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Neurobiology and Behavior, Week 6

Paul Grobstein's picture

Welcome to the on-line forum associated with the Biology 202 at Bryn Mawr College. Its a way to keep conversations going between course meetings, and to do so in a way that makes our conversations available to other who may in turn have interesting thoughts to contribute to them. Leave whatever thoughts in progress you think might be useful to others, see what other people are thinking, and add thoughts that that in turn generates in you.

As always, you're free to write about whatever thoughts you add this week. But if you need something to get you started, what further insights into both the nervous system and behavior come from understanding action potentials, receptor and generator potentials, and synaptic potentials? Does an understanding of the nervous system at the cellular level make it seem more or less possible that brain = behavior?

kenglander's picture

neurons as a computer network?

Are computers capable of spontaneously generating input? If we want to apply the neural network/computer network analogy, it seems that computers, like neurons, must not only be capable of processing input and sending it to  connecting computers/neurons, but they must also be able to generate their own input.
mmg's picture

Unfelt Cues (of the nervous system)

This week's discussion in class was the most fascinating one we've had so far. The idea that our Nervous system knows a lot of things we (our I function) are not aware of both intrigued and made a lot of sense to me.

A lot of us decide whether or not we like a person within the first few minutes of meeting them (or at least whether or not we want to continue a conversation with them). I am wondering if this is a combination of our nervous system's input (the other person's pupil is not dilated enough), or if it is our own decision that we dislike them (for whatever outward manifestations of their character). Or is it that even when we think it is our decision, it actually comes from our nervous system. This is interesting, for if we go Emily Dickinson's way, and the world is a construction of the mind, then isnt all of our minds hiding a parts of the world from us? (Sensory cues the nervous system picks up, beyond the five senses we are accustomed to).

I also read some interesting articles regarding menstrual cycle and pheromones. (That I can't find the link to now). It said that researchers who carried out a study in a nightclub/bar found that lesser men approached women who were menstruating. Evolutionarily this makes sense because women can't typically 'mate' when they are menstruating. Also, pheromones released by women when they were ovulating made them seem more attractive to the opposite sex. I was wondering what the exact evolutionary explanation for co-ordinated menstrual cycles are. I also find the idea of the alpha woman put forth earlier in this forum extremely interesting, and I wonder if the alpha women in our cultures are the one that are socially more popular.   

nafisam's picture

It is interesting to think

It is interesting to think that the nervous system can’t know something unless it has a receptor for it. In this case the brain does equal behavior. We can’t react to external factors that we can’t sense. This makes me wonder about fear, and what fear actually is. Would it be correct to say that we have receptors for fear, or is that a completely different part of the nervous system? When we are scared of something we definitely have bodily reactions to it, such as nausea, chills, sweats, pupil dilation, adrenaline rush, and a lot of other things that are not necessarily controlled by our I-function. In a lot of situations, we feel scared or uneasy even before we see or smell anything. How does our nervous system know to be scared of something? Why does the nervous system react to fear without the I-function? Can the mechanism of fear be turned on or off, or cease to function at all?
Max86's picture

Willpower - Action without Awareness

Our discussion concerning action potentials compels me to ask a potentially crude question.

Are action potentials reaching threshold directly responsible for not only compulsions, but difficult, reasoned decisions?

Take the following mundane occurence:

I am lying under the covers on an extremely cold night when suddenly I realize I left the front door unlocked. Now I am snug in bed, in a considerably comfortable position. What must ensue is a struggle between the urge to remain warm and comfortable and the "thought" or rational realization that leaving the door unlocked might very well facilitate an invasion of my home. Eventually, I do throw myself out of bed, but the process is perhaps analogous to a pressure system, wherein my urge to stay warm is gradually overcome by my fear of danger (or desire to remain safe).

Is this example entirely predicated upon action potentials? was my getting out of bed the result of a self-generated inter-neuron action potential reaching threshold? Or is a thought itself a successful (past threshold) action potential?

Also note that I claim a compulsion (an urge) is coming into conflict with a rational thought, but I wonder if there is any sort of dichotomy when it comes to imperative thought or action. That is, the "decision" to lock my door can only manifest itself toward action as an urge with an emotional basis. A rational thought cannot compel me to jump out of bed and sacrifice my comfort; what started off as an indifferent logical realization came to influence my actions as fear/desire. 

What I am trying to get at, is the nature of willpower. The above conflict between staying in bed and getting up seems illustrative of something significant. Action is an outpout; it requires motor-neurons to fire successfully. However, in the moment where a decision becomes an action, what we have is a thought bearing upon us as compulsion. What signals then, what action potentials, are operating when I finally will myself out of bed? I can imagine there is an integral dynamic to grasp in this moment, wherein thought becomes compulsion and overpowers a competing compulsion.

One thing i see hear here is that the I-function cannot manifest in a moment of action. If every action comes to bear as compulsion, then self-awareness loses salience in that moment. It was after all an emotional fear/desire that propelled me out of bed, not a logical series of thoughts.

Does this not seem an imperative matter to understand? Any claim to morality or responsibility needs to address the inescapable absence of awareness in the discreet moments wherein a thought becomes compulsion becomes action. 

drichard's picture


The discussions this week, though they may have been focused on the individuality and specificity of different nervous systems, served to remind me of the connectedness characteristic of humanity. We are all unique; we are all different. But our commonalities bring us together. When I am attracted to someone and my pupils expand, I am experiencing this connectedness. We are intimately in-tune with one another. Our symphonies are intimately in-tune with each other. The more we focus on the harmonius parts of the human song, the better off we will be.
aybala50's picture

not so different

The thing that I started to think a lot about this week is the fact that we are all so different. None of us on this planet are made the same way. Then why is it that we are able to be treated by the same medications, same methods of healing? Why is it that there are manuals for how a person works such as the DSM or any science book for that matter? How is it that doctor's are so confident in their prescription of medication? I guess we can't be so different after all. 
kenglander's picture

shared identity

While I agree that we are all unique individuals, I do not think this constitutes the argument that “none of us on this planet are made the same way.” I think a more appropriate statement might be that most healthy individuals have the same fundamental organs, but that our genetics, our environments, and our experiences shape us to react in different ways. This generalization attempts to acknowledge the commonalities between humans, but also recognizes that no two people are identical in how they react to a situation.

In a similar vein, I think it’s important to be aware of how small genetic differences can have huge impacts on anatomy, physiology, and more abstractly, behavior. Humans are currently thought to share approximately 94% of the same genes as chimpanzees. Clearly that 6% difference makes a huge impact. Seeing as humans are more similar to one another than to chimpanzees, we must share an even larger amount of the same DNA within our species. When thinking about medication, doctors should therefore be able to predict the relative effectiveness of treatments and medications. Of course, differences are seen with some people. For example, some medications warn that after taking the pills the person may experience headache, nausea, upset stomach, etc. Obviously these side effects do not occur in all people nor do they occur at the same level of severity.

DSM classifications also leave some room for classification. In schizophrenia, for example, patients exhibit a variety of symptoms—some have delusions while others experience hallucinations. However, their similarity in other behaviors leads to the diagnosis of schizophrenia. Thus while we like to think of ourselves as individuals who are unlike any other person, we must also remember that our genetic similarities are what keep ultimately unite us.
Sarah Tabi's picture

Receptors that don't go to the "I" function

I would like to go more in depth into the receptors that are not connected to our "I" function. How does that influence our behavior?  We don't know about each one so what if some individuals have more receptors than another individual? Couldn't that account for subtle differences in behavior? Especially since not all of the receptors can be identified.
bpyenson's picture

Receptors for Anything?...and their implications

As we were discussing potentials this week, in particular action potentials, I was particularly interested in the many different receptors that our nervous system maintains to detect stimuli (e.g. light, temperature, gravity, etc.) and convert them into an electrochemical potential.  Further, I thought it was interesting that our nervous system may 'know' more stimuli than we are consciously aware of. 


Albeit awesome, in the most literal sense, the nervous system has limits, or so I gleaned from the discussion: our model of sensory reception seems to say that we can detect all stimuli for which we have receptors (proteins) that are made that detect those stimuli.  This circular construction reminds me of the adage of medical microbiology who insist that antibiotics kill only the bacteria that they can kill, and not new strains that evolve resistance to the antibiotics.  In this vein, I am curious about a few things of sensory reception:

1.  Could we, humans, in theory, have all of the receptor for 'all' stimuli.  Since we perceive and 'create' our world in our 'mind's eye', is this not a reasonable proposition?  If so, could the fact that some people are more sensitive , in a broad sense, not just an emotional one, than others be a product not of their bodies maintaining a wider array of receptors, but that the same receptors they have and others have just may be activated by different thresholds of stimulus?  For whatever reason, could it be that the individual differences in perception are only a product of our different thresholds of sensation?  I vaguely remember reading about the psychology of pain, and how a current model posits this idea of thresholds to explain why different people perceive pain differently.

2.  I'm a sap for evolution, so here goes my evolutionary tangent to all of this.  Assuming that the threshold model is void, or largely 'more wrong' than other models, and that differences in perception between individuals, and species, are due more to differences in the acquisition of different receptors, then I am curious as to how more standard models of phylogeny (i.e. 16S, or 18S) compare to those that measure the occurence of certain receptors (i.e. cannabinoid, opioid) in some species rather than others.  Does it put birds closer to us than other mammals, for instance?

3. Also, could the different 'doors of perception' to quote William Blake be a source of madness (e.g. schizophrenia)?  Could it be that those who many would perceive as 'abnormal' or outliers because they 'feel' and 'sense' things that others do not are in fact just suffering from having different receptors than others?  Could it be that some schizophrenic patients do in fact sense things that others do not?  There's no conclusive way to tell, at least not one that i can think of.  If this were deemed 'true' in some sense, wouldn't this align more closely with the Ancient Greeks' notion of madness as something divine and well-respected because they believed that one who was 'touched' (e.g. Oracle at Delphi) could give insight to the rest of us that we couldn't figure out for ourselves.

OR, could it be that those 'mad' individuals are just more evolutionarily 'advanced' than the rest of us.  In a certain sense, could they be smarter because they sense things most do not.  Certainly that's a thought i think some believe after hearing of accounts  of madness like John Nash's.

4.  Also, why stop at sensory receptors that we know about.  Could there be receptors for a certain kind of logic, intuition, or intellect?  Just  a thought.

Lisa B.'s picture

Week 6

It is fascinating to know that billions of neurons may control behavior, and that the nervous system is so large that it is subdivided into regions based on location and function. For example the autonomic nervous system, made up of spinal and cranial nerves, sends and receives information related actions of the internal organs associated with sympathetic or parasympathetic stimulation. It is difficult to comprehend that without this antagonistic relationship between sympathetic and parasympathetic responses my pupils would not allow light to enter the eye or my blood flow to skeletal muscles would be restricted. Although many behaviors in the body are unconscious it is comforting that some behaviors, such as breathing, are partially controlled by the conscious mind.
fquadri's picture

taste receptors, propiosensors, and intuition oh my!

I'm starting to think that for the most part, brain = behavior. Activity in the smallest boxes (the neurons) affect the bigger boxes and overall affect our behavior. Receptors in our bodies allow us to process information from the environment and then allow the brain to respond accordingly (or ignore the inputs overall from time to time). However it's interesting to see how our reality is limited. Sure we can see, touch, smell, taste, and hear but we lack receptors to sense gravity and magnetic fields. People mentioned stories of animals who have a sense of knowing when people are about to die; I've heard that animals in the wild are more in tune with nature than we are so they can predict when the weather is going to turn into chaos. It makes me wonder what else we are missing out on; what else is going on in the world that we are not completely aware of? Is it possible to find a satisfactory answer?


The idea of multiple receptors from intuition to propiosensors is pretty fascinating. Propiosensors make sense but where is the box for intuition? Where are the intuition receptors? Do neurons process information from intuition receptors in the same way as they do from other receptors?

kdillard's picture

Cultural interpretation and physiological changes

It seems that what the brain picks up and focuses on in our environment, like the sound of a book falling on the floor or in making sense of all the noise at an amusement park, is determined by culturally induced meanings.  If someone from the first century was teleported into our world it seems that they would be bewildered and would most likely not be able to process the world in the same way that we do.  They wouldn’t see many things that we see and they wouldn’t recognize many of the things that they. This wouldn’t be due to problems with their brain, their cells, their neurons or their biochemistry.  They would be functioning like those of any homo sapien.  Their difficulty at interpreting their new reality would come from having a different  world view, values, cultural expectations, and interpretations.  They would not have developed the the cultural framework that allows for the selection and interpretation of meaning.  Do these cultural interpretations and values direct and influence these biochemical and neurological processes?  Would someone who experienced something differently due to significant cultural variation have the same physical and biochemical reactions?

Also, is it possible to have neuronal firings and physiological changes without cultural interpretation and the addition of meaning? 
ddl's picture

Overriding Sensory Input

     After our discussion this past week about how receptors are our bodies’ means of detecting and generating responses from the outside world, what became most intriguing for me was how the body can override the sensory input that it receives and generate thought about something else even though they are not physically experiencing it at that given moment.  A good example that could better exemplify my point, is how one could be looking at the floor (receiving the visual sensory input that says he or she is looking at a floor), and then allow themselves vividly imagine a beach or something else which is not present in the discernable environment.  In this case, one can seemingly override the sensory input that they are receiving, blocking out the information from their receptors.  What is the mechanism for this and does this ability dispel the view that thought and every other function of the brain is dictated by biological signaling from inputs that we are receiving from our surroundings?
redmink's picture


It was interesting talking about our senses that we don’t recognize in daily life.  Just like a submerged part of an iceberg, subconsciousness plays a large role in sensing and determining the human behavior. In my daily experience, I found it interesting that when I don’t wear glasses or contact lenses, I am so easygoing and when my vision is clear, I tend to get nervous more.  So, depending on the vision, my behavior changes.  I guess my clear vision suppresses my subconscious activity of the brain and raising the level of consciousenss and reason. I want to know if there is scientific evidence or observation about the relationship between human eye’s vision, brain, and behavior.

Reading previous posts above, I liked the discussion in which our brain uses selective attention to focus on certain stimuli. I wonder what leads our subconsciousness to pick certain stimuli.  Is it previous experience or genetics or random?  What would be the mechanism of picking out some of the many stimuli?

My second question is why would the brain constantly process input?  Why would the human brain want to satiate itself with stimuli?  Is it about maintaining certain chemical homeostasis—a scientific phenomenon of human’s instict of knowledge generation?

BMCsoccer01's picture

Coordinating Menstrual Cycles: Does Alpha Female Rule All?

We were discussing in class the different receptors that may be sensitive to and effected by external factors in our environment. Among these were the possibility of women's menstrual cycles aligning with each other due to receptors that women may have. In this argument, if there are gender specific receptors such as these, then the case could be made that brain = behavior. However, how are we viewing brain = behavior because biological behavior and social behavior are different.

The fact that there are hidden receptors that do not pass through our I-function would provide a reasonable explanantion for how one woman has a different menstrual experience from another and why one woman is biologically labeled as the alpha-female and makes other females regulate onto her menstrual cycle. Are there any commonalities in alpha females socially and biologically in terms of their menstrual cycles and the receptors that their bodies encapsulate? Do the women that exude alpha-female behavior in the social world also have the propensity of regulating their fellow women onto their cycle?

ilja's picture


In class we talked about our conscious actions (the actions that go through the I-function) and our unconscious actions (actions that our NS is aware of but we are not). The examples were unexpected, we discovered another piece of ‘common knowledge’ that we take for granted every day (for example that we have 5 senses) without really thinking about what lies behind these assumptions. These realizations make me wonder about our explanations of ‘unconscious’ actions or senses beyond the five conscious ones we experience. Some people belief in paranormal phenomena while others say it’s all random or by chance. I’m interested in the I-function, in the knowledge that our NS is aware of but we are not, and how much of it is just random or by chance.

Anna Dela Cruz's picture

Let's Not Forget About Glial Cells

In our continuing discussions on action potentials, synapses, neurons, and the senses I wonder why glial cells seemed to have been overlooked. I realize that there isn't much literature out there concerning these cells especially since neurons have been getting most of the attention. Whenever someone mentions "brain cells", he or she is most likely refering to neurons, the cells responsible for the hard wiring of the brain by sending and receiving both chemical (neurotransmitters) and electrical information. But I read in my research for the first web paper that neurons only account for approximately 10 percent of the brain. The other 90 percent is made up of glial cells. Is this alarming (ok, surprising to me) proportion indicative of some underlying concept of the glia-neuron relationship?

In my research about neuroplasticity, it was revealed that some glial cells perform some of the same functions that neurons were thought to be solely responsible for: emitting and receiving neurotransmitters. To further research on glial cells I stumbled upon an article (link provided below) describing a study by Rockefeller University on C. elegans that suggests the glial cell's importance to sensory reception. The study concerned the amphid, an organ in the C. elegan's nervous system that contains both glia and neurons. The organ contains 12 neurons 4 of which are completely surrounded by glial cells while 8 are partially surrounded with sensory endings exposed. To test the importance of glia to the neurons, the scientists removed the glia and observed the resulting shape of the neurons, the neuron's ability to respond to odors and temperatures, and the neuron's ability to absorb certain dyes. In the absence of glia, the neurons that were once completely surrounded shrivelled but the neurons that were once partially surrounded maintained their shape. However, these 8 neurons responsible for receiving stimuli from the environment were rendered useless. The C. elegans displayed trouble in finding their ideal temperature by crawling towards higher and higher teperatures. Their sense of smell was also affected by showing no preference or aversion to particular odors. From a molecular standpoint, the researchers focused on FIG-1, a protein secreted by only glia surrounding the amphid sensory organ. Without this protein, the neurons of the sensory organ had trouble processing external stimuli. Since FIG-1 in C. elegans resembles thrombospondin, the protein secreted by glia in vertabrates, the researchers suggest that the glia-neuron relationships observed in C. elegans may elucidate glia-neuron relationships in humans.

Without Glial Cells, Animals Lose Their Senses   

hamsterjacky's picture

behavior or chemical reactions?

I remember when i took an introductory psychology course in high school, my teacher taught me that behavior was just a bunch of chemical reactions colliding. It seemed as if the brain was recognizing many strange chemical reactions occuring inside of my body, and it ordered its own chemical reactions to calm or eradicate the unknown reactions and regain homeostasis.

Can someone consider behavior a form of reaction to maintain homeostasis? I mean, for example, when we're sad, we cry and it is said that a good bout of tears can help you feel better. So is that what we have emotions for? to maintain our body's balance but in an external rather than internal move?

OrganizedKhaos's picture

Beyond the 5th Sense

The way our bodies can take information from the outside world and produce signals in the nervous system helps to understand more about the way our bodies work in conjunction with the I-function. The way action potentials, receptor potentials, etc. all require this idea of membrane permeability is so intriguing. Although what the membrane is permeable to may change depending on situation, the way the basic idea occurs in all the different areas is nice.

The post 5th sense channels we posses that do not channel through the I-function are the most interesting to me. The idea that many things occur that we are not aware of wasn't exactly new to me (e.g. Halo Effect) but now that I am starting to understand why this happens, makes the idea even more interesting and believable, they are slowly being moved out of the unexplainable category and into the accepted.

jlustick's picture

Thursday's discussion on

Thursday's discussion on extra-sensory perceptions, specifically pheromones, led me to think about what other examples occur in daily life. One question I have is whether danger is at least partially an extra-sensory perception. Let's take an infant or very young child for example who typically responds to fear by crying. Some infants may cry when any stranger enters the room, but others only cry when the person appears particularly "scary," the sort that might even instill trepidation in an adult. Is this fear socialized? Has the child, at such a young age, been trained to recognized certain aspects of one's appearance/body language as dangerous? Or is there something else allowing the infant to sense danger? Do dangerous individuals emit some sort of pheromone? In general, I guess I'm wondering whether individual's determination of a situation as dangerous is due more to extra-sensory perceptions or socialization. Is the "gut" feeling that people get due to such perceptions?

I also wonder if people, like animals, can smell fear. Dogs, for example, are often said to be able to sense fear in humans, and this supposedly explains why they will bark/lurch at people who are scared of them. I wonder if this capacity to detect fear helps a predator find prey and then attack that prey. 

Finally, what are other extra-sensory perceptions and how are they connected to our unconscious? 


Leah Bonnell's picture


Thursday's discussion made me think of an article I recently read in the New York Times on the phenomena of "blindsight." Researchers have found that it is possible for someone we would consider blind, someone whose visual lobes were entirely destroyed, to navigate a cluttered hallway and recognize some facial expressions. The article states that this phenomena of blindsight comes from a second unconscious visual system located in a different part of the brain from the visual lobes.  

When I first read this article, I didn't really believe it, but Thursday's discussion on sensory receptors has not only helped me understand the article, but convinced me blindsight exists. Before class, I thought the only types of sensory receptors that existed were the basic five senses and as a result I couldn't really understand the article. In class we talked about how there are many sensory receptors beyond the five senses and that some of them are unconscious. Now I understand blindsight as one of these unconscious senses we discussed in class.,%20Benedict






bbaum's picture

1. The idea that neurons in

1. The idea that neurons in the brain receive many moreinhibitory signals than excitatory signals is very interesting if you think ofthe energetics of the process. The human body is designed to be efficient. Ourcells each have specialized functions, each protein has a specific job, and ourbody is designed to run smoothly and without much waste. It seems that thehuman body is wasting a lot of resources by requiring so many inhibitorysignals in the nervous system. Is an excitatory signal stronger than aninhibitory signal?


2. Could inputs produce inhibitory signals? I think thatthis process is possible because of my experience with distraction. I may bedaydreaming in class and suddenly be startled from my thoughts by a persondropping a book on the ground. In this scenario, my thoughts have been stoppedby an output from my environment. Does this mean that the sound of the bookdropping on the floor produced inhibitory signals that halted the actionpotentials produced by my thinking? Or does the book dropping produceexcitatory signals that are able to “overpower” the signals produced by mythoughts? I don’t think that an input has to be all inhibitory or allexcitatory. The noise of the book dropping may produce inhibitory signals thattravel to the box in my brain that is controlling my thoughts, while otherreceptors in my ears pick up excitatory signals that travel to another box inmy nervous system that makes me turn my head towards the sound. Without boththe excitatory and inhibitory signals, I would never be able to react to theoutside world because there would by no way to turn off the action potentialsthat started without an input. I think that most excitatory signals come frominside the nervous system. Our nervous system is constantly producing actionpotentials that are interrupted by action potentials that are produced frominputs. 

jwiltsee's picture

I'm interested in your

I'm interested in your second point, but from a little larger view.  You mention how do your signals react from an interruption of the book affecting your thoughts.  What I kind of want to learn more about is how does your body decide/organize what it will react to when you walk into an area full of many stimuli, for instance a carnival or a mall.  Does your mind sort through instantly the many excitatory signals that arise from the many inputs because of previous preconditioning???  It seems weird for the mind to be able to work that quickly to interpret so many inputs and allow you to focus on the one thing.
Bo-Rin Kim's picture

I know your brain uses

I know your brain uses selective attention to focus on certain stimuli. There have been studies that localized this selective attention ability to a certain part of the brain by looking at brain lesions in patients who lacked selective attention. I don't really know how your brain selects what to give attention to, but your current thoughts and interests probably drive your brain to focus on only what you want to or need to focus on. Thus, I don't think your brain sorts through all the information that it is given in a certain environment. I think a lot of the information may be unconsciously picked up, but the brain can quickly scan over and pick out what it will focus on and actually process.

This also suggests that there is a mechanism for inhibition in the brain since the brain is not processing all the information it receives. There are a lot of cognitive processes that require inhibition, such as being bilingual. People who speak two languages have to inhibit one language while using the other. I am debating between whether inhibition is a consciousness effort or if it happens unconciously. I guess it depends on what you are inhibiting. You could consciously inhibit certain behaviors, but you also unconsciously inhibit the external stimuli you are picking up but are not necessarily aware of. The question of what inhibition actually is in terms of brain chemical behavior remains. Does inhibition simply involve the ending of the propogation of excitatory signals or does it send separate inhibitory signal that releases chemicals that undo the work of excitatory signals, resulting in no output?

Sam Beebout's picture


How real is the idea of pathways in the brain? Thinking about boxes linked by cords to other boxes reaffirms that idea for me, but I am confused when we talk about action potentials because on the neuron level everything starts to seem so random. The idea that not all action potentials translate into behavior, that it takes a lot of action potentials firing at the synapses of a neuron to have that neuron send out its own action potential. The idea that inhibitory and excitatory signals happen at the same rate makes sense, but it leaves me wondering still about the extent to which the movement of these action potentials is determined. How much are our brains wired to fire in a certain way? The idea that the function of regions of the brain can change in their purpose and that what action potentials become is where they end up leads me to think that the boxes and lines between boxes are very fluid, but I also think that there are pathways physically there. How are these formed? How do they work?
Crystal Leonard's picture

intuition of another's presence

The idea that we receive thousands of sensory inputs from the environment that we aren't aware of has helped me think about intuition. I have always been aware of the fact that people can sense the presence of another person near then without consciously seeing/hearing/smelling them. Under the constraints of the "5 senses" I could never understand how people could do this. I had tried to rationalize it, to no avail. For example, I thought maybe the 2nd person's movements caused pressure disturbances in the surrounding air and a pressure wave propagated to the 1st person and activated the mechanoreceptors in the 1st person's skin. But this never sat right because any pressure disturbances that the 2nd person created would be extremely small and the air molecules' movements wouldn't have enough force to be perceptible. Now that I know that we receive large amounts of sensory information that we aren't conscious of, the problem is more easily explained. The senses of sight and touch are still unlikely sources of the 1st person's knowledge. More likely, the 1st person unconsciously detects chemical signals through the chemoreceptos in their nose (ie. pheromones) which alerts them to the presence of another individual.
Bo-Rin Kim's picture

I think you propose a very

I think you propose a very interesting question about intuition and the external signals responsible for our detection of other people we are not consciously aware of. The explanation of this phenomenon using pheromones is also an interesting perspective that I have never considered before. This question brings to mind a similar phenomenon in which people can "feel" when other people are looking at them even if the other person is far away and there are other people in the room. This cannot be explained by pheromones as there are other people surrounding the person and there is such a large distance between the two individuals. What would be the external signal that we pick up in this case?
eglaser's picture


We've been talking a lot about how the subconscious (the part of the nervous system that is not a part of the I-function) influences behavior and I was wondering if we could continue exploring this side of the nervous system. Is this how hypnotism works? Simply tapping into the parts of the brain that we are not always fully conscious of? What about dreaming? Is this where abstract ideas come from? What is the full relationship between the conscious and unconscious parts of the mind?

Is the I-function the only part of the mind that makes up our conscious selves? What other parts of the brain help us take in input and think about it? What other parts of our conscious sselves shape our behavior?

Brie Stark's picture

It makes a lot more sense

It makes a lot more sense to me how inputs can feasibly have no out puts -- as soon as we learned about the workings of the synaptic potential, it made sense.  Understanding that there are just as many inhibitory areas as excitatory areas definitely let me see the world of input/outputs clearer.  There could be a trillion inputs with no output, because there is the inability to sometimes continue the action potentials. 

 Looking at it this way, it makes me think that a lot more of my behavior comes from innerworkings of my brain, rather than my environment.  The impact of creating sensations within the nervous system seems to weigh a lot more, now.

jrlewis's picture

My Pony Told Me…

Last year, my pony told me that she didn’t want to compete at horse shows anymore.  She was extremely burnt out, physically and mentally.  She was asking for a long break from the strenuous schedule of chasing year end points. 

There are a variety of reasons why I might choose to justify my decision to limit my mare’s competition schedule this year.  It could be a case of projecting my feelings about competition onto neutral substrate.  Or maybe anthropomorphizing my pony and her behavior. 

Our discussion in Thursday’s class allowed me to add another option to the list.  The idea that my intuition about my pony is informed by the sensory input I receive from her.  This information is processed by my unconscious and crafted into a story that the I-function receives.  This explains how I can know something without knowing how.  Her behavior creates the sensory input that I receive from her and the way she behaves is a reflection of her mental state.  So I can interpret something about her mental state.  Maybe my pony was communicating with me.

For a similar story about a different observation see:


SandraGandarez's picture


I think that going into this class I had many misconceptions on my body and whats going on inside of it. The fact that everything isn’t standard and consistent worries me. If we have unmyelinated and myelinated axons and they can vary in diameter, how exactly do we have people who are specialists on these things. If they vary from person to person, who’s to say that performing surgery on one person requires the same things as surgery on another person. We also have many receptors that are responsible for their own section. How is it determined what receptor belongs where? Do they look different? Act different? Something that can be distinguished by scientists? The variations bother me just because it makes me feel a lot less secure in our medical system. I feel like my body and actions are a mystery to me now that I see them in a scientic light. If it’s my body and I don’t understand it, how can some doctor who just met me?
BeccaB-C's picture

I think it is important to

I think it is important to note, if we are really looking at this in 'a scientific light,' that there is a lot of consistancy in our body, despite our inability to really know truth, as we discussed with the loopy model in our first class. Everyone has some myelinated and some unmyelinated axons--its really a function of where they are in the body, what function they serve, what type of action potential and neurotransmitters are traveling through and out of them, rather than arbitrary differences person to person. Loopy science is based on summaries of observations. Scientists are only able to say what they have about meylination of axons and the difference in speed of action potential because they have seen consistent patterns of their location/function/size/etc. in many bodies and because they have specialized in looking at the exceptions that lead to inconsistency.