Forum Archive - Week 8
We've discovered
- sensory inputs of which one is unaware
- that the nervous system embedded in a reafferent loop, so that its outputs affect its own inputs
- central pattern generation
Which of these change (or seem likely to change) how you think about behavior and why? What new questions do they raise?
Name: Paul Grobtstein
Username: pgrobste@brynmawr.edu
Subject: getting there?
Date: 2003-03-22 15:55:44
Message Id: 5130
Comments:
Whatever last week made you think about ... as always. Including the attack on Iraq, though that might get a broader audience if you post it in The Place of the US in the World Community.
If you need something neurobiological to get you started, how about:
We've discovered
- sensory inputs of which one is unaware
- that the nervous system embedded in a reafferent loop, so that its outputs affect its own inputs
- central pattern generation
Which of these change (or seem likely to change) how you think about behavior and why? What new questions do they raise?
Name: Lisa
Username: RoxyQ770@aol.com
Subject: conjoined twins
Date: 2003-03-22 20:23:05
Message Id: 5133
Comments:
i have a psychology paper due soon and it is on conjoined twins. i have found countless amounts of website pertaining to thier physical development, but what i need now i any information on thi cognitive growth and develpment. can anyone help me locate this information?
Name: Amelia
Username: aturnbul@brynmawr.edu
Subject:
Date: 2003-03-23 20:44:52
Message Id: 5138
Comments:
The fact that we have sensory inputs that we are unaware of makes a lot of sense to me now that I think about it. If we had to consciously think about everything our body does, or if we knew everything that our body was doing, I think that we would have problems functioning with anything outside of all that we would have to do to keep our bodies functioning. I think that if we were actually knowledgable of all of the inputs which our nerves were taking in we would suffer from information overload. I think it is our bodys' way of allowing us to function; since we don't need to know that a certain nerve is firing in the small intestine to tell a muscle to contract so that food can be transferred to the large intestine, we don't recieve the input that the nerve is firing.
Name: geoff
Username: gpollitt@haverford.edu
Subject: proprioceptors
Date: 2003-03-23 21:14:30
Message Id: 5139
Comments:
Something is missing in my conception of what proprioceptors do. I understand that there is a whole section of our nervous system that is responsible for internal functionings, rest and digest (sympathetic?), but i feel like proprioceptors are more than that? so what are they?
professor said that they give us a sense of ourselves in space. the example was of picking up the mouse with his eyes closed. i don't buy it, and i don't think we have a very good sense of ourselves in space without our normal sensory inputs. picking up the mouse is a function of memory, and maybe the central pattern generator, which makes sense to me. but if one of us had to get up from our seats and walk across the room to pick up the mouse, we would have a hard time. how well we did would depend on the sensory input we were able to gather along the way (in addition to the initial memory of the room's layout): the slope and texture of the floor, maybe the sound of the students or computer, even the air brushing by our skin giving us an idea of velocity. i don't think we would have very much idea of where we were outside of these things.
what i was thinking about when professor was picking up the mouse was how, when you turn the light off in a room and move around for a few minutes in the pitch black (before your eyes adjust), you make all kinds of mistakes that my idea of proprioceptors would not allow. your steps are too small, even though your body tells you they are bigger, and when you go to stretch out your arm to touch a wall, if you can't see its outline, you will usually be way off as to how stretched out it was. when you touch the wall you realize you hadn't actually stretched out your arm at all, though your assumption was different.
so what exactly do these guys do? does it just take practice to get them into use? i understand the idea of a loop that helps the body make use of the senses it has and provides us with smooth, continuous movement, so is that all they are, a mediator between the sensory and motor neurons? i understand that they do not give a sensation, but i don't understand what they are giving me since my automatic assumptions about my body when i am not able to key in on other senses are usually way off.
Name: Alanna
Username: ajalbano@brynmawr.edu
Subject: forum 7 question
Date: 2003-03-23 23:26:04
Message Id: 5140
Comments:
No! Physiology alone is NOT ENOUGH to explain all of human behavior and experience. Yes, we have discussed how the intricate makings of action potentials, neurons, and the like have a huge impact on our behavior -- we have also discussed how disruptions in the physiology are likely to lead to abnormalities in behavior. However, we still have not discussed and accounted for changes in behavior that CANNOT be attributed to any sort of physiological mishap. Therefore, there must be something more going on inside the brain -- I don't know exactly what it is, but I do know that it is something that is neither tangible nor physiological. How do you account for the "soul" or "free will" physiologically in terms of brain and behavior? The point is: you just can't. I don't think it possible. Our inability to completely understand the inner workings of the brain, those that cannot be studied under a microscope, stands in the way of being able to explain what lies beyond the physiological.
Name: Annabella
Username: arutigli@bmc.edu
Subject: Free will
Date: 2003-03-24 00:23:34
Message Id: 5141
Comments:
While I agree with the statement that 'physiology alone is not enough to explain all of human behavior and experience,' I cannot find the thread that joins it to the idea purporting that it hinders our ability to 'explain what lives beyond the physiological.' If we can explain what exactly our physiological processes do, then we have narrowed down a wealth of things that our free will is NOT accountable for. Using our research and acquired knowledge to sieve through human existence, we will have a much clearer idea of what free will IS accountable for. However, this is not something that can be accomplished in a single college class. This class is the stepping-stone that will help guide us towards a lifetime of questions—and eventually an answer. Before we ask the question, it is imperative that we define what free will is, and then ask, "What is free will?"
A quote to remind us all to be careful in our reasoning.
Reasoning is full of tricks
And butterfly suggestions,
I know no point to which she sticks;
She begs the simplest questions,
And, when her premises are strong
She always draws her inference wrong.
- alfred colchrane
Name: marissa
Username: mlitman@brynmawr.edu
Subject: without senses
Date: 2003-03-24 15:51:48
Message Id: 5146
Comments:
Geoff's point about not being completely aware of oneself regardless of proprioceptors made me wonder about what happens to proprioceptors when a person loses one of their senses. For example, when someone becomes blind or deaf at some point in their life, they adapt to their new situation and are able to utilize their other senses still available to them to a much greater extent. Does that mean that their proprioceptors are more activated, and that those of us with all senses just do not utilize them to their greatest capacity, or is this an entirely different function within the nervous system?
Name: Laurel
Username: ljackson@brynmawr.edu
Subject: Uncomfortable Chair
Date: 2003-03-24 19:21:35
Message Id: 5149
Comments:
During class on Thursday, Professor Grobstein made the point that none of us was aware of the sensory receptors in our "derriere" sending messages to our brain until he mentioned that they were doing so. What is the importance of not realizing them? We can't be aware of everything at once. Such obsessive behavior can hinder quality of life. There is such a thing as a neutral existence in which we don't care about the chair in which we sit. Although the sensory receptors are sending the information, it's not something that triggers thought unless it differs from the neutral state -- if the chair is particularly comfortable, we might realize it, or if the chair is particularly uncomfortable we will most likely realize it, and shift until we find a position that is closer to neutral. As I ruminated on this, my thoughts shifted to habit. It's odd how certain behaviors are so commonplace that they seem almost unconscious. Can such habits become a product of the nervous system not triggered by external stimuli?
Name: Cordelia Stearns
Username: cstearns@brynmawr.edu
Subject: free will
Date: 2003-03-24 20:59:11
Message Id: 5152
Comments:
I guess when I break free will down to its bare minimal meaning, I think of it as the ability to choose not to do something one is physically capable of doing. When I think of it that way, I come to the conclusion that it must not take some extraordinarily magically complicated system to produce free will. Infants have free will: they can refuse to suck if they are not hungry. My dog has some types of free will: when he sees a deer, he chases it...when my family goes on vacation he'll chew something to get revenge. And yes, I guess I believe that computers and machines can have free will, though I don't think the one I'm typing this on does. Maybe even it does, in its own way. I guess I think there are some limitations on free will in everything that posesses it....maybe the name free will is misleading. I think that one of the reasons it is hard for us to concieve of free will being constructed of neurons is that this construction gives some of us (me) a feeling that we are being controlled by our bodies. But then, we are our bodies, so it is a sort of strange feeling. Examining the neuron on its own has really given me a sense of it being a separate entity from the rest of the body, though I know that is not really true.
So here are some semi-coherent thoughts on the topic. I DO believe that the nervous system is able to somehow provide for free will. I DO NOT understand exactly how. I also think that other types of systems, as in machine, artificial intelligence type replications of the nervous system can provide for free will. I'm guessing they do this in a similar way to however the nervous system does it.
I'm assuming everyone has seen them, but if you haven't, there are some really interesting (quite detailed) posters on artificial intelligence, consciousness, free will, etc. in the hallway in Park by the computer science offices. Worth taking a look at, definitely.
Name: Jen
Username: jhansen@brynmawr.edu
Subject: emotions?
Date: 2003-03-24 21:20:19
Message Id: 5153
Comments:
Ok, i am having issues making the connection of how nuerons and synapse areas can explain different emotions. I can understand how an individual with nuerons that fire rapidly might be prone to exhibit a personality with hyperactive qualities. However, i don't see how our model explains emotions such as happiness or sadness in an individual. I feel as though emotions that an individual exhibits are univerisal, such as a smile or a frown, yet the intensity at which they are seen vary? Would this differentation in intensity be attributed to the strength of signals?
Name: Elizabeth Damore
Username: Anonymous
Subject: Emotions
Date: 2003-03-24 21:35:41
Message Id: 5154
Comments:
I share some of Jen's confusion regarding the origin of emotions. I also have difficulty seeing how to explain happiness or sadness in terms of neurons and other biological factors, especially regarding the intensity of these emotions. Often, it seems that our state of mind is primarily dependent on outside events. It's interesting to think about how external influences change our moods, although I am uncertain of how these influences take place biologically.
Name: Neela
Username: nthirugn@brynmawr.edu
Subject:
Date: 2003-03-24 22:05:47
Message Id: 5156
Comments:
Annabella makes some great points. Before we can say that physiology does not encompass explain the "soul" and "free will," we must ask ourselves what those concepts mean. The problem seems to be that they are ill-defined and elusive to begin with. (Personally, I don't believe in "souls" because I could never get a handle on what they are supposed to be; debates still continue with only fuzzier results.) A soul, as many feel exists, could be a general label of some undefinable (by the limits of our understanding and language) product for which we created a term. It's sort of like the example of many blind people each experiencing a different part of an elephant: the tail, the trunk, the ears and the foot. Each of them may describe these features as completely different from what they are and may associate what they felt as distinct from one another. But, that does not mean they weren't all parts of the same creature which they never understand as a whole. What I'm trying to get at is that perhaps what lies behind concepts like the soul is not something greater and non-neurobiological but merely a muddled term that is a poorly fragmented representative of a greater picture which we are reaching for. Perhaps the problem isn't physiology's incapacity to explain the soul but our incapacity to grasp the physiological totality by the set indicators available to us. I think it may be too easy to just say that certain concepts do not originate from brain when the concepts themselves cannot be pinned down let alone be attributed to other explainations.
Name: Arun
Username: asingh@haverford.edu
Subject: Sensory Inputs continued...
Date: 2003-03-24 22:17:34
Message Id: 5157
Comments:
I understand the possibility of there being sensory inputs which we are unaware of and I do realize (by such examples as the sensory receptors in our derriere) that at times, we are unaware of receptors working and inputs traveling up the nervous system. But I agree with Laurel how certain inputs travel up the brain and that they simply reach a stage of neutral existence which makes us unaware of them.
What I'm wondering is that once we have built up these actions to a point of neutral existence or comfort zone, that we can actually improve these same receptors and how they respond. Take balance for example. We can actually improve our balance by using controlled destabilization. This sharpens the neuromuscular reflexes and is becoming a new form of training for professional athletes. One product, the Jumpsoles 4.0, actually claim to have "proprioception capability." So if these sports psychologists are stating that we are sharpening our neuromuscular reflexes when we work on our proprioceptors, can't we just categorize all sensory inputs that we are unaware of as reflexes? The nervous system builds these comfort zone so that it doesn't have to work on that input, allowing it to be most efficient -- sort of like having as few programs running as possible on a computer so that it continues to process stuff quickly.
Name: alexandra
Username: alippman@brynmawr.edu
Subject: proprioceptors
Date: 2003-03-24 22:40:23
Message Id: 5158
Comments:
Learning about proprioceptors suddenly made me able to imagine how the brain can control behavior more clearly. The effect which proprioceptors must have on the brain in telling it where the body is so that it can effect the movement or "motor symphony" makes the concept of "motor symphony" easier to grasp. After accepting the importance and existence of proprioceptors, I started to think more about them and there nature. Do certain parts of the body contain more proprioceptors than others? Would having more proprioceptors make that part more aware? Since people are different, do they have differing amounts of proprioceptors and would this change how conscious they are? How would this effect athletes? Would elite athletes have more proprioceptors than average people? Anyway that's a lot of questions but I thought they were interesting.
Name: Luz
Username: lmartine@brynmawr.edu
Subject:
Date: 2003-03-24 23:40:11
Message Id: 5159
Comments:
Some of the comments about emotions made me think about what goes on inside the brain. If neurons pass along information and our output affects our input, what about how we interpret the information? Is this where emotion comes in? Most of the time the person next to you is experiencing the same situation in a totally different way, but they are made of the same neurons. I'm feeling comfortable with neurons, but I feel as if our conversations about them make them sound too simple to explain all behavior.
Name: Christine Kaminski
Username: ckaminsk@brynmawr.edu
Subject:
Date: 2003-03-25 00:03:05
Message Id: 5160
Comments:
Central Pattern Generation is really quite an interesting topic for me. I think about many activities in everyone's daily lives and come up with examples like bike riding, playing tennis, driving a car-many things that are acquired skills, or learned central pattern generations. It makes me wonder: Are there any activities that are fully learned central pattern generations? Or do they stem a great deal from genetics? Experience plays a large part into having learned central pattern generation, however, can it really be the only factor taking away any possibility of it being a programmed response? These questions fill my mind right now. I am more inclined, however, to deduce that central pattern generation has to do with both genetics and learned experience and not solely one or the other.
Name: Michelle Coleman
Username: mcoleman@haverford.edu
Subject: Proprioceptors
Date: 2003-03-25 00:08:41
Message Id: 5161
Comments:
The idea of proprioceptors as helpful modifiers of the CNS is an interesting concept. In addition, I was equally amazed at the seemingly unresponsive nature of these receptors when stimulated, but the severe consequence of motor function ability when they are completely abolished. I wonder where this system evolved from, is it distinctive of just human anatomy or do lower class animals and/or insects have similar receptor systems, and how Christopher Reeves proprioception functions now that he is a paraplegic.
Name: maria
Username: mcruz@brynmawr.edu
Subject: the heart
Date: 2003-03-25 00:57:55
Message Id: 5162
Comments:
how would proponents of the theory that brain=behavior explain the fact that the heart is not dependent on information(pattern generation) from the brain in order to function and can continue to beat even after an organism is brain dead?
Name: Kathleen Flannery
Username: kflanner@brynmawr.edu
Subject: ...
Date: 2003-03-25 01:00:08
Message Id: 5163
Comments:
Ok, I'm with Geoff on proprioceptors. The idea that the mouse experiment relies on memory, not about some mystical sense of body in time and space, was running through my head too. This is what I think I know about proprioceptors:
They control muscles and are "sensitive" to the position and movement of the body. ("Sensitive"? Whatever that means.) And they detect the movement of a muscle and send messages to the spinal cord. There are two main types called Muscle spindles and Golgi tendon organs. What these do is another story. I haven't the faintest.
Name: e.c. fulchiero
Username: zegrete@aol.com
Subject: Affirmation
Date: 2003-03-25 01:51:09
Message Id: 5164
Comments:
As a scientifically-minded person with tendencies to overanalyze and question concepts proffered as absolute by even the most notable experts, I have found it necessary to seek documentation and illustration, which will remove my unfounded doubts regarding proprioception. Although it is neither a theoretical nor philosophical concept, in order to solidify my comprehension of that physiological reality, I have sought out tangible demonstrations of proprioceptive activity. The process I followed in my personal investigation began with a review of what I have been explicitly told to be true in class and by valid sources of biological information. It has been scientifically concluded that muscles are controlled by proprioceptors, which are receptors sensitive to the position and movement of the body. These proprioceptors detect the stretch and tension of a muscle and send messages to the spinal cord to enable it to adjust its signals to the muscles. There are two main types of proprioceptors. One type is muscle spindle stretch receptors lying parallel to the muscle. When a muscle spindle is stretched, it sends a message to a motor neuron in the spinal cord, which in turn relays a message to the muscle signalling it to contract. The human knee-jerk reflex exemplifies muscle spindle proprioception. Golgi tendon organ proprioceptors are located in the tendons at either end of a muscle and act as brakes against excessive contractions by inhibition of spinal cord motor neurons. Simplification and restatement of these concepts in familiar terms has allowed me to grasp what initially seemed to be a very nebulous concept.
During my internet exploration, I discovered a very accessible article addressing a medical investigation into the relationship between afferent innervation, muscle spindles, and proprioceptive performances as illustrated by joint position sensation and stability. This article from the Australasian Journal of Podiatric Medicine has certainly elevated my understanding of physiological awareness and neurofunctionality, and alleviated my initial tendency to question a confirmed biological mechanism. The article can be found at
http://www.apodc.com.au/AJPM/Contents/Full%20text/Vol34/Vol34%203%2086-92.pdf.
I hope that anyone else struggling with similar questions and confusions find this and the myriad articles regarding the same topic in some way beneficial.
Name: Nicole
Username: nmegatul@brynmawr.edu
Subject:
Date: 2003-03-25 02:50:00
Message Id: 5165
Comments:
In response to Maria's posting: Although not "voluntary" or within one's conscious control, a heart beat is stimulated by pacemaker cells that are in a sense responsible for starting the blood pumping rhythm. I find it hard to believe that the origin of the pacemaker cells' stimulation has no relation to the brain and so would disprove the brain=behavior theory as Maria suggests. Rather, an already transmitted signal may be received and transmitted by the pacemaker cells shortly after death thus responsible for a short period of post-mortem heartbeat, even if the brain is not actively generating new signals. I am not sure if this is the cause and would have to look it up again because it has been a while since I read about it but I am not convinced that this argument disproves the brain=behavior theory. A heart beat can be traced back to the brain.
Name: Nicole
Username: nmegatul@brynmawr.edu
Subject:
Date: 2003-03-25 03:00:15
Message Id: 5166
Comments:
After reading over my post, I realized I hadn't made something clear. The pacemaker cells that spontaneously start a heartbeat are not reliant on the nervous system directly. But, other components of the resulting behavior (a heartbeat) are related to the brain. The rate set by the pacemaker cells may be altered by nerve impulses from the autonomic nervous system or by chemicals such as thyroid hormones and epinephrine, and this may mean the lack of such impulses or chemicals (whose origins are related to the brain) could alter the pacemaker cells as well. All I am trying to say that, although not directly linked/wired to the brain, the heartbeat behavior or some portion of any other physical behavior can be related to the brain in some way.
Name: enor wagner
Username: enorenor6@aol.com
Subject: input output brain behavior
Date: 2003-03-25 03:46:50
Message Id: 5167
Comments:
Since we have recently discussed sensory inputs which we are not aware of, it has made me wonder if we have brought brain=behavior to a new level. Of course there exist sensory inputs of which we are not aware that cause noticable, tangible outputs, but do there exist outputs which we are also not aware of? Or are there sensory inputs that cause no sensory outputs? For instance, when we twitch in our sleep or breath or maintain a heart beat, we are for the most part unaware of the input that causes these outputs, but can inputs occur within us, unaware, and cause no output? When one thought triggers another thought, which one is the input and which is the output? Or are they the same thing? What about a series of thoughts? Is the mental to mental link an input output link? When I think of behavior, I think of some sort of motor symphany or action, not mental events, but can brain = behavior also mean mental behavior aswell?
Name: Stephanie Habelow
Username: shabelow@brynmawr.edu
Subject: brain=behavior & multi-tasking
Date: 2003-03-25 08:13:10
Message Id: 5168
Comments:
I agree with what Amelia said in her post about how it does make sense that there are sensory inputs or outputs that we are not aware of. If brain truly does equal behavior, I think it's necessary that there must be some things that we are either unaware, less aware of, or not able to control (either because we're unaware or just incapable). For instance, what about multi-tasking? When trying to do more than one activity at a time, there's always one activity that gets less attention than the other, but you still end up being relatively successful in completing both of the acts. I was eating cereal this morning while reading the forum, and although I knew I was eating cereal, I wasn't particularly focused on the act of eating since I was concentrating more on reading the forum. I think certainly there are some mechanisms (like memory or rehearsal) that allow for this. I think this can also be applied to similar scenarios like talking on cell phone while driving a car, or reading email while talking on the phone. If we were completely aware of everything occuring both inside or brains and outside in our environment, I don't think it would be possible for us to do different activities at the same, which, depending on how you feel about multi-tasking, might make us less efficient as humans.
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