week 2 - Neurobiology and Behavior

In the recent January 29th edition of Time Magazine, a mind and body special issue, one article in particular caught my attention. Daniel Gilbert and Randy Buckner's essay entitled "Time Travel in the Brain" springboards from the very concept of inputs and outputs and delves into what is in fact happening when neither input nor (ostensibly) output is present in the brain.

The piece begins with a rather striking assertion: "What are you doing when you aren't doing anything at all? If you said 'nothing,' then you have just passed a test in logic and flunked a test in neuroscience." Put simply, the human brain has what can best be described as a vast network. When we appear idle and removed from present tasks, our brains are actually active. Within such a network, one is able to retrieve memories of past occurrences as well as access thoughts regarding the potential future.

However obvious Gilbert and Buckner's general point appears to be, there nonetheless lies a truly profound and perhaps even supernatural undercurrent to this explanation. The power of one's imagination is indeed boundless, moving freely from past to present to future. In terms of the past, one may recall a fond memory. As for the future, one could envision an important upcoming event. We have the ability to escape the present for a period of time and experience another time all together.

Behavior and the brain are so deeply interconnected in ways that scientists can’t always explain. I read an article from last week about addiction in the New York Times titled, “Damage to part of the brain appears to end urge to smoke.” The article described how a man who suffered a stroke, and consequently damage to a portion of his brain, lost all desire to continue smoking. It had nothing to do with wanting to quit because of his health; he simply didn’t feel the urge. Scientists conducted a study regarding this case and several others just like it and they found that addictive behaviors show origins nestled in a specific region, the insula. It’s been linked not only to smoking but to all addictive behaviors. I find it interesting to think that the output functions for all addictive behaviors can be wrapped up in one designated location of the brain. As I read this article, I was thinking about our class discussion on input-output systems, and how does this situation fit into the input-output spaghetti-bowl or box inside box models. I wonder if all addictions are processed the same way within the brain, because they share a common origin and show similar signs of activity on MRI tests. If this were true then this could be an example where the same input of information leads to two separate outputs. The same addictive signals processed in the brain could potentially result in one person smoking a cigarette and another biting their nails. This variation on outputs fits into our discussion on the individual and how the 10^12 + neurons in our brains create the individual person with unique learned and innate behaviors that we are.

 The brain is a phenomenal machine. It produces input, forms and conducts outputs, makes decisions, learns, behaves.....it does a lot of stuff. The brain is made up of many neurons, billions in fact; I would say that there is about 10^12 of them in all, and counting. And yes, while we are on the hot topic of behavior and the brain’s phenomenal ways of performing such behaviors, it does make sense that behavior is exclusively the result of the brain’s billions and billions of neurons. Perhaps, we can use this explanation to understand why one human being may perform a similar action as another human being, or why one ant would do the same thing that another ant would do. For example, I scratch my head when it itches just as if someone else would scratch their head if it itches. The neurons in both of our brains are telling us the same thing, "scratch your head!" If we both have neurons that control our behavior exclusively, than we would both do the same things in response to an input. However, let us think about such things as freewill, personality, and choice. If behavior was truly controlled by our neurons and our neurons only, would these aspects of our lives even exist? In this case, I suppose that we could use the excuse that the neural connections between neurons are what give us variability in decision-making. Instead of me scratching my head when itches, like my comrade just did, I pat my head instead. This model seems....ok. But something is missing. I just do not seem to be able to account for such things as personality and freewill. Variability in our neural connections does not completely justify these aspects of the brain, or should I say, the mind. If we were nothing but neurons and connections we would be more like robots, would we not?

Jayme E. Hopkins, '08

While I really enjoy this class, the vastness of the human nervous system makes me wonder what it can actually teach us, other than that the brain is far too complex to ever be minimally understood. Not only are there innumerable inputs and outputs that can occur in any given situation, there is no indication that there is any relation between them; that is, the same input repeated 3 times has the possibility of resulting in 3 completely different outputs. This is further complicated by the idea of “boxes all the way down,” especially due to the fact that no one knows what processes occur within the boxes, and how they affect the outputs. There are infinite combinations of inputs and outputs in the brain, which leads me to doubt that scientists will be able to do much more than scratch the surface when dealing with the functions of the brain.

Last week's discussion of the New York Times article on superstitious behavior and magical thinking got me wondering....

A Bryn Mawr alum friend of mine is going to have surgery soon to remove a part of a gland that may or may not be cancerous. But my first reaction upon hearing this was not to worry (although that came later); I thought immediately "I need to leave an offering to Athena for her!" What exactly would this offering to Athena do? Almost nothing at all from a medical standpoint; that's what the surgery is for, right? But from the perspective of a concerned and ultimately pretty powerless friend, leaving offerings to Athena feels like doing my part, however small.

And then I read the Times article. "Magical thinking"--behaviors like leaving offerings to Athena--occurs most often when people feel most helpless, it claims. So now my need to leave an offering makes more sense; because I can't do anything that would help in the medical sense now, I resort to superstition. But now, think about how superstitions and magical thinking are reinforced. You perform an action (like leaving an offering) once-the input. After you leave the offering, the desired event happens-you pass your test, your friend turns out to be okay-that's the output. Logically, there's no reason why adding the same input every time should lead to the same output. But you keep leaving offerings every time. If the desired event happens, your offerings helped. If it doesn't, then you may have left the wrong offerings, not left them soon enough-anything but the logical explanation.

This principle is called a variable schedule of reinforcement, and it's well known in psychology as a great way to enforce behaviors; among other things, it's what makes gambling so addictive. But I'm wondering if this principle can be applied to the nervous system too. The brain leads up to perform certain actions-inputs. Most of the time those actions produce one certain output, but in certain circumstances they produce others-a variable schedule of reinforcement. Because the actual output depends on a wide range of variables that we may or may not completely understand, we keep performing the actions over and over, hoping for the output we desire.

People talk so much about predictable outputs from certain inputs, but maybe it's the variable reinforcement that ultimately influences our behaviors more.

In the last class we discussed the immenseness that is the nervous system. It is made up for too many neurons to count--the number is most likely inconcievable.  We also came to the conclusion that since there are so many neurons there aren't two brains that could be identical.So isn't amazing that we are so much alike?With the infinite number on connections between neurons, we somehow manage to end up very similar to the person sitting next to us.  You can look at a picture of a bird and know it's a picture, not a real bird. I can do the same thing. We both have the same mechanism to perceive 3D from 2D.  And that is only one example of how my brain is similar to yours. Fun Fact (from Time Magazine 1/29/07): The genes used in the development and functioning of the brain in mice and humans are 90% the same.So this similarity is not only from human to human either.  So much brain research is performed on rats and other small mammals--and that can tell us about the human brain. Using the boxes within boxes model, this makes sense considering the smallest box we're considering is the same.Our differences are incredible, but it's the similarities that interest me the most.

The Science Times has become a lot more intriguing since I began taking this course!  This week, one of the articles I read was titled A Study of Memory Looks at Fact and Fiction.  The article was written by Benedict Carey and forced me to think about the models of the nervous system we described in class.  Carey writes about a recent study in which researches questioned the human capability to repress traumatic memories.  The researchers attempted to historically prove that the ability to temporarily forget certain memories is a “culture-bound syndrome,” rather than an actual neurological process.  These researchers, however, have been criticized for arriving at a conclusion before even beginning their study.  Other experts argue that there are in fact “real” cases of repressed memory both currently and that date as far back as to the days of the Greeks.This entire debate, often referred to as the “memory war,” has been revived as a popular subject of discussion due to the recent sexual abuse scandals between adults and children in the Roman Catholic Church.  Young, healthy individuals, prove to be a good example to demonstrate the link between trauma and forgetfulness.  Sexually abused children are often confused after receiving sexual advances from an adult they trust.  They may also be hurt, upset, and lonely.  These children’s brains often block their access to the painful memories, and then suddenly release them later in their lives. Whereas the brain will usually remember dangerous events, in order to prevent them from happening again, seemingly, it has the capability to break down memories that are too difficult to handle.  The brain, in effect, may have a built in survival mechanism.  In the article, this situation was explained as follows.  After an unwanted sexual advance, for example, a child may store this memory in a “neural drawer” with other confusing memories of youth.  Years later, the memory will surface, and the repulsiveness of the situation will be understood by the victim, thus causing an output of certain behaviors.This leads me to wonder about the Autonomy Model of the nervous system.  Although this model leaves room for inputs and outputs to not direct connect, and for living beings to react as they please, it does not explain suppressed memory.  How is it that one can have an experience, and then repress it rather than react to it until years later?  This is not simply a matter of forgetfulness, but rather a question of storage space.  Where do traumatic memories go for the periods of time when people block them?

In my Introductory Biology class, I read a section about the brain controlling which muscle fibers are stimulated in a muscle. One motor unit connects to the brain and to several muscle fibers within a muscle. When sitting upright, back muscles are partially contracted, meaning that some muscle fibers with in the muscle are not contracted while others are. The brain alternates activation among the many motor units that contract these certain muscle fibers. In doing so, the brain prevents muscle fatigue so that the organism can remain upright for a longer period of time before feeling fatigue. The organism, however, is unaware of the brain’s “decision” to alternate motor unit activation. In this case, output seems to be generated with no input. However, I propose that the brain creates an input for reasons unknown to the organism’s conscious mind, but known to the brain. This kind of internal reasoning or unconscious reasoning is the input that creates the output.

In the back muscle example, the brain is acting on reasons unknown to the conscious person. The person can’t feel the fatigue in their muscle fibers, yet the brain notices it and switches to different muscle fibers in the back.

In our class example of the cricket sometimes chirping when no female is presents, perhaps there is some other input in his mind that he associates with the female, hence the chirping. This input could be a product of conditioning, of anticipation, or of the unconscious. If the cricket chirps for reason’s that he’s unconscious of, it could be something his body is telling him or a prediction about what is to come. He’s consciously unaware of it, despite his brain's awareness. Could his mind and body be sensing something that he isn’t aware of? Is the unconscious a type of input that conveys an output?

Learning about the different ways of perceiving the nervous system seems to have led me back to Emily Dickinson. I think if Emily Dickinson had known what we now know today she wouldn’t have been in the least surprised. The fact that the brain can produce outputs without any external inputs would not, I think, surprise her. If we believe Emily Dickinson to be right, if everything we perceive is just a function of the brain, then really there should be no difference between external and internal inputs. What the brain perceives and what the brain thinks it perceives is one and the same. It explains why the leech nervous system can think it is swimming when it is detached from the actual leech and no outside stimulus is possible. It explains why you can wake up from a nightmare with your heart racing and cold sweat pouring down your neck in the same way it would if you had really just been pursued by some terrible entity. So perhaps, the great poet is right. Everything is just a function of the brain. To the brain the dream is just as real and just as significant as physical outside input. I’m not sure if I believe it entirely. However I am slowly realizing the grandeur of the idea.

In the introduction to the postings for this week Professor Grobstein is “looking forward to seeing what is on our minds this week” but after the discussions in class this week I am inclined to suggest changing that to what is on our brains.

In class we talked about when the nervous system of the leech was isolated from the rest of the body, it was still able to create a pattern of output similar to that emitted of when a leech is swimming. My interpretation of this is that there are systems pre-programmed into different regions of our brain, which are in control of our behavior. These are the little boxes that make up the big boxes which are able to create output without input. This to me is in support of the brain=behavior theory. If we have all these little boxes full of pre-programmed functions, all we need is a  big box of executive function to control which boxes are activated and when.

Some might argue that this executive function is the mind, but I think this executive function resides within one of the big boxes of the brain as research has shown perhaps in the frontal lobe as found from observations of frontal lobe damaged patients. One especially famous example in the psychology classrooms is Phineus Gage. After a rod shot through his frontal lobe, the connections from that box to his other boxes were disrupted, and he no longer produced the same outputs or behaviors. His brain was damaged, his interconnections between boxes were disrupted, his behavior changed proving brain = behavior, to me it is as simple as that.

Getting back to the outputs generated without inputs, it is important to question what is being taught to us and we might say, so what, a nervous system from a leech was able to generate outputs without inputs resembling swimming patterns. How transferable are observations from a leech brain to the human brain, after all they’re way of having a good time is sucking blood. Most of us probably behave very different from leeches and thus have very different brains.

 But this is definitely a start and also not the only thing able to generate outputs without inputs in vitro. The hippocampus, a part of the brain involved in consolidating memories and spatial navigation, can be isolated and kept alive in vitro apart from the rest of the brain. It is still able to perform its function of learning. Through instrumental conditioning, you can train slices to increase or decrease their rate of firing by rewarding them with dopamine. It can be trained to repeat that pattern of dopamine in expectancy of reward. This is an example of one of the boxes that is able to retain its pre-programmed function of learning apart from its connections in the brain, and also this hints at the analyzation abilities of the boxes. These observations can be made from slices in the rat brain, which is somewhat similar to the human brain and also add further support to the leech nervous system example suggesting pre-programmed systems in different parts of the brain.

In sum:

After learning about leeches in vitro, reading about the hippocampus in vitro, and remembering Phineus Gage, I think the brain has pre-programmed systems in different parts of the brain, which are activated from interconnections between all the parts of the brain and an executive system also in the brain. I am even more a believer of the brain being filled with interconnected boxes theory, and brain=behavior.

In class, we briefly touched upon the subject of morality and I think it is an important subject to discuss seeing as how it is very pertinent to our daily lives as we encounter the Honor Code everyday.   I think it was Rebecca who defined morality as avoiding harm from coming to you and to others.  As we established in class, it is also a socially constructed idea and it is taught through interaction with others.  I agree with the both these points because a baby isn’t born with a sense of right and wrong.  The concepts of what is right and what is wrong are taught to us through school, our upbringing, and other external influences.  My perception of morality seems to be changing the longer I am at Bryn Mawr.  Prior to coming to college, my morals were relatively similar to those of my peers and I conformed to their ideas of what was right and wrong because they were my primary influence.  Now that I have come to a college that promotes a new way of thinking from one that I was used to in high school, I feel my morals are slowly evolving and becoming more specific to my new lifestyle.

Usually I wouldn't search TIME Magazine for good scientific articles, but an issue from a few weeks ago has an entire section called "The Brain: A User's Guide." All of the articles were fascinating and in very easy-to-understand language, but one that stood out to me was entitled "How the Brain Rewires Itself." The author described an experiment done by neuroscientist Alvaro Pascual-Leone where he first took a group of subjects and had them practice the same piano excercise for five days. Then he took TMS tests (transcranial-magnetic-stimulation test) which showed the function of neurons being tested. In this case, it demonstrated that the part of the motor cortex that was in charge of dealing with these piano-playing finger movements had taken over surrounding area in the five days of practicing.

But the most interesting part of this experiment was in the second group he tested. In this test, instead of actually practicing PLAYING the paino, he has his subjects THINK about playing the piano for the same amount of time as the first group for five days. They were to visualize moving their fingers in the same way the first group would have, just without real movement. When he did the TMS test on these people. the results were surprising: the part of the motor-complex that controlled the finger movements had once again expanded and taken over adjoining areas of the brain.

In class the other day we talked about whether or not just htinking could actually change the structure of the brain (aside from consolidating memories, etc). This is proof that indeed, it can. In my opinion its a fascinating, but somewhat terrifying thought. What if you unconscoiusly are thinking of something enough that it changes the structure of your brain without your knowing? Is it possible for unconscoius thoughts, like dreams for example, to do this as well? If so than our minds and behavior could change without our even knowing it. It would seem that we have much less control that we may have thought we did. Its seems in this article, that Emily Dickinson is indeed right: we are a product of the brain as opposed to the other way around.

After class I was searching the New York Times achieves and found an article that interested me.  Initially, I did not think it pertained to class discussion but found it so fascinating that I decided to read it anyway.  The article was about a disorder called pseudocyesis.  According to the article, this rare phenomena causes women to display practically all but three symptoms of being pregnant.  The only symptoms not displayed are heart tones from the fetus, visual representation of the fetus on an ultrasound, and the actual delivery of the baby.  However, women have experienced cessation of their menstrual cycle, morning sickness, enlarged belly, cravings, enlarged and lactating breasts and some even test positive on pregnancy tests. 

Physicians and psychiatrists have suggested that a woman’s extreme desire to have a baby of her own, or even to play a larger role in another’s pregnancy, can cause these symptoms to arise.  Yet, others have established that there are a variety of emotions that might spark the phenomenon.  When I read this, it reminded me of the short comings of the spaghetti box model of the brain.  If “stimulus A” is the desire to have a baby and every time “A” is stimulated it results in “response A” which is developing pseudocyesis then why is this condition so rare?  If there were the case then I should have experienced pseudocyesis about 100000 times because every time I see a happy couple with their baby at Starbucks or in the park etc. I get the desire to have a baby ( but then I quickly wipe that thought out of mind!)…Anyway, you get the idea.  The stimulation of “A” CLEARLY does not always lead to “response A” or pseudocyesis.  Similarly, “stimulus B”, anxiety, has also been found to result in “response A”.   

At the end of this article, a doctor is quoted as saying, “The pituitary gland is located right at the base of the brain, and that’s where all the hormones come from” in pregnancy, he said. “This is one of the classic examples in medicine of how the mind affects the rest of the body.”  Although I may just be being picky, I think that the doctor used a poor choice of words.  Brain, would have been a much better word to convey the message that he was trying to get across because he is attempting to explain the body’s response ( or behavior ) to an influx of hormones in the BRAIN not the mind.  I suppose that if one believed in something called “mind” that it could be responsible for the desire of other emotion that triggers the brain to produce an improper amount of hormones, but that’s a very roundabout way of saying it and I doubt that anyone understands what I’m trying to say here (Ugh!).  I have more to say about this and how it related to class but I need to think about it a little more before I actually write.  I just wanted to throw this topic out there for discussion because I found it so bizarre and thought that many of you would be intrigued as well.

            And one last thought:  What is perception’s role in this phenomenon?  If people did not perceive the “pregnant” woman as being such, would she go through the 9 months of symptoms and try to deliver or would her feelings subside without positive reinforcement?