Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!

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.

You're free to write about whatever came into your mind this week, but if you need something to get you started: we're moving from the I-function (and mind/self/etc) to neuronal signals; is it a reasonable transition?  what help can we expect (or not expect) from the latter for the former?  


ewippermann's picture

Science and Politics and Brains

I read this article that tries to explain what's going wrong with and for liberals in politics today through cognitive science studies and research. Ideology is definitely a large factor in the I-function, and tabula rasa vs. environment arguments can be made, but I think it makes more sense when explained through the neuronal signals we're talking about.

Interesting quotes:

"There is no moral system of the moderate or the middle. Because of a neural phenomenon called "mutual inhibition," two opposing moral systems can live in brain circuits that inhibit each other and are active in different contexts."

" In one experiment, the strength of blink reflexes to unexpected noises was measured and correlated with degrees of reactions to external threats. Conservatives reacted considerably more strongly than liberals. Another experiment was based on the fact that disgust reactions create glandular secretions that change skin conductance. Subjects were shown disgusting images (like some eating a handful of worms). Liberals reacted mildly, but conservative reactions went off the charts."

The article is super long, but really great:

The I-function is neuronal signals, I think. The transition is reasonable for sure, and even if you believe in a distinction between the brain/nervous system and the mind/I-function, it's an awesome thinking exercise.

JJLopez's picture

Schizophrenia and Prenatal disturbances

I came across an article today in ScienceDaily ( about a new discovery made from studying mice.  It appears as though schizophrenia is the display of disruptions that occur to the brain before a baby is born.  They have located the area of potential disturbances to occur in the prefrontal cortex.  If we can determine that this disturbance occurs during before birth, then is there a way to prevent this front happening?  Some scientists think that schizophrenia is also a result of a specific genetic issue.  However, nobody is 100% sure that neither of the two theories are absolute.  My concern is that if this mental disorder has to do with prenatal disturbances in the brain, does this affect the "I-function" in any way.  In other words, would the person grow up to have a completely different personality than they do if there was no prenatal disturbance?

smkaplan's picture

Depression's Upside?

"Depression's Upside" is the title of a New York Times article I just read, which explores the possibility that depression can have a positive effect on mental health.

Andy Thomson and Paul Andrews, the authors of the paper cited, argue that an area of the brain closely associated with depressed people (the left ventrolateral prefrontal cortex, or VLPFC) is also important for our ability to intensely focus our attention on a particular problem or situation. Thus, when depressed people are using their VLPFC, they are also training themselves for more difficult mental tasks.

Thomson, a psychiatrist, seems to value this training above the current medical climate, which seems to favor medicating depression. "As a society, we’ve come to see depression as something that must always be avoided or medicated away," he says in the article.

"We’ve been so eager to remove the stigma from depression that we’ve ended up stigmatizing sadness.”

The article highlights a lot of objections to this argument, including that Thomson and Andrews homogenize depression, which in fact has many different causes and effects; that depression can lead to suicide, which certainly does not help the brain; and that when it is particularly severe, depression can be completely crippling, making any possible benefits seem somewhat remote.

But Thomson responds with a story from his clinical practice about how he treated a depressed woman with medication, only to find that while she was no longer "depressed," per se, the situation in her life that contributed to her depression had not gone away. "The point is the woman was depressed for a reason; her pain was about something," the article states.

I found Thomson's and Andrew's argument compelling, on a personal level at the very least. I've never been severely depressed—I can only speak to my own mild, occasional depression (which, after all, maybe doesn't even count as "depression")—but I've found that lifestyle changes are extremely effective at changing my mood. Often, I'm depressed—or perhaps just "sad" is more accurate—because I've been sitting around and not doing anything. When I get up, get things done, feel accomplished, I feel better. Moreover, when I've had longer periods of (admittedly) non-severe depression, I've come out of them with new insights about my life.

To me, this makes more sense than the immediate move to pathologize all depression and treat it with medication. While, in the end, everything may just come down to chemicals in the brain, there's no denying that life circumstances affect those chemicals. Or, in the language of our class, some aspects of depression may be purely brain-related: outputs with no inputs; others, however, have an identifiable external source.

As Thomsons asks, why do we assume that all sadness is inherently bad? Using medication to maintain some kind of artificial level-ness in mental state seems unhealthy—people get sad, people cheer up. Sometimes, it takes a long time, and in rare cases, it takes more than just time to clear it up, but overall, the fluctuation seems like a natural part of human existence—something to think about, evaluate, and discuss, but not something to medicate out of existence.

I'd appreciate any attempts to more closely tie this issue to the specific terms and ideas we've been discussing.

molivares's picture


It actually took me a while to wrap my head around the idea that the electrochemical gradient along axons acts as a battery.  Although it is a simplified view made to help others understand more generally what is going on, I found it more confusing. I think it is perhaps because it is too simplified.  After taking biochem and taking a close look at how the Na+/K+ and its role in our biological system, I’m having a hard time just looking at the bigger picture. But I guess that’s just part of learning how to exercise our brains.

Schmeltz's picture

Not Ready to Transition

I am still stuck on this concept of the "I-function".  I have been trying to better define it for myself and have become satisfied with the following explanation of what the "I-function" entails.  The "I-function" is our sense of what we can do based on the capabilities of our nervous system.  The "I-fuction", I think, is unique to humans in that we may be able to respond physically to certain inputs (i.e. Christopher Reeves and the foot pinch response), but the response is not a part of what we have constructed to be "us" even though we can recognize and acknowledge that there is a visible response or reaction.  In the case of a dog or frog, I would argue that the dog or frog does not realize the unfelt physical response due to a lack of or less developed self awareness.  In class we mentioned that there is a system within the nervous system that allows for the nervous system to look at itself.  We asked, is this the "I-function"?  Maybe. I would argue that only certain species have a nervous system equipped with this internal system that allows for the nervous system to assess itself.  I would argue that this is the difference between a human and a frog (and perhaps a dog).  On the subject of dogs, I have been wondering that if one pulled, pinched,or flicked a paraplegic dogs tail, if it would respond like Christopher Reeves would.  Do you think the dog has the cognitive capability to realize that even though he/she doesn't feel a response that there is still a physical resposne?  I would surmise no and that is how I would differentiate between a human being and a dog. 

sophie b.'s picture

One thing that I thought was

One thing that I thought was interesting about the conversation we had over whether animals do, in fact have an "I- function", is the comparison we made between the self awareness of animals and human babies. It seems that according to the mirror test that Professor Grobstein described, many human children probably wouldn't be considered to have the I-function, as understanding one's reflection in a mirror (and recognizing a dot on one's forehead as something that is undesirable) is not exactly innate. It makes me wonder, however, if the I-function simply develops with age/experience/experimentation or if it is a quality that can be trained?

I'm also not sure if I'd like to believe that humans are the only species with some sense of self awareness. I found an interesting article that described a mirror test in elephants- though only one of the elephants tested reacted to an X drawn on its face, most of the elephants in the study did not react to their reflections as if they were meeting a stranger. The elephants did, however, swing their trunks, moving them in and out of the mirror's view, to experiment with their own reflection, and afterwards began to experiment with their bodies in front of the mirror (on of the elephants used her trunk to pull her ear closer to the mirror). I think that this is more indicative of self awareness than attempting to rub a dot off its forehead- we wouldn't know if an animal likes or doesn't mind having an X on its forehead- but seeing their understanding of reflections seems to show some level of self awareness. 

meroberts's picture

I-function to neuronal signals

I think the transition from the discussion of the I-function to the discussion of neuronal signals is reasonable because of the example of Christopher Reeve. The neuronal signals in Christopher Reeve's body allow his hand to jerk back in response to pain but he has no control or awareness of his ability to move his hand. Therefore, it is essential to understand the I-function before learning about the mechanisms underlying how information is processed by the I-function. Even though Christopher might not be aware that he can move his hand, the neuronal signal that will enable his hand to move still exists. And it's the same signal as the one that makes him think that he can't move his hand.

yml's picture

Always interesting

Because I’m like a blank sheet when it comes to neurobiology, almost anything I hear and learn is new and interesting. I am still trying to process the information about neuronal signals we’ve learned this week and make sense of it, so I don’t have particular reaction to this week’s topic. I did find the example of battery to represent axon very interesting and helpful. Some people have mentioned in the forum that battery example might be oversimplifying what the brain actually does. I agree with this, though I liked the example for this reason. I often feel overwhelmed learning about neuro systems of brains, because I don’t have appropriate images in my head. Many of the visuals illustrating the activities are illustrations and not real picture of the activity (because we can’t really see them). So example like battery helps me to create visual representations of the information, which then eases me into the topic. Another interesting thing about examples like this is that they made me realize that when this complex brain activity is broken down into the small parts, it resembles other organisms or objects that seem like they are too simple to even be compared with human brains. These were just thoughts that occurred to me while learning about more new information about brain this week.


Colette's picture

The transition from the

The transition from the i-function to neuronal signaling seems somewhat unreasonable in that the transition is from a complicated higher function to the basics of how neurons work.  it would seem more reasonable to transition from the basics to the more complex and demanding. it would be something like understanding how horses walk before trying to explain how they gallop.  the study of neurons would show that they all work in the same way. the next step would be to look at the connections made up into pathways to see if some kind of organization of the neurons explains how higher functions are attained.  all of this is highly physical. higher functions may be more than physical?

egleichman's picture

the i-function, the unconscious, and the self

Interesting that we can distinguish "detection and analysis" of input from the "experience of seeing," and that that which we consciously experience bears little resemblance to what our nervous system experiences.  It makes me question the "stuff" of the self -- how can we have any sense of self awareness if we are not aware of most of the ongoing functions of the nervous system?  And at the same time, how can we function in any other way but with ignorance to this thorny reality?  If we embrace the uncomfortable notion that we are mostly products of our unconsciously- functioning nervous system, what happens to our individuality, our sense of self, our ability to understand -- or begin or pretend to understand ourselves -- so that we might understand others? 

emily's picture

a LOT of questions regarding animation, reality, and connections

 This week we talked about action potentials. Action potentials are extremely precise, all-or-nothing signals which are responsible for our neuronal connectivity and on a macroscopic level, our thoughts, feelings, urges, unconscious processings, and ultimately us! It is such a wonder to me how action potentials become animation. Carrie and I were talking earlier today about this, and we stumbled upon some really interesting questions about consciousness. The main question I have is how do our senses combine with everything else with in our brains (feelings, thoughts, unconscious processings, etc.) to yield an experience, a reality. Touching my keyboard, seeing the screen, hearing the keys, thinking a thought, pausing my thoughts as I type them, continuing where I left off, relating to past memories (my conversation with Carrie), acting, thinking, subconsciously thriving...this is my reality right now; how do propagating changes in concentration across a semipermeable membrane generate this WORLD?

My dreams are often hazy, but on rare occasions I have extremely vivid dreams which feel like reality. This must be the brain creating its own outputs, its own action potentials, in lieu of any sensory stimulus. But, what is it exactly that gives a vivid dream its "vivid-ness", its vivid quality, as opposed to duller dreams. What is making our mind and body (I know everyone's had a dream where they felt like they were falling!!!) feel REAL?
...hope this makes sense

We were also talking about the nature of these connections. Carrie wrote her first web paper about vegetative states vs. comas, in which levels of consciousness vary. If the connections within the brain regarding consciousness are severed or many are broken, can these connections be rebuilt? If so, are certain levels of consciousness learned as opposed to being innate? How do connections re-establish themselves? How to these connections form to begin with (I picture a little axon creeping along in the brain like a root in soil)? Action potentials allow connections to interact, but do they help form connections? How could the help "form" a connection if there is nothing for them to "form" on? How do connections become learned?
...a summary of this string of questions: What's up with connections?????


cschoonover's picture

The Renewal of Consciousness

 Last week’s discussions about action potentials, signals, and connections got me thinking about consciousness again. In my web paper, I mentioned research that showed signs of consciousness in patients who were said to be in vegetative states. What I didn’t go into detail about, and what I am questioning now, is how this consciousness is lost and then regained. Consciousness, as we’ve talked about in class, comes from neuronal connections and signals from action potentials. So how is this consciousness lost? Do action potentials cease? If they do, is it a matter of an inability to reach the threshold (since action potentials are “all-or-nothing” events)? Or is it more complicated; for instance, are connections broken, and if so how? If this is the case, can these connections be rebuilt, thus restoring some semblance of consciousness? This seems like a much more difficult task since we are born with some connections and create more throughout our lives as we learn and receive new information. Rebuilding a certain, specific set of connections almost seems impossible. And how do the action potentials make these connections? I know I have a lot of questions and I guess what I am most curious about is the method by which some small amount of consciousness is returned to people who seem to have lost it all.

On a somewhat different note, my conversations with Emily have led me to wonder how these signals from action potentials are transformed into the thoughts, feelings, desires, etc. that we experience daily. These animations are so variable, within an individual and across a population, that there must be a thousand ways these neurons can be connected to generate such a diverse range.

kgould's picture

 I've learned about

 I've learned about electrical and chemical signaling in the brain before-- on more than one occasion, actually. I knew the textbook explanation that I've learned in a series of bio classes... but, as always, Professor Grobstein has changed the way that I understand the intricacies and complexities of life.

Thinking of the electro-chemical gradient along the axon, of the negative/positive charges, as a series of batteries moving across and along the axonal membrane actually made the concept easier for me to grasp. I do have to admit that it took more than a good minute to wrap my mind around it. The idea of the batteries across the membrane and ALONG it, thereby propagating the action potential, made more sense than the idea of chemical and voltage gated channels and pumps... doing things...



Congwen Wang's picture

Appreciating organisms; "I-function" boxes?

I personally don't like the analogy of the eletrochemical gradient as a battery because the model of battery is too simplified. I believe that most people still tend to think a battery as an isolated little box with potential/voltage. However, the potential across membrane is established and maintained in a much more complicated fashion. Think about it: we consume nearly 1/3 of our ATP just to maintain the difference of K+/Na+ concentrations across membrane, just to prepare for the moment of action potential. It's defenitely not as easy as putting a battery into some electronics.

The rest potential is a good example of homeostasis. I always think to understand homeostasis is essential for studying organisms. Homeostasis is dynamic - more dynamic than normal equilibriums - because there are so many macromolecules involved in this seemingly stable process.  Although all complicated biological processes can be broken down into simple chemical reactions, the existence of macromolecules still makes these reactions different from those occuring outside of organismal world. The simplification of these dynamic processes makes it easier for us to understand, but oversimplification is not ideal for further understanding biology. To truly appreciate the brilliant design of organisms, sometimes we have to embrace the complexity of biological processes.


Some other thoughts about "I-function":

The intriguing concept of "I-function box" remotely reminds me of the projection in brain. I heard that our consciousness and dreams are related to the regulation of projection during sleep-awake cycle. I tried to find some articles on this topic, and the limited information gives me the impression that there are several structures that generate different projections to different places. Does that mean our "I-function box" is not a single box, but many boxes wired together? And since many of these boxes also have functions other than projection, maybe there shouldn't be a discrete category of "I-function boxes"?

kdilliplan's picture

Why This Particular Connection?

I think it’s interesting that we’re jumping from discussing the I-function to discussing the nuts and bolts of neurons and the way they work because it seems like neuronal activity is not controlled by the I-function. For instance, if someone were to ask me to make a specific one of my nerves propagate an action potential, I wouldn’t be able to. If someone were to ask me to wiggle my toes, I’d simply wiggle my toes. I wouldn’t initiate an action potential in the section of my brain devoted to the I-function that would then tell the nerves in my foot to tell the muscles in my toes to contract and relax, producing the behavior known as toe-wiggling. As far as I know, people aren’t capable of directly influencing the most basic behaviors of their nervous systems just by wanting to. I am also of the opinion that the I-function is only a very small portion of the inner workings of the nervous system, and it would seem that all neurons, no matter what their role, behave the same way at the most basic level. So my question is this: are we simply moving from the I-function to neuronal signals because we need to move from a general discussion of nervous system behavior to a technical discussion of nervous system logistics, or is there a specific point to be made about neuronal signals and the I-function specifically? I personally am more interested in how neuronal signals, which (as far as we’ve discussed) all behave similarly, can produce such diverse responses as evidenced by the vast array of different behaviors among individuals of the same and of differing species. This is partially because I find such behavioral diversity fascinating and because I remain skeptical of the necessity of an I-function in explaining behavior. 

AndyMittelman's picture

             The transition

             The transition from I-function to neuronal signals is an interesting one. The condition experienced by Christopher Reeves is now more logical in my mind. I am continually amazed at the fragile detail our body relies upon to communicate signals. The gated channels that our body employs seem so purpose-specific, it is astounding how far evolution brought us.

            Could you migrate the I-function? If the I-function is a discrete box, and may be malleable (as in the case of Christopher Reeves), could you alter its boundaries through methods other than injury? How could we remove certain input? If the action potentials are conducted along the axons through the opening and closing of ion channels, I wonder if it would be possible to intentionally “shut down” the battery. Maybe we could neutralize the potential difference across the membrane, or prevent the temporary reversal that occurs during depolarization. What if we shut down the Na+/K+ pump? If the signal could not be conducted, it would be like removing a part of the input. This may be how anesthetics work…? I might look into this for my next web paper.

            Also, check out this video: It’s about the mirror test for self awareness that we were talking about on Tuesday. Pretty interesting! 

Congwen Wang's picture

The idea of shutting down

The idea of shutting down Na-K pump is quite interesting, though I don't think it would be possible in practice. The electrochemical gradients of Na+ and K+ are so prevalent in our bodies that it is not quite possible to only shut down the Na-K pumps in certain neurons.  I think typical anesthetics usually works on the synapses because it simulates the way nervous system regulates itself. And also because synapses bind with neurotransmitters, the inhibition/activation can be localized and controlled more easily.

lfrontino's picture


It is so abnormal for me to think of axons as a battery system. I usually think of batteries as something so industrial and metallic. I don't really associate my organic brain with something like this. However, this just makes me realize that once again my definitions are limited. Actually, a battery is just a series of electrical currents, and of course my brain could act on this. I think of the brain as something so complex and mysterious, but once it's broken down it is really made up, just as we said in class, of boxes within boxes, all connected by cables. How is this any different than a battery?

Saba Ashraf's picture


            This week during class, it was interesting to find out that all axons contained the same signal. Initially, I was somewhat surprised about this, but when thinking about the axons and signals, it made the most sense that there was only one type of signal. The pathways of the cables are what really differed, so the signals involved in moving one’s eyes and feet were identical. However, the pathways and cables containing the signal were completely different. Also, the concept of time and the nervous system was an interesting topic during class.   At first, the idea of the brief disturbance by the action potential taking milliseconds seemed quite fast to the class. However, when comparing it to the speed that an electrical signal travels at, which was the speed of light, the action potential seemed extremely slow. This brief disturbance that we were talking about happened to be a switch taking place between the positive and negative signs on the axon.  I had never known that an axon was so similar to a battery, until we discussed the diffusion and selectively permeable layer.  In fact, all it took was a selectively permeable membrane and a concentration gradient of the ions to create this battery. Hence, we were able to find out that because there was a lot more potassium inside the battery than outside, the inside of the axon happened to be negative. At first, this may have seemed confusing, but the example using the red and blue particles in a box with a semi-permeable layer and a force acting upon it helped clarify this confusion.   Therefore, when the battery in the axon went from inside negative to inside positive, a gradient was created in which there was more sodium outside the axon than inside.

aeraeber's picture

Macro vs. Micro

Going from the I-functiuon to neuronal signals is, in my opinion, quite a leap.  A large-scale view of the brain as it relates to the idea of self and what we can and cannot control is very far removed in many ways from the molecular workings of  the brain. Nevertheless, the two ideas are related enough to make the transition reasonable. The idea that what we as individuals are made up of is vast network of chemical signals and pathways and that those pathways connect the I-function to other parts of the brain, allowing us to be aware of and intereact with the world around us is a bit bizarre at first glance. But at the same time it makes sense it terms of the fact that thinking takes time, that we forget things momentarily and then suddenly remember them later, and that drugs affect the brain in general and the I-function in particular. Having a concept of the I-function, we are better able to look at neuronal signals in terms of the function of the brain as a whole, rather than just as an isolated idea.

In class, we talked about how neuronal signals are all the same, and it is different pathways they take that create different actions. It makes sense that all action potentials work the same way and operate under the same principles, but I'm wondering how neurotransmitters fit into this picture. If they don't change the signals, then what exactly do they do? And why are there so many different ones? I know that some of them induce an action potential in the next neuron, and others of them inhibit an action potential, but I have a feeling that it's more complicated than that, since everything about the brain seems to be complicated.

Lauren McD's picture

The difficult transition

The transition from the I function to neuronal signals seems like a huge leap for me. Obviously the two are connected, but the I function and other important characteristics of the human brain are removed in my mind from neuronal signals. Neuron firings are like the building blocks to the I function, except that there are many stages before the I function is reached. I think because of these countless steps, it is hard to see how the two interconnect. Despite this difficult transition from something as complicated as defining ourselves to understanding things on a molecular level, there is no other way to make the transition. Individual neuron firings lead to a traveling signal, which leads to an interpretation of that signal and eventually a response. But we have not dealt with complicated responses such as defining the self relating to the response of a stimuli in class. This is difficult because the gap between neuron firing and the I function is so great that it is hard to know where to begin to fill it. That being said, any transition between the two would be difficult. Perhaps it would have made more sense to start on a molecular level and eventually build up to understanding things such as the I function. However, it is also important to intrigue learners with the ideas that they will eventually be able to understand. This allows for a goal at the end of interpreting the complications of the brain on a molecular level. It is also hard to understand the connections between the two because they are so different from each other. We cannot see, feel, or slow down a neuron firing, and yet we constantly think about the identity of ourselves. Something as reachable as the I function is hard to connect with in depth molecular actions.

MEL's picture

Neuronal Signals


I think the transition from learning about the “I-function” to learning about neuronal signals is reasonable. Neuronal signals allow the “I-function” and other parts of the brain to transmit and receive signals. It is interesting to think of the Na+ / K+ pump as a battery. It is the action potential created between the opposite sides of the membrane that propagates the signal down the axon. It’s hard to imagine that all of the signals that are transmitted and received in our bodies are controlled by the transfer of charges across a membrane. I’m surprised we as humans can do things as quickly and consistently as we do when every action we take is controlled by the transfer of charges across a membrane. I also think it’s very interesting that all neural signals are the same, it is the neural pathways that are different. What what it is that makes our neuronal pathways different and how does that really change a response?  I am still pondering the questions that we brought up in class. How can signals start in the middle of the nervous system model box? How can signals stop in the middle of the box?


natmackow's picture

The I-function and self-awareness

This week we clarified the idea of the “I-function” a bit in our description of signals and connections. If all signals are the same, then it must be the pathways through which they travel that affect a person’s behavior. So, if those cables that connect the “I-function” to the rest of the brain/nervous system are blocked or disabled, signals generated in the I-function will not be able to reach the rest of the nervous system. In addition, signals from the rest of the nervous system will not be able to use pathways that lead to the I-function. Such is the issue in Christopher Reeve’s case in that “he” was unable to generate outputs because the signals he generated could not reach the rest of the nervous system to, say, move his leg.

This situation is interesting because it demonstrates that one’s mind is not usually separate from one’s brain and that this connection is essential for an individual’s survival. While there are certain behaviors that the I-function does not seem capable of influencing (heart-beat, organ function, blood flow, etc.) it does seem to function as a “box” that creates a representation of the nervous system. It almost allows the nervous system the ability to view itself, its actions, its inabilities. This function is crucial because an ability to look at one’s actions and to be self-aware allows an individual to better adapt to changes in the environment and in oneself. In addition, it further allows ones actions to be a bit less instinctual and more learned (based upon the situation and previous experiences). I am interested in learning more about the idea of self-awareness and its advantages.


mcchen's picture

Neuronal signals

 While the transition from I-function to neuronal signals seemed a bit strange at first, I am starting to see a connection.  It seems like we are zooming in on the signals which allow us to experience the I-function and other feelings.  If we are able to understand the propagation of neuronal signals that may give us some insight on how the signals travel and how as individuals interpret the signals differently or similarly.  I generally prefer thinking about the larger picture and how we think rather than the small neuronal signals which govern our functioning lives, so this is definitely a different approach at analyzing the mind.  For the neuronal signals to start, I can only assume that there needs to be some stimulus to provoke it.  Would it be an external signal? Or can internal signals prompt neuronal signals since neuronal signals are internal as well? I feel that the analysis of neuronal signals in relation to the I-function complicates matters due to the unanswered question of where/how do signals start.  Is there a certain "box" which is the source of all the signals and it is the only box that can generate an output without an input? But then there's the question on how that "box" can generate a signal all on its own without a stimulus.  

mcurrie's picture


 Learning about how signals work could definitely help with understanding the whole output without input where a signal could start in an axon without getting a signal from some connected neuron. This could be due to the "battery" movements and with their movements they create a potential that occurs in the axon and then creates an action. This signal would then not be influenced by an input either from another neuron or from an outside stimulus. I'm still wondering if the output signal is random or not since the movements of ions or molecules are random. I know there are the channels and pumps that aid in keeping a gradient so maybe the signals are random because they can be influenced by the pumps. Can't wait to figure an explanation using what we know about signals. 

I do understand signals and how they function with sodium and potassium ions but I am a little confused on our explanation of potentials with batteries. I understand what a battery does but when talking about action potentials I became confused. Could someone maybe explain action potentials more clearly without using batteries?

gloudon's picture

i-function to neuronal signals

 The 'i-function to neuronal signals' concept seems reasonable to me.  It makes perfect sense that the signals are all the same and the pathways are different.  If the signals consist of electrical/chemical potential energy, then it is understandable that they are all same.  If you supply power in the form of electricity to a lamp, the energy only has one pathway to take and stimulate something, which turns on the light.  In our much more complex bodies, the signals are supplied and take one of a multitude of pathways.  Right now, I'm not so sure how the body chooses which pathway the signal travels through.  

One example of me not understanding how the brain decides with pathway the signal is sent through (which isn't working for me) is when I try to move each toe individually.  I think, "i'm going to wiggle my pinky toe," and sometimes it wiggles, but usually it wiggles along with the rest of my toes?  I didn't tell them to wiggle.  To me, this seems like sometimes the i-fuction is messing up in aligning the signals with the correct pathways.  

Jeanette Bates's picture


             I think that the transition from the I-function to neural signals is just fine. One part that I found especially important was the fact that “all neural signals are the same, it is the neural pathways that are different.” I think that this fact can help explain why only certain things are affected by the I-function, or at least the I-function as I see it. In order for something to be a part of the I-function, it would have to be connected to specific pathways that send signals from the part of the brain that has the I-function to specific parts of the body. “We” are connected to the parts of the body that we control. Literally. But more importantly, I think that talking about multiple pathways and connections can also help me understand why sometimes things seem to be a part of the I-function and why they don’t at other times. Considering the millions of different neural pathways that exist in the human body, I think that it would be reasonable to think that there are many different pathways that can lead to the same part of the body and even create same response. Therefore, sometimes the I-function may give off a signal that would go down a certain pathway and create a response, such as breathing. But sometimes, there might be a part of the brain that is not within the consciousness that will send a signal that will go down certain pathways and end up giving the same response, which in this case, would also be breathing. The starting places and the pathways may be different, but if they end up in the same exact place, then they might be able to cause the same thing to happen. Their ability to switch roles, I am sure, is also determined by connections between those parts of the brain and the things that they can control. I think the fact that the pathways determine function, not the signals themselves, makes the I-function make a lot more sense.