Neurobiology and Behavior 2000
Class Notes

Some further implications of the brain=behavior notion Brains "sort of the same" but sort of different in different people Brains "sort of the same" but sort of different in one person at different times	Interesting. Maybe individuality and "learning" make sense this way? The brain isn't something you're born with that never changes, and its different in every person? But also similar in different people and somehow similar through time in one person? Wonder how that could be?
Elaborating the nervous system as input-output box model The need for processing within the box Why do some people, some times smile for a given input, while other people, other times don't? Maybe there are boxes inside (a "feeling a sense of humor" box?) and what happens for a given input depends on what's going on in each inside box and what they say to one another?	Hmmm. I'm not sure I get this. But .... there is something about this boxes within box idea ... different boxes doing different kinds of processing? ... behavior the result of lots of different smaller processes? ... could be ... maybe it will get clearer as we go along ... I hope.
Finding input-output boxes within the big input-output box "Broken neck" may involve interruption of all connections between brain and spinal cord - two boxes? Spinal cord has inputs and outputs related to body below neck Brain has inputs and outputs related to head There must also be pathways linking the two - brain and spinal cord each both an input and an output for the other Simpler consequences of "broken neck" Inability to move leg when asked Failure to say ouch when leg pinched Both easily understandable in terms of interrupted links between brain, spinal cord Additional phenomena of "broken neck" Leg withdraws when pinched Implies significant capability of spinal cord independent of brain Christopher Reeves doesn't report pain when leg pinched Makes sense in terms of interrupted links But ALSO suggests Christopher Reeves in brain rather than in spinal cord? Christopher Reeves can't "will" leg movement Also makes sense in terms of interrupted links IF one accepts that Christopher Reeves in brain?	Hey, this is kind of interesting. Maybe there ARE smaller boxes within the big box, but I'd also like to know about Christopher Reeves, and quadriplegia. Maybe it would make a web project? Hmmmm, there's something fishy about this "where is Christopher Reeves?" business. I need to think more about this. What does he mean that some things are "easily understandable?", and other things .... Does this all really mean that "I" is a part of neurobiology? .... and maybe only a small part of the nervous system? Grobstein had better be planning to talk more about this.
Thinking of the nervous system in terms of interconnected boxes helps us make sense of the some things, raises some more new and interesting questions. We'll look more into the idea of boxes within boxes next week. If you want to begin getting a sense of what different boxes might be, have a look at Divisions of the nervous system

Feb 1:

Some "brain=behavior" issues from forum:

• Don't need to "give up" self, etc., if find that brain "big enough"
• Will have to deal with "experience of being" - "I-function
• Will have to deal with issues of individuality, creativity, choice, "free will"

Divisions of the nervous system

Brain Development

Brain Variation

Comparative Neuroanatomy (mammalian)

Invertebrate Nervous Systems

Comparative Mammalian Brain Collections

The Whole Brain Atlas

Frog Brain

Neuroscience Tutorial

Leech Neurobiology Newsletter

Global Anatomy, includes neuroscience and histology units, resources

FlyBrain

Histology-Nervous Tissue

Types of Nerve Cells

Gallery of Neurons

Feb 3:

Interconnected boxes within boxes within boxes "Its boxes all the way down" The neuron as the smallest box we'll work with Substantial similarities in the neurons in the different larger boxes No special "neocortex" or "spinal cord" neuron	You know, this isn't quite the way I heard about this stuff before. What about what all the stuff about what the bigger boxes DO? How come we skipped over that? You know, I never thought before that in some sense all the bigger boxes are made up of more or less the same smaller boxes. Wonder if that's really true? If so, how can the bigger boxes do different things?
The neuron as an input/output box Soma = cell body Dendritic processes = receiving areas, input Axonal processes = transmitting areas, output Soma small (microns), but processes (particularly axon) can be very long (up to meters)
Some implications of discovering neurons Peripheral nervous system largely axons (though with some ganglia containing cell bodies) rigrous definitions of nervous system "inputs" and "outputs" inputs = sensory neurons, receiving surface outside nervous system output = motor neurons, transmitting surface outside nervous system	Hmmmm. So that's the answer to how we're going to rigorously define inputs and outputs? Might work, but what do we mean by inputs and outputs to the neurons?
Some significant neuron numbers LOTS of neurons (greater than 10 12 in human) Almost ALL (greater than 99.9%) interneurons Both receiving and transmitting areas within nervous system "typical neuron gets input from, sends outputs to 103 other neurons Implications for behavior? Lots going on inside?	This DEFINITELY needs some thinking about. Behavior has to do with the outside world .... somehow all those interneurons must KNOW about the outside world .... hmmm, do neurons "know things"? .... you know, some times what I do seems to have relatively little to do with the outside world .... I wonder ....
Sounds like we need to understand neurons, how they talk to one another, to make sense of any bigger boxes. That's what we'll get to starting next week.

Feb 8:

Some forum thoughts:

• Culture/upbringing - consistent with box model?
  • IF brain constantly changing based on interactions with outside world
• Mostly interneurons?
  • observations
  • interpretations
• Use only part of brain?
  • observations?
  • interpretations
  • paper topic?
• Are all neurons "pretty much the same"?
  • could be - neutrons, protons, electrons differently arranged
  • but .... will see

• Mammalian, vertebrate, invertebrate nervous systems just different arrangements of neurons

• Can signals start inside boxes?

Finding the "signal" that neurons use - the action potential Evidence from motoneuron axon, muscle, light bulbs External, longitudinal, transient, constant amplitude, moving battery

You know, he's doing it AGAIN. I LEARNED about action potentials already, and there weren't any BATTERIES. Where did these BATTERIES come from? Why can't he just talk about this stuff the NORMAL way, instead of throwing in all these things that confuse me? This diffusion thing, though, that's kind of interesting. Things always in motion (no "first mover"), random motion gives direction, maybe organization? Have to think more about that.

The resting potential as a way to understand the action potential Light bulb evidence Constant, transmembrane battery Diffusion as a deep physical reality Diffusion of ions down concerntration gradients with differential permeabilities to different ions yields stable battery No significant change in concentration gradient Gradient exists because of independent process - pump Lots of different possible batteries depending on relative permeabilities to different ions Resting potential largely due to high internal potassium and high relative permeability for potassium

Some relevant web references, for Feb 8-17:

Basic Neural Processes

The Virtual Neurophysiology Lab

From Random Motion to Order: Diffusion and Some of its Implications

Feb 10:

From the resting potential to the action potential ionic concerntration gradient, specific membrane permeability - what more? several ionic concentration gradients in addition to potassium different batteries depending on relative permeabilities sodium concentrated outside; inside positive battery with high sodium permeability adjacent membrane regions one with high sodium one with high potassium permeability yields external longitudinal battery!

You know, maybe there IS something to this "battery" idea.

Feb 15:

Some forum thoughts:

• If its "all chemicals", can all behavior be "corrected" by injecting chemicals?
• The levels of organization issue - is not JUST "chemicals", is highly organized chemicals, at several successive levels of organization
  • Small frontal lobes in people with persistant "criminal" behavior? - NY Times, Tuesday, 15 Feb
• The "normal" issue - how does one decide what should be "corrected", what not?
• Brains causing changes in other brains not novel or unusual - childrearing, education, etc all longstanding ways to "change" brains, and presumably to change organization of "chemicals"

Feb 17:

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