Neurobiology and Behavior, 2000, Topic 6

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An ongoing conversation on brain and behavior, associated with Biology 202, spring, 2000, at Bryn Mawr College. Student responses to weekly lecture/discussions and topics.

TOPIC 6:

Knowing something about neurons helps to make observations which characterize properties that emerge from organized collections of neurons, such as "motor symphonies", "central pattern generation", and "efference copy (corollary discharge)." In what ways do these help one to better understand behavior? What new possibilities and questions do they in turn raise?

Name: rebecca
Username: rjones@brynmawr.edu
Subject: feeling like it
Date: Wed Mar 8 10:19:59 EST 2000
Comments:
In class we discussed the teh separation of the nerve system from any imput and the symphony generators in the nervous system. In class we had an issue with the lack of repeatable results in the experiment. Your explanation of the use of electric current or chemicals being applyed to the environment making the neurons want to do the looked for behavior gave me an interesting idea.

Cristopher Reaves can't walk or use his lower appendages because they are not getting the imput they need to move. We talked about the difficulty of reconnecting the spinal cord and brain which makes the possiblility of him ever walking pretty much nill. However, the concept of neral syphonys being stored in the nervous cord and not just the brain and the fact that feed back is not necessary for movement gives an alternative. What could be done is to attach a device to the nervous cord that delivers electricity or chemicals (what ever makes the nerves in the spine feel like making movement) to enable him to wake. The device could be audio controled so that in a round about fashion commands in the brain could be directed to the

Name: Paul Grobstein
Username: pgrobste@brynmawr.edu
Subject: week 7
Date: Thu Mar 9 09:38:06 EST 2000
Comments:
Hope everyone is having a good spring break ... AND thinking about how the brain works and what that has to say about behavior. Glad Rebecca is. So, we need a topic that she fits into. Not so hard, since she was clearly thinking about things we talked about last time we met, remember? How about:

That's just to get your mind/brain oriented back to where we were when we last talked (if you needed it). Take any part of the question you're interested in, or, as always, write about anything else that's been on your mind. Of yeah, the last set of forum comments has, as usual, been moved to their own file.

Name: Maria
Username: mvasilia@brynmawr.edu
Subject: Symphonies
Date: Sat Mar 11 20:48:10 EST 2000
Comments:
Interested in the metaphor we are using of “motor symphonies”, I thought I would read up a little about symphonies and what “movements” actually entail. I played piano for almost nine years, but was never really paying attention to what my music teacher was telling me. I now realize that a symphony by definition is a large-scale musical composition for an orchestra. Symphonies are divided into sections called movements. That is where the “word” comes into play. Most symphonies consist of four movements, but some have only one and others have as many as six. The first movement of most symphonies is moderately fast. The second movement if the slowest, and the third has a dancelike quality. The fourth movement is a lively or triumphant conclusion. This is really interesting and I now realize how fitting this musical description is. When we equate behavior with a “motor symphony” each motor neuron generates different patterns and the combination itself constitutes behavior. These motor neurons relay instructions form the central nervous system. And the sensory sense organs have special sensory neurons call receptors. We discussed these receptors and realized that they translate information about the internal and external environment into nerve impulses. These impulses are electrical signals that nerves can carry. This becomes interesting when we talk about Christopher Reeves and the idea of our brain as a computer with preexisting programs. Christopher Reeves knows how to walk, how to move his leg, but he can not. If we take an electrical wire and shock Reeves’ leg muscles will we get movement, yeah, but his brain can not send the message down to his leg. Well how about if Reeves’ leg goes for a long time without any movement and with out any stimuli. What will happen? Then the leg will not be able to move and the behavior he once knew will be gone. I mean why do we do physical therapy? Because if we don’t use it we loss it, movement that is. So behavior can be lost. How fitting the use of “motor symphony” is, since the triumph in most cases does seem to be at the end, but the beginning and middle have a lot to do with the process.

Name: Melissa
Username: mwachter@haverford.edu
Subject: something different
Date: Sun Mar 12 20:06:04 EST 2000
Comments:
I am going to break from my traditional approach to writing in th forum area. Usually I pretty much give my take on the question of the week and comment on other people's comments. Instead, I am going to diverge off of the topic and write about some of the things that have been on my mind...Over spring break I began to read a book by Larry Dossey entitled "Healing Words- The Power of Prayer and the Practice of Medicine". Now this guy is not just some religious quack, he is an M.D. and health guru Dean Ornish writes of the book " The most thoughful, eloquent and interesting book on prayer, health and healing that I have ever read". Now I have so far only read about 50 pages of the 400 page book so I do not promise a complete review...mostly I want to concentrate on giving more description of the study that I mentioned in one of my early postings and note some of the interesting points that he mentions that might be relevant. He argues that prayer can affect our health and that this phenomenon cannot be completely explained by the placebo effect. He argues that prayer is a "nonlocal" event in that it is "not confined to a specific place in space or moment in time" (p8) He describes a number of studies that give empiracal evidence for prayer's power, which is then, "indirect evidence for the soul" (p9) An example is the study that has come to be known as the "San Francisco Prayer Study". Before describing the study let me just say that Dossey generally argues that there is power in prayer beyond the placebo effect as shown by finding that there is positive effect of prayer in mice, chicks, fungi,and bacteria which do not "think"in any conventional sense and are presumedly not susceptible to suggestion.

Alright now for the study...a computer assigned 393 patients admitted to the coronary care unit at San Francisco General Hospital to either a group htat was paryed for by home prayer groups or group that was not remembered in prayer. The study was designed with strict criteria (randomized, double-blind) and neither the patients of the doctors/nurses knew whcich group the patients were in. The prayer groups were given the patients' names and a brief description of diagnosis and condition. They were told to pray every day, but no explicit directions about how to pray were given. It was found that the prayed-for patients were 5 times less likely to require antibiotics, none required artificial airways (compared to 12 in unremembered group), and fewer patients in the prayed-for group died. There were definitely critics of the study, but many of the challenges have been confronted and the study has been repeatedly done with the same results...AND THIS CAN"T BE THE PLACEBO EFFECT B/C THEY DIDN"T EVEN KNOW THEY WERE BEING PRAYED FOR...for those that are interested, the study was by Randolph Byrd in the July 1988 edition of Southern Medical Journal...though i think that it was repeating sometime within the last 5 years in a more reputbale

Name: Stephanie
Username: swall@brynmawr.edu
Subject: beethoven's fifth
Date: Mon Mar 13 15:17:12 EST 2000
Comments:
I think using the concept of a "motor symphony" gives us the best analogy yet for behavior. More technically, we are now saying that behavior is a complex spatial/temporal pattern of action potentials in motor neurons. The motor symphony analogy helps to capture what I was trying to say earlier in the forum when I said that the brain, or central nervous system, is more than the sum of its parts. A symphony is a collection of musical notes played by many different instruments. The notes for a particular instrument will produce a much different sound when played alone than when played with the other instruments. Taken together, the notes from each individual instrument produce a collection of sound that is not found on any one sheet of music. Just as a symphony is greater than the sum of the individual notes from the individual instruments, behavior is more than the sum of individual action potentials from individual neurons. The output/behavior does not "exist" in any one element or signal but in a pattern of activity across a very large number of signals.

The 'motor symphony' analogy leads us to an interesting analogy for brain malfunction. If any one neuron "misfires", this can mess up the entire symphony. Or it could have no effect at all as it is 'absorbed' into the larger pattern of action potential, just as a wrong note from the cellist can get lost in the symphony. How do we know which neuronal 'misfires' will be detrimental and which will be harmless? What about solos? Is it ever the case that particular neural pathways go solo (producing action potentials and thus motor output) for a time? Maybe an analogy for soloing is the "labelled-line" coding (such as the optic or olfactory nerve) where the significance of a signal depends of the line carrying it.

I think the motor symphony analogy complicates our model of "boxes within boxes" in that it distorts the connection between input and output. We now know that there is not a single cause (input) for a single effect (output) in the nervous system. So we must ask, what causes a particular pattern of action potentials in motor neurons? And how can we trace an output to any input? Experiments have shown that a central pattern generator, or "score", exists prior to motor output, and also that the nervous system modifies motor output based on sensory input. I am not satisfied that the CPG is a distributed system, with no specific location. I would have assumed it must be located in the brain, but experiments don't seem to support that.

Name: Vandana
Username: vandnam@yahoo.com
Subject: in response to prayer
Date: Mon Mar 13 16:44:24 EST 2000
Comments:
i was reading over the weekly essays and i was really interested in the study that melissa mentioned. it's amazing that the subjects who were prayed for did not need antibiotics and few of those patients died. this is similar to what i am learning in one of my other classes. over break, i read a book by vasant lad called "ayurveda: the science of self healing." ayurveda is an ancient science of healing in india. i also saw a video in which vasant lad, an ayurvedic practioner, mentioned that chanting hymns and meditation can help in self healing. he described how you can create your own reality by changing the way you think, which results in a change in the way you feel. i think that it is really important that today, people are returning to the notion that you can be your own doctor and that changes in lifestyle can change the way you feel and bring improvement in life.

in response to what we have been discussing in class, i agree with stephanie and maria that the "motor symphony" is a good description of the way the nervous system works. it tells us that movement is made up of sequences of action potentials that occur in many neurons. i think another way that movement can be described is to think of a crowd cheering for a team. without the people in the crowd, you cannot hear the cheers (just like without specific neurons, you cannot act). i think rebecca's idea of a device for christopher reeves, that provides chemical signals that can be stored in the spinal cord, is a really good one. i do not know how feasible it would be to make one.

Name: hillary
Username: hbobys@haverford.edu
Subject:
Date: Mon Mar 13 17:52:16 EST 2000
Comments:
ok, so i was home over break and i went to an aerobics class. kickboxing. it was unlike any other kickboxing class i had ever been to and about 20 times the intensity of the normal class. i hadn't eaten breakfast and after about 15 or 20 minutes, my vision started to go. things were fuzzy and grey. i felt sick to my stomach and my hearing was off. after i rested for a bit, i realized i had just stumbled across a topic for my next web paper and a good example of a motor symphony.

my body had little fuel to go on and little oxygen, i suppose, although i did not feel out of breath. my sight, hearing, and visceral organs were all affected by this lack, resulting in a coordination of many sensory responses all at once. i think stephanies questioning of whether a "misfire" can cause an interruption of the entire system, or whether it is absorbed by the huge number of other neurons firing. it is within examples of neuron damage and imaging (and almost fainting) that we are likely to find answers to such questions.

Name: Laurel E.
Username: ledmunds@brynmawr.edu
Subject: no comment
Date: Mon Mar 13 20:13:23 EST 2000
Comments:
While I have maintained all the while that brain and behavior are the same (really, I have) it is comforting that we’re uncovering more detailed, logical explanations for why this is so. When we were focusing on the myriad of salt water bags that behave exactly the same way in the body by carrying identical action potentials, it was difficult to explain the endless variety of distinct behaviors displayed by humans and other animals. The missing link, that where neurons terminated influenced behavior, was significant. Then, we encountered the motor symphony concept, which aside from being pleasingly poetic, is also helpful in understanding the complexity of behavior. For one, as I think Stephanie mentioned, there is less opportunity for devastation if one neuron misfires or fails to fire at all. As in large symphony, a couple of botched notes on one violin will most like not affect the total sound. Since we’ve said that behavior can’t be traced back to a single input/neuron, I doubt any renegade soloists could jeopardize the health or proper functioning of the nervous system as a whole.

I found the earthworm and crayfish experiments to establish CPG interesting. However, they do seem very limited in their applications, since we obviously can’t perform similar experiments on humans. How can we relate these results to patterns of human behavior? Is all of our behavior regulated by the “write while performing” theory? Or do we display some that follow the CPG “score”? And what is it exactly that serves as feedback to other neurons as we display a certain behavior or go through certain motions? Can we say for example that the production of endorphins from laughter or physical exertion perpetuate these behavior that create them initially? I’m a bit lost here…Perhaps we discussed this the day I missed class?

Name: Cameron
Username: cbraswel@brynmawr.edu
Subject: The patterns
Date: Mon Mar 13 20:53:53 EST 2000
Comments:
At the risk of sounding redundant I too would like to comment on some of the things said in the forum area this week. It seems several comments are related to do we have certain pre set patterns in our brains that channels of neurons follow or do we write them all as they happen for the first time. Do our brains use a mixture of both. How long do we store these patterns once they are written? (this has to do with what someone said about if we stop using the pattern will it eventually be lost?)If Christopher Reeves were suddenly able to walk, play kickball, dance etc. would his motor pathways remember how to. Obviously he would need physical therapy to regain his strength and stamina for such tasks but at the same time does the physical therapy also rebuild the patterns once in his nervous system that have fallen by the way side. In respect to motor symphonies physical therapy could be like rehearsing an orchestra after a long break on a piece that has previously been played but is now a little rusty. Reminents of how to play the piece are still there (previous pattern) but the act of putting all the instruments together (neurons)to play an old piece (previously learned action) needs some fine tuning to get it right. This would suggest that physical therapy is needed as much for the brain as for the body to build up both areas. Thinking about all this seems to support the continual use of a CPG to display a behavior just as a motor symphony is correct becuase no one neuron can carry a particular behavior. and it would indeed lead me to believe that "outputs" can be "inputs" if the stored pattern goes in the opposite direction.(therefore "input" really can come from anywhere in the box as long as the pattern is followed.) I have not been convinced by anything that there are preset patterns in humans. But of course it would depend on where you defined preset; at birth or at conception or somewhere else? If the "scores" start before we are born (which I am convinced of) and the starting point is defined at birth then yes there would already be some patterns stored for continual use but as the brain is forming cell by cell is it already setting up sequences and patterns that will be motor symphonies of various "genres"? I am not sure and I am hoping it is a qustion we can answer.

Name: Elissa Braitman
Username: ebraitma@brynmawr.edu
Subject: (post-break)
Date: Mon Mar 13 22:38:59 EST 2000
Comments:
Although I don't feel that I have anything exciting to add to this week's postings (still trying to get used to being back here), I have learned/ been reminded of things by other people's entries.

Maria's definition of a musical symphony was extremely helpful in visualizing one of the motor variety.I also found her comments on physical therapy interesting. I had never thought about it in that way.But it makes sense that muscles (and the neurons controlling them) must be reminded of how to achieve certain types of movement.

I was also intrigued by what both Laurel and Stephanie said about the absence of problems associated with the misfiring of one or just a couple of neurons. That's also logical since behavior is the result of the firing of many neurons, not just one or two.

Name: Laura
Username: lchivers@brynmawr.edu
Subject: symphonies
Date: Mon Mar 13 23:00:02 EST 2000
Comments:
I really like Stephanie's way of looking at motor symphonies. We all know that killing a few neurons (say through a sip of alcohol) doesn't change our behavior in a noticeable fashion. This seems like Stephanie's idea in that a missed note by one cellist may be unnoticeable if it is played by another cello as well. PErhaps we notice no difference when one cell is killed because another is playing the same "note" note in the motor symphony.

I also liked her idea of solos. However, I think it depends on our definition of sole. If a solo is played by only one player, or only one nerve, getting rid of that one player or one nerve is not difficult, and it seems that this could not be the case in our brains, as we know that many neurons make up the nerves that have one main function. If only one neuron was responsible for sending mesages to the optic area of the brain, many people should be unable to see since their one neuron would be so easy to kill. However, if we view the solo as a solo by a section, say the violins or the optic neurons, I think the idea is well applied. Like in the case of the one cellist missing her note in the symphony, a missed note by one violinist or misfiring by one neuron should be barely noticeable, if noticeable at all. But poor playing or no playing at all by half of the violins or the same for firing in half of teh optic neurons would surely be noticeable, and in some cases may even render "discordant" both types of symphonies. Thus I feel this idea of "solo" is helpful for understanding the nervous system.

Name: christina
Username: cpili@haverford
Subject: motor symphony questions
Date: Mon Mar 13 23:53:27 EST 2000
Comments:
The image of a motor symphony really helps me understand the configuration of the NS. But after reading some of the postings, I have questions concerning the notion of solos. Is it really possible for a solo to occur? In the event that a solo neuron malfunctions, we can say that due to homeostasis, the whole symphony would not be off beat. So within this symphony, does every soloist have an understudy. If this is the case, would the output result in a longer response time because we have to consider the lapsed time from the malfunctioning soloist? Or does the understudy and soloist perform at the same time?

How is it decided which symphyony plays? How does the NS limit or choose which pathway is the most effective? Is it not necessarily the shortest path? Or are multiple symphonyies "playing the tune" performing in case that one of those systems breaks down?

Name: hiro
Username: htakahas@haverford.edu
Subject: symphony analogies
Date: Tue Mar 14 09:41:26 EST 2000
Comments:
i would like to use the analogies of orchestra symphony, too. as someone has already mentioned in the forum, the symphony works as a collection of many different instruments. If someone plays a wrong note, then the orchestra as a whole will produce an unpleasant sound. For example, if the mistake is very big, like all the violinists are on the different page from everyone else, or the triangle plays at the wrong timing, most of the audience, who knows how the symphony supposed to sound, will realize that there is something wrong. Contrarily, if the mistake is very small, like only one of the 20 violinists plays one key higher, the audience may not hear it at all. However, the experts in the audience and the conductor probably can pick up even the smallest mistake.

someone has mentioned that the small "misfiring" of neurons may be absorbed and may not appear in the overall behavior, but i think the mistake somehow shows up. many people may not notice it if it is an insignificant mistake. However, like the experts and the conductor of the symphony, the experts in neurobiology and behavior may notice a very small miscordination of one's motor activity. Let's say that the "misfiring" of a neuron is eliminated by inhibitors sent from brain and does not affect behavior at all. This is like a very unskilled violinist or cellist with an injured finger; he "gets cut" from the orchestra and does not even take a part in the symphony at all. He may be replaced by someone better. (Can the function of neurons be replaced, too?)

also, like the conductor of the orchestra, the nervous system needs something like a coordinator for the motor symphony to take place. what would that be? since both the performers and the conductor are humans in the orchestra, i assume that the "coordinator/leader" in the motor symphony to be a neuron, or rather a set of neurons, too. the organization of these neurons must allow them to sense what is going on in all the neurons in the body, send them signals, and lead and control all the neural activities and behavior. i also believe that this function would be somewhere in the brain, maybe hypothalamus. but, how does it have to be organized to produce a perfect motor symphony?

Name: Andrew Jordan
Username: ajordan@haverford.edu
Subject: something not so related
Date: Tue Mar 14 12:49:51 EST 2000
Comments:
OK, this is not really 100% related to anything which has been said above which is all about motor symphonies an pattern generators and such, . I was writing the first draft of my philosophy thesis this past week, and i was thinknig about how there are very distinctive ways in which we are conscious. Now, obviously the central pattern generator view does not mean that we don't also take in other bits of information from the environment which then cause alterations of our behavior. We may have a central pattern for walking, but in order to walk we need to respond to our envirnoment. We were talking today in class about whether Central pattern generators were learned or whether they were genetic. Now, obviously the ability to walk is something that is common presumably, to all humans in all historical epochs. However, something like driving a car is not. Could there be a central pattern for driving a car for instance, and if so, would this be a good indication that at least some central patterns are learned. The reason why i was led in this direction, is that as i was driving to bryn mawr one day it occurred to me that from the moment that i got into my car, til i stepped out, i hadn't really been paying attention, actively, to what i was doing. Now obviously, there was imput from my envirnoment, or i would have gotten into several wrecks. But all the same, i kind of just found myself at bryn Mawr. This made me think about what seems to be two different levels of awareness, one which is active and one which is passive, and leads me to ask what changes physiologically speaking, when we are actively engaging the world instead of just passively responding to our environment.

Name: Cruz
Username: rcruz@haverford.edu
Subject: Auto Symphonies
Date: Wed Mar 15 21:07:39 EST 2000
Comments:
Cars have been on my mind a lot lately - for both good and bad reasons. My car broke down on my way back from the break and I saw the movie Ronin which has some breathtaking car chase scenes.

First, as I looked over my engine, and thought about what could possibly be wrong. I knew that the battery was fine, so some connection must be broken, or some relay switch got crossed. Sound familiar? My problem was that the starter was not getting any juice, so the "motor symphony" of engine start and engine running could not get started. An essential link was missing. The electricity was there, but had no conduit.

As for Ronin, I was amazed at the quickness and automaticity that the stunt drivers displayed. I read that most of the drivers were veterans of the famous 24 hour race in Le Mans France. In one scene the two chase cars weave in and out of oncoming traffic in tunnels and narrow highway for about 3 minutes. They had to react without even thinking about it - because there simply was not the time to do so. I'm assuming that most of you can drive, so you know how you move from having to think about every action (signal, mirror check, blindspot check, move over to other lane) to driving long distances with hardly a thought. How do these orchestras work, and how do they change with experience. Is it just a strengthening of chemical signals, or do neurons actually rearrange themselves into a more efficient pattern (we only began to see how many different ways even a simple "piece" or "movement" can be arranged).

Name: Andrew
Username: aholland@haverford.edu
Subject:
Date: Wed Mar 15 23:48:56 EST 2000
Comments:
I guess I am a little late writing this week….Anyway, here are some of my thoughts I had over break about the brain and the nervous system. A story on Twenty/Twenty Click here for the story on ABC's website caught my interest. The program was about Chronic Fatigue Syndrome. Healthy, active people began to feel tired and constantly in pain. Many doctors said that there were no medical problems and the symptoms were psychological. Some of these patients found relief after years of suffering through neurosurgery. MRIs have shown that the opening at the base of the brain is sometimes too small and compresses the brain as it narrows to become the spinal cord. Neurosurgeons operate and remove some of the bone at the base of the brain so the spinal cord or brain is not compressed. These procedures are experimental, but some people have reported positive results and a return to their previous quality of life. So what does this mean? Perhaps the nervous system is greatly affected by the bones that surround the central nervous system. Maybe other conditions stem from similar circumstances. Basically, I am wondering about how the skeletal system impacts the nervous system.

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