be the product of external stimuli. One article presented in the Journal of Internal Medicine entitled “The immune system as a sixth sense”, suggests that we need to be careful of our definitions of “inbox”. [2] In the article, researchers at the University of Alabama describe how the immune system and the nervous system “talk” to one another. These systems have “delineated hardwired and humoral pathways for such bidirectional communication”; in short we may now conceive of the immune system as a series of boxes with connections to the in and outboxes of the nervous system. In this way the nervous system may be “sense” threats to the body in the form of viruses and bacteria.

We have yet to develop an explanation for individuals who have the ability to anticipate natural disasters, or strange phenomenon, by the five sensory system model. It is clear that there are many internal and external mechanisms that may be at play. The ability to predict oncoming earthquakes may merely be a rare combination of a number of different types of sensory cells and neurons, both in and outside of the nervous system. But as with most important things there is still much work to be done on elucidating these mechanisms.

[1] Burger EH “A sixth sense: bone as mechanosensor” Ned Tijdschr Tandheelkd. 2002 Aug;109(8):312.

[2] JE BLOCK. The immune system as the sixth sense. J Intern Med. 2005 Feb;257(2):126-38. Review.

Molly Tamulevich's picture

That may explain...

As an anthropology major, i have come across a lot of texts illustrating the supposedly extraordinary senses of certain individuals and groups. Often, scientists are amazed by the sensitivity that people living in a less urban environment have to nature, to the subtle cues that most of us are oblivious to. I wonder if this is due to a more selective gene pool, an increased sensitivity to surroundings or a combination of both. I wonder about phenomenon that exist in animals that we seem to lack or not be tuned into. The sensitivity to earthquakes is one, but what about the feeling that many people have when they know that a relative has died? There have been numerous reports of people who either have a dream about saying goodbye to a loved one or a premonition that something bad has happened moments before learning that something has actually occurred to the person. Is that the same sort of sensitivity that animals exhibit when they aomehow know that their owner is going to return home? I want to know what is resbonsible for this isncreased sensitivity and what other things we might be able to perceive if we focused on them

emilie's picture

Neurodegenerative diseases

According to the National Institute of Neurological Disorders and Stroke, there are more then 600 neurologic disorders. Unlike cancer, which is characterized by uncontrolled cell growth, neurodegeneration is characterized by cell death. There is still little known as to what causes the degeneration of neurons. There is ongoing research in this field that is making new discoveries and providing new insights into the underlying causes of these diseases.

In certain neurodegenerative diseases, such as Huntington's, it has been found that an accumulation of clumps of toxic proteins. Dyneins are tiny molecular motors that are responsible for moving proteins around in nerve cells. They are also responsible for getting rid of the toxic proteins in cells. However, as we all know, the development of human body is an extremely complicated process in which many mistakes can be made. Mamy complications arise from mistakes in the genetic information. So if there is a genetic mutation that causes dyneins to be absent or defective, then clumps of the toxic protein causing neurodegenertation will appear and the cell function will then be compromised.


eden's picture

"Of all the things I've lost..."

I love evolution. I think it's great, and just outrageously interesting, so I think about it a lot and try to incorporate it into my mindset when I’m pondering things. Well. I was reading this book about music and the ear, and the author was describing the myriad of ways that hearing can be lost. One of the primary sources of hearing loss was age. As you get older, hair cells in your inner ear become less and less sensitive. You lose the ability to hear sounds in the upper register, and individual sounds, say, the difference between a B and a B­ flat, become less distinct.

Thinking about this in terms of survival, evolution, and sensing the environment, I come across something that weirds me out, or at least smacks my sense of significance upside the head.

When I first think of evolution and why we have such complex brains and sensory organs, it makes perfect sense. Complex brain = better able to sense and interpret environment = more likely to survive and reproduce. Okay, sounds great. Yay Evolution. But what’s crazy is that because physical evolution (not talking about culture, which of course does impact evolution in its own way) really just wants us to have lots of babies and then doesn’t give a rat’s what we do after that, we aren’t really “built to last.” AND THE FREAKY THING IS that means our brains too. We actually lose our ability to sense our environment, as in the case of hearing above, and many older people even begin to lose the ability to interpret their world. I once read this article about all these different physical characteristics that would be totally different if we were “built to last,” like having knees that bent backwards instead of forwards, and I thought it was so fascinating, but I never really thought to apply it to MY very own brain as well. I find it very odd and deeply disturbing that, evolutionarily speaking, our brains are just as expendable after we finish up reproducin’ as our ability to run away or climb trees. If our brains degrade just like everything else, where does that leave our “self-ness” when we are old? I mean, where does it go? I honestly will have to think about this some more, because seriously, that’s just kinda weird. Way to stab me in the back Evolution.

Kate Sheridan's picture

Evolution, why don't you love me more?

It's really bizarre for me to think of not only my body "betraying" me when I get older, but my mind as well. It makes me uncomfortable to think how fragile our existence really is. It doesn't take much to disrupt the system and become paralyzed or brain dead. If the spinal chord/nervous system is so delicate and essential to living, then don't you think it would have been evolutionarily beneficial to also "grant" it regenerative powers? Why is it that the most important aspect of our bodies is unable to heal itself? How did this system gain the evolutionary advantage? Is it a way of weeding out and sticking it to the reckless, brazen members of our species?

Also, although it's been said several times already in the forum, the idea that my thoughts, my emotions, my desires have a purely chemical basis from synapse to synapse is just wild. I don't think I'll ever get used to viewing my internal processes as something as clinical as that. I think that somewhere in the back of my mind, I'm still holding on to the possibility and belief that the most "human" parts of me come from something greater than my brain alone.

Pleiades's picture

I think you’re totally

I think you’re totally right about our bodies not being built to last. THAT’S WHY WE HAVE TO FIGHT TO SURVIVE. No joke. It’s my opinion that we certainly can strengthen our neurons, or at least the way they work together to affect our behavior and conscious (responding to Katherine). One of the most famous studies on cognition and memory loss was done by McArthur. He tracked a group of people from there middle ages to there 70-80. He found that part of the group still ranked in the top third of the population in there age group. These people kept both physically active and mentally active by doing crossword puzzles, reading and playing bridge (at least 3 times a week!!!!). They worked out there brains and it paid off. Another study showed that people that did a leisurely activity were 63 percent less likely to be diagnosed with dementia (June 19, 2003, New England Journal of Medicine). This is where the phrase ‘use it or loose it’ comes from. It is entirely true in the brain. As reported in the January 22, 2004 Nature, 23 healthy people, learned how to juggle. After three months, MRI scans showed enlargement of the gray matter in their brains—the part responsible for higher mental functions. Either existing cells had grown denser, more numerous connections, or the sheer number of brain cells had increased. When the study participants stopped juggling, their brains shrunk again. So while it is not possible to fight evolution, it IS possible to maximize what we gots.

Aditya's picture

Equipped for Survival

A very important notion that we talked about in class is that we are only able to perceive what we have receptors for. We are only able to percieve a very small piece of everything that is occuring in our environment. However I don't think this is a bad thing because we are equipped with the senses we need for survival, nothing more nothing less.

In class we summed up some of the senses some other animals have that we don't: birds: magnetic field, dogs: high pitches, sharks: heat, butterflies: ultraviolet light, rattlesnakes: infrared light receptors, fish: electric fields. 

So is it bad that we dont have receptors to percieve these other environmental characteristics? Absolutely not. If at the same time we were perceiving the senses we are already able to perceive including all these others we would have too much input all the time, our environment would be a jumbled up picture to us, and our bodies much more complicated. Our body has evolved to be the most parsimonious in order for survival. It is a balance being simplistic (using the same A.P. currency for transportation of information from all senses) as well as having just the right amount of senses optimal for survival.

For example, birds use magnetic fields to fly to warmer climates. We are equipped with the intelligence and manueverability to create technology to keep ourselves warm in warm weather. We don't need to sense magnetic fields.

It is important to be conscious of the senses we don't have and the reality we arent sensing. We are able to create technology that allows us to perceive the pieces of reality our bodies cannot, which leads to further understanding of the universe.

Meredith Sisson's picture

"Nothing more, nothing less."

About a week ago, I was sitting in the living room reading while my mother got her daily does of Oprah and I couldn't help but overhear some of the discussion that the panel of guests on the show were having. Reading this post, I was reminded of some of their words (which I will fully admit to being somewhat skeptical, if not cynical, about) and began to wonder what one of the men in particular would say about a reference to our "having just the right amount of senses optimal for survival."

After researching that particular episode of the show, I found one of his quotes that particularly struck me as something we as a class might have something to say about, especially after this week's discussion.

According to her guest, James Arthur Ray, "Science tells us that everything is energy, and so your thoughts are energy, your body, your cash, your car. Everything you think is solid, if you put it under a high-powered microscope, it's just a field of energy and a rate of vibration. And so are we." He went on to talk about the positive energies surrounding us and how finding a way to tap into them can help us manifest the lives we want for ourselves.

If we can get past the "self-help" portion of that, we get to his seeming dismissal of the idea that the five senses of human experience are enough for us to indeed "survive optimally". And I'm sure it would surprise him that the idea of spirituality has not been a larger part of this discussion.

Society as a whole does seem to be constantly searching to be more "in touch" and "in tune" with themselves, their lives, and the world around them and beyond them. And, perhaps even more surprising, is the success and fulfillment that many claim to find when these connections are made, when they find a way to perceive what has previously been beyond their senses.

If we are truly equipped with "nothing more, nothing less" than needed for survival, why do so many strive to perceive what is beyond their own senses? Even beyond the concept of spirituality, people constantly reference a "sixth sense" with pride, whether it be as simple (and common) as motherly instinct or as extraordinary and mistrusted as forms of parapsychology.

So there is a common knowledge (and appreciation) of this other form of imperceptible energy. But are all humans really capable of "tuning in"? Would it enhance our survival if we were? And if it would, why are the receptors of this energy so out of reach for so many?

Holly Stewart's picture

Limiting Factor in Our Sensible Reality

I’ve been thinking a lot about these action potentials, and they seem quite interesting to me. We seem to be able to describe how they work, and somewhat even why they work (i.e. because of a stimulus). But my question now is: knowing all of this, are action potentials the limiting factor/the limiting component in our experience of reality? Let me explain where this question is coming from, because it seems a bit out there, I know…

Last week we talked about how action potentials work, they are a moving battery that propagates down an axon using selective membrane permeability and concentration gradients. On Thursday we furthermore talked about what makes action potentials work. We have a resting potential, which is effected when it is exposed to ions such as sodium and calcium and if there are enough ions present, a threshold is reached and an action potential is produced. Okay fine. I’m really okay with things up to about this point. But did anyone ever consider how complicated this simple system is?

Evolution is a conserved process: if it works and the environment supports it, then don’t try and fix it. So evolution has created this system relying on concentration gradients, membrane permeability, calcium, sodium and potassium; and it seems pretty lucky that all these ions are hanging out in the right concentrations right around the neurons so that when there is a stimulus action potentials can be created. But what happens when it doesn’t work? I spent a good couple of hours scouring the web (specifically PubMed) for scientific research showing what happens when these factors (ions, membrane permeability, etc.) are there: things don’t work. Well that makes me a bit uncomfortable. Granted adaptation happens over time, but evolution has given full responsibility to these ions and principles alone, across all the different types of neurons (motor, sensory, interneurons). The system is dependent on everything functioning as it should.

We (humans) are such an intricately designed system, extremely refined and well-developed, but so much so that it seems highly unlikely if not impossible for us to adapt. What happens if calcium stopped being transported and localized near our neurons? What would happen if the sodium/potassium pumps stopped working? Well, it may seem easy to say that we would die, but I want to even take a further perspective and say that evolution has already made some decisions for us. Evolution has already decided which ions it likes and which principles to base the system of action potentials off of, and it is going to keep using that system as long as the environment supports it. But, what if the system we are using has dictated the reality that we are able to be sensitive to? I would argue that it has.

For me then, it doesn’t seem that odd that we are only able to be sensitive and experience such a small piece of reality. Evolution has made a choice in humans, just as it has in birds and dogs, and I’m not really interested in speculating if that choice was good or bad, simply realizing that it has been made. I’m sure what made evolution respond the way it did or what implications it has, but I do think it is interesting to think that action potentials may in fact be the limiting factor in our sensitive and experiential reality.

kjusewiczh's picture

Hearing Colors

In class on Thursday we talked about how we perceive touch and sound differently because of the different receptors we have and where they lead to in the brain. While we were talking about this I remembered hearing of a disorder where people's senses never fully separate. I looked it up, and it turns out this disorder is called synesthesia. In this disorder, the senses never fully separate. This causes many interesting outcomes. For instance, there are people who see colors when they hear different tones, or taste something when they are touching a certain object. I think this disorder leads to many interesting questions regarding the nervous system.

This disorder clearly implies that our senses were not always separated. This could explain how children learn so quickly when they are young. It would be much easier to learn if they heard the word red and then in their head saw the color red. This would ensure that words would connect with their meanings and could explain how children are able to learn so much so quickly.

The question that then arises is how the senses are able to be connected and then separate. Do nerve endings change location? I think it is clear that there are not taste receptors on the hand, since the taste does not always match up with the object. There must then be faulty wiring that occurs in the brain. I think the the question of how this occurs and why are very interesting and I would love to look into it further. After all, is it could to have our senses connected or does it impede our ability to move through the world in the same way everyone else does? Is any of that even important? Are our senses meant to be completely separated or are we meant to experience everything in a way that engages all of our senses?

lrifkin's picture

"In Red We See..."

I have been thinking about color perception all week! I read an article in the New York Times titled “How Do We See Red? Count The Ways” which discussed human perception of color. The article notes that different colors can hold unique meanings for different individuals. It also explained that each color can hold multiple meanings for one person. The piece, which was written just before Valentine’s Day, focused on the color red. Natalie Angier, the author, wrote
In red we see shades of life, death, fury, shame, courage, anguish, pride, and the occasional overuse of exfoliants designed to combat the signs of aging. Red is bright and bold and has a big lipsticked mouth, through which it happily speaks out of all sides at once. Yoo-hoo! Yodels red, come close, have a look. Stop right there, red amends, one false move and you’re dead.
Aside from my fascination with the human, and animal, ability to associate meaning with color, I was intrigued by the discrepancies involved with color perception. More clearly, the notion that although (assuming we are healthy) we are all born with the same cones and rods in our eyes, we can each still perceive red differently. While I might find a red door to be warm and welcoming, one of my peers may feel as though it is a sign to stay away. This led me to question whether we are all even seeing the same colors at all. When I see red, and my roommate sees red, is it possible that her version of red is my orange? As was considered in the “Hearing Colors” post which I am replying to, I have come to question whether our sensory perception is meant to be separate, or whether all of our senses are designed to work together in order to define our experience of various inputs.

leigh urbschat's picture

"Hearing Colors, Tasting Shapes"

The topic of synesthesia is actually what I'm writing my web paper on so I thought I would share some information since it's really very interesting. Like you said in your above post a synesthete has some cross wiring going on in their brain. According to a Scientific American article I read on the subject, when light reflected off a subejct hits the color receptors in the eye neural signals from the retina travel to the optical lobe at the back of the brain. The image is then processed to a further extent to determine characteristics like color, depth, etc. Afterward the information separating these characteristics is distributed into different parts of the brain, of which color information is sent to the area of the brain known as the the fusiform gyrus in the temporal lobe. The processing of numbers also occurs in steps, one of which occurs in the fusiform gyrus as well. Scientists now suspect that due to the close proximity of the processing area of both of these characteristics, wiring indeed must become crossed within a synethete's brain (it is very typical for a synesthete to see numbers as colored). They have also found that the hearing region of the brain also is within close proximity the the part of the brain that processes colors, which also may explain the occurence of seeing colors when hearing a sound.

To answer your question about whether this cross wiring enhances or impedes ones realtion with the world around then I would answer that it is just another way in which someone views the world. Just as we talked about in class how my view of a classmate is probably different from yours and different from that person's view of themself, a synesthete is going to view the world differently as well. Just in there case we are able to find an extreme enough difference that it is noteworthy to study. In the tests done in the article I read, the subjects know that the 5 they are seeing is not actually red to everyone else, but it is tinted red when they look at it (just an example). In other words, I don't believe that synethesia would impede ones view of the world, it would probably just make it more interesting!

alexandra mnuskin's picture

seeing without your eyes

I recently read a study that tested color-word associations. The study found that it took subjects a longer time to read the name of a color when it was printed in a contradictory color. For example it is easier for us to read the word “red” when it actually appears red. If the word “red” is written in green ink however, the time to read it is longer. This study further suggests that in our mind senses are not as clear-cut and separate as they may seem.
I know that in class we went through various senses that we as humans do not possess, because we lack the necessary channels that are sensitive to those stimuli. However it occurs to me to wonder why, if it is possible for the brain to create its own action potentials and stimulus, is it not possible to experience things for which you have no outer receptors. It sounds a little bogus I know…and actually reminds me of one of my favorite children’s stories by Roald Dahl called The Wonderful Story of Henry Sugar. In it, a man learns to literally see without his eyes. Logically this seems ridiculous…we know that we see with our eyes because we have receptors that are sensitive to light. But on the other hand perhaps this really is just an extreme example of our I-functions. During sleep for example, we are able to see and hear and even taste things without using any of our actual light, sound or chemoreceptors. In class someone mentioned how using certain meditation techniques you can train yourself not to perceive pain. Perhaps it really is possible to train your associations so that you have control over your perceptions.

csandrinic's picture

Seeing with your tongue

This discussion about just how connected our senses are to one another made me think of a very interesting article in the New York Times that I read recently, titled “Patient, Heal Thyself.” Over the decades, biomedical engineers have been working to provide technological cures for people afflicted with paralysis, deafness and other disabilities. The technologies that show the most signs of success are those that exploit the body’s regenerative powers of the nervous system and muscles. This research seems to show us that our brain cells have the capacity to rewire themselves radically (form new synaptic connections and dissolve old ones) in response to certain stimulation. For example, a neuroscientist at the University of Wisconsin designed a device that essentially leads the blind to ‘see’ with their tongues. By feeding data from a camera to a ribbon that lies on the tongue and is studded with electrodes, and tickling the tongue in a pattern that mirrors incoming data, subjects over time learned to interpret the data so well that they could recognize faces.

This article mentioned that with an extremely rigorous training regimen that included the electrical stimulation of his muscles while being aided to move on treadmills and stationary bicycles, Christopher Reeves was able to regain sensation to his limbs and could even feel them slightly. The notion that the brain can rework itself to repair its damages, such as injuries to the spine or to the nerves throughout our body is fascinating to me. I also think that it would be important to try to solve the complex nature of the way in which the brain interprets signals. How is it that when the normal pattern of connections that result in different modes of perception is ruptured, the brain is capable of rewiring its connections and creating new action potentials? 

Alex Hansen's picture

Brain Control

After reading this post, I remember actually taking part in that word-association game in a psychology class, and it was much more difficult to read a word that was colored differently than what was written.  There were a few other activities as well that make seem to have a lot of implication in brain and behavior correlations.  Another game was seeing a picture of an animal and then reading the word of a different animal right after it (very similar activity). 

Another included displaying a picture that can resemble different images depending on the way in which you look at it.  For example, the typical photograph that most people know of is an old lady or a profile of a younger person.  What is it about our neurons and the input that makes different people see different images?  What is it that makes us able to see the 'other' image when asked, can we control what our minds and our brain?  Do our brains at first work instinctually, but if in a way 'asked' to work a certain way, does it happen?  What controls what you want your brain to do happen?  Why is it that at times you can control it while at other times you are not able to?

 Another activity involved memory.  You were given a slide of names or words and you had to remember them.  Most of the time you remember the beginning and end words, but your brain seems to forget the words in the middle when asked to write down all the words you recall from the activity.  Why does this occur?  Why is it that there exist patterns of behavior for memory?  Number patterns that seem to frequently reoccur?  What is it about our brains and the neuronal activity that causes such to occur?  Does there exist a similarity across all humans?  Across all animals?

My last thought pertained to the previous post regarding sight and dreams.  I was lead to think about the images I see in my dreams and the emotions I feel.  Are those emotions true?  Are they a reflection of the emotions we experience while awake?  Are they a reflection of the emotions that we know exist on one level but seek to avoid?  As for the images, I was lead to think about what is real.  There are times that I dream up images that I've never seen before, and I wonder how my brain can create a picture if it has never 'existed' or is it that it has existed?  Does seeing an image in a dream make it a reality, make it so the image has existed?  What type of powers do our brains really have?  Do our neurons have to be in a certain state for different brain functions to come out?  What is the difference between being awake and seeing images versus seeing an image in a dream?

Jessica Wurtz's picture

Seeing Personality

So when I read this post, it made me think of something that is only somewhat related, and much more off the wall, but nevertheless, it came into my head. I started thinking about people who claim to be able to see people's "auras" that surround them and what color that person emits. I don't think I disbelieve that people can do this, it seems to me just another sensory cross-over like the people with synesthesia. When most people see and interact with others, they take in things such as like what people physically look like, what their voice sounds like, etc. Often, this also comes with an underlying impression of their personality, and sometimes is not based on anything factual, it is just what we often call instinct. So the average person might think that some people are cheerful, sad, mean, or any variety of personality descriptions. But it seems that a small population of people can actually see these descriptions in color form. The cheerful might be a sunny yellow, sad might be deep blue, and mean maybe black or something.

But the general population brushes these people who see auras off in disbelief. Why can't this just be another kind of synesthesia, and those people just happen to have a different way that their neurons are wired? We've been talking about how each individual perceives their environment differently than the next, so maybe this is just one of those different ways to perceive people that is rare among the general poplulation. My questions are the same as in the previous post about hearing colors, as to how different sense are connected, or disconnected, depending on how you want to look at it.

A.Kyan's picture

I-function for real?

I'm confused about the I-function.  Through meditation I have come to the conclusion that there is no "I" or a self, but only the mind and body working together (as I've posted earlier.)  But, I cannot deny that many twins (fraternal or identical) have a synergy in thoughts and feelings.  Especially when twins in different locales suffer the same injuries or sense the other twin is in danger.  How are two separate nervous systems and neuromatrixes somehow in sync?  This also goes for mothers' intuition and when people are able to sense a bad feeling that something has happened to a loved one, but can't explain it.  How do neuronal pathways make these connections?  Where do these inputs come from?  Scientists aren't likely to credit "psychic" abilities, but what is it in our brains that allow us to sense what is occurring in other people?  

This causes me to believe there is more to our brains than physiological pathways and connections.  What that may be, I'm not sure...  At the very least, I do not attribute it to a divine or spiritual power, but I do think it is within us to be extremely aware and access these abilities with the proper training.  Which leads me to believe that if there is such an I-function, than we can change or improve upon it.     

Student's picture

I think it's interesting

I think it's interesting just how little of reality we're sensitive to. We're only sensitive to that much for which we have receptors for.. we know that it's not very much, because of other organisms that have receptors we don't, and can acknowledge things we cannot. This made me wonder about the people we term mentally instable... could people with schizophrenia, or any of the other disorders, really just have more receptors- could they hear things that maybe are there, things that maybe we just don't have receptors to? Some people say they can see into the future. Some people are more perceptive that others, and think they can see, to one degree or another, into the mind's of others. Could this be due to different receptors?

We're looking to find out what's out there in space... what exists beyond that which we can see, which we can explore.. as we physically build the machinery to take us up and beyond.. it's interesting to think about how much we have here, that's undiscovered.. how much reality we can't even remotely begin to tap into, because we're not sure which direction we need to go in that.. we have so much here, in front of us, that we know so little about.. but yet we're looking for what we physically can see- what our senses can pick up. Maybe, when we look up into the sky, everything is there, clear, and communicating.. but we just can't see it, or pick any of it up. Maybe other organisms know exactly what's in space, just from looking, or feeling, or sensing.. maybe we're much, much less advanced, in comparison to other organisms, than we think are..

Sarah Powers's picture

A Slice of Reality

We are physically capable of sensing a lot of the world around us, not everything but quite a bit.  What I find interesting, is the small portion of what we're able to percieve that we actually pay attention to.  We are not always aware of the clothes on our backs, but if someone brings your attention to it, "Hey, your shirt's on backwards," you become extremely aware of it.If we took in, and processed to the point of awareness, every simulus that came our way, we would quickly go into overload. We wouldn't be able to handle it.  Add on to that the fact that neurons can express action potentials right in the middle of an axon.  Not only do we have to deal with the external, we also need to select from the inputs from within our own bodies.  So how does our brain pick and choose for us? What's the critera?Karen, you mentioned people with mental disorders.  Autisitics are a prime example.  Think of an autistic child who hates going to the grocery store.  He is so miserable because he can sense the light cycling in the flourescent lighting, almost like a buzz, and is acutely aware of all the people surrounding him, moving around, talking, making noise.  I think that his brain doesn't know which inputs to choose. He is experiencing more of reality than I would in that grocery store.  We think of autistics as disabled, but they might have a better idea of what the reality around us is.  

Stacy Blecher's picture

phantom limb pain

It was stated in class that we can only experience the world through the signals that we have receptors for.  We have a fairly limited amount of auditory receptors in our ears, photo receptors in our eyes, olfactory receptors in our noses and various pressure receptors covering our bodies.  We discussed the fact that activation potentials are generated in axons just under the skin when pressure is applied. 

At the time, all of that made sense to me.  If someone were to pinch the skin on my arm then the axon membrane in that area would change shape to allow sodium from the outside to flow in, thus starting the action potential that would propagate until it reached my brain and I said, ouch stop! 

However, after reading an article about phantom limbs, I’m perplexed.  How does one with no arm experience the sensation of that non-existent arm being pinched?  If the nerve endings have been severed in the amputation then where are the action potentials that signal pain in the brain coming from? 

The fact that people continue to feel pain in amputated limbs suggests to me that the brain is divided into specialized sections that are in some way hardwired to process specific inputs.  It also makes me think about the fact that we have so many sensory inputs and that the brain is only so large.  The specialized areas must be very close to one another.  This could offer another explanation for phantom limb pain.  Perhaps the area of the brain programmed to process sensation from the arm is right next to the area programmed to process sensations originating in the foot.  If this were the case then it may be possible that a few neuron bodies from the foot crossed over the boundary and implanted in the area meant to experience arm sensations.  The pain that the amputee experiences as arm pain is actually originating in the foot!

Just an idea, but it does help to explain two things: Where action potentials in amputees are generated and how the brain is organized to handle the vast amount of inputs that it receives.

Rebecca Pisciotta's picture

Neural Plasticity

Today in class we began discussing the functional mechanisms of individual neurons. We also touched upon the idea that our perception of the world is limited to signals for which we have receptors. We can perceive signals which come to us in the form of light waves, sound waves (via vibration), chemicals, and tactile stimulation. We are unable to perceive such things as electrical or magnetic fields, and many visual/auditory/chemical signals that are outside our range.

This fact has many interesting implications. The one that occured to me has to do with what it is that makes humans different from other animals. I fully subscribe to the idea that there might be nothing that makes us substantially different, but while thinking about sensory perception I had a few ideas. At first I was a little indignant, why do we think of ourselves as so superior? Birds have a more complete experience of the world than we do, we cant even sense magnetic fields. But, as Prof Grobstein pointed out, we created the compass. We also came up with radar, sonar, and infrared goggles. Through our technology we have been able to compensate for our inadequacies, and expand on our abilities. Maybe one day we will be able to genetically alter humans so that we develop neurons responsive to magnetic fields, biologically aquiring the senses we lack.

The idea that we can expand upon our sensory capacities is not unrealistic. This is due to our neural plasticity, the ability of our neurons to change, and neural networks to take on new functions. Many blind people, both those blind from birth and those who lost their sight at an early age, are able to use echolocation to navigate their environment. These individuals are able to perceive aspects of their environment by observing how an emitted sound is altered as it bounces off of objects. Through the use of PET scans and fMRI's it has been shown that the visual cortex is active during this activity. This shows that the area of the brain typically responsible for visual processing is involved in auditory processing in these individuals. The visual cortex is also active when a blind individual reads braille.

The ability of our brain to change through experience and learning means that we are not so constrained by our biology. Neural plasticity is responsible for everything we do. Without it, if our brains were static, we could not learn or remember. Possibly we would not have any concept of self, any ability to integrate ideas. Everything would be in one ear and out the other

Student Blogger's picture

Organization of Neurons

During my ballet class today, I was thinking about how my muscles are so used to the moves we do everyday in class. After taking ballet classes for 15 years, I feel that my muscles have not only developed to give me the most power for dancing, but they are also trained to perform in ways that will be most effective for helping me be a better dancer. My muscles have been turning out for so many years, that when I try to bend them normally when my feet are pointed forward, they try to compensate for the constant turnout and bend inward. My muscles have been trained to do certain ballet moves throughout the years that I have studied ballet; they have memory through repetition. Now, I believe this memory is a reallocation of my neurons not the change of their abilities or formation of new neurons. Nervous tissue does not regenerate as easily as other tissue in the body does, and therefore growing more neurons is not a viable explanation for my muscle memory. As we discussed in class, action potentials are the same throughout the nervous system. This means that there is no specific action potential responsible for the ability of my muscles to do an intricate ballet move without much thought. So, this makes me believe that the organization of these action potentials through repetition affects is responsible for my muscle memory.

Now, what about remembering song lyrics, poems, memorized verses etc.? During my English class last year, we were told to pick a Shakespearean sonnet to memorize and recite for the class. I spent at least a week memorizing a fourteen line poem that I would recite only once in my life, hopefully. My neurons reorganized themselves during that week while I was memorizing the sonnet, and when it came time to recite it in class, I had no problem. A few weeks later, without warning our teacher told us to repeat the sonnet. I stumbled through the first few lines, and could not remember the rest of them. The neurons in my brain, without constant repetition reorganized themselves and went back to their original state, before I had memorized the sonnet.

Aditya's picture

Neural Plasticity Ctd.

I do agree that neural plasticity is a  very important brain process necessary for learning, memory, maturation of functions etc. However, I don't think the brain's neural plasticity will be able to account for the formation of new senses. The way I perceive it, the example about blind people using echolocation to navigate their environment, is not the formation of a new sense but making use of current senses we have in a different manner than usual to compensate for their loss of sight. I don't think we will ever be able to acquire new senses unless there is genetic mutation in our DNA.  

RachelBrady's picture

New Pathway of Sense

In lecture we’ve learned that actions potentials are the “common currency” in the body; they are the same throughout the nervous system. These action potentials only produce different out comes depending on their pathway. We hear because there are motor receptors in the ear that propagate the action potential to a specific area in the brain. This is how all our senses are differentiated.

I was recently reading an article on proprioception; more specifically a disease that resulted in the loss of it. Proprioception, termed the “sixth sense”, is the unconscious perception of movement and spatial orientation arising from stimuli within the body itself. It is the sensory feedback mechanism for motor control and posture. “Proprioception provides information on the physics of the body, the momentary distribution and dynamics of forces acting on the limbs and their highly nonlinear interactions”.
           Loss of proprioception is rare and is caused by degeneration of sensory nerves from the neck down, but spares the motor neurons. Someone with this disease is not capable of feeling whether their body is moving and any bodily movements are elicited uncontrolled reflexes. However, “in the case of Ian Waterman… his strong will and memory of his body enabled him to learn to gradually control and guide his movements with his eyes”, but he was unable to move when he could not see his body.

         This concept raises many questions about the placidity of the sensory pathways we learned about earlier. From this specific case it would appear that the loss of certain pathways, through the degradation of those pathways receptors, results in the body forming new pathways as needed. And while this may not be a new sense, in that there are no new receptors. However earlier we differentiated our senses on their pathways (the receptors used, where they traveled in the central nervous system and where their eventual output was) in order that account for the fact that all action potentials are the same. While I’m not entirely sure that this is even plausible, it would appear from this line of reasoning that changing the pathway actually forms a new sense (sense in the way we currently are defining it).