photo from Kemali and Braitenberg, Atlas of the Frog Brain, Springer-Verlag, 1969

Caudal to rostral sequence of "boxes" of "central nervous system" originates in neural tube development, is commmon to all vertebrates (will defer to later discussion of invertebrates, variations among vertebrates)

Each box in turn (somewhat arbitrarily) subdividable into smaller boxes (with some differences among vertebrates, to return to)

And those ... yes, "its boxes all the way down"

• dorsal medulla, cerebellum
• ventral medulla
• forebrain
• spinal cord

4 February

From Forum we don't really know how to define the "boxes" that make up the nervous system. Additionally, you have to look at the question of whether the nervous system has borders and the implications that this has for the brain=behavior idea. .... Amy Cunningham ... (today) How does the brain understand what exactly these inputs are? How does the brain and nervous system know exactly what to do? Wouldn't there have to be other outside behaviors and responses coming in? .... Rebecca Roth ... (today) From our class discussion,I was feeling the model about boxes within boxes within boxes. It kind of reminded me of when I would ask my parents a question whne I was younger. They would answer it but then it would cause me to question the answer and so on. .... Ricky Tripp ... (today and tomorrow and tomorrow and ...) Perhaps, although the brain tissues at a high magnification do look similar to each other, it is the way the brain tissue interacts with each other in general that causes the differentiation of species' behavior. For example, if you had two buckets of Lego with the same exact pieces in each bucket, you could find more than one way to use them. You could make a ship, or a plane; or maybe even a building or a house. But even though these structures were made from the exact same pieces, they ARE different structures. Perhaps this is why although the brain tissues are similar at a high magnification, the species still behave differently from each other. .... Balpreeet Bhogal ... (soon) If the presence of a neocortex suggests more complex thought process and more emotional attachments, then differences in brain structure influencing differences in behavior supports that brain = behavior. .... Shannon Lee ... (not too long) at what point in this process do living creatures (no matter how sophisticated) make decisions? What happens in the tiniest box that allows for the output not to need any input? How can it generate input from within? .... Beverly Weiss ... (not too long) It might then be interpreted that the degree of processing and the sophistication of the corresponding output is what is measured to determine the highest level of function. Yet, what accounts for emotion? How much does instinct or genetic disposition contribute to our behavior? .... Kelli Deering ... (in a bit) Back to the animals. if we have these kinds of boxes in our brains which incorporate thinking, then do animals think too? .... C. Barnes ... (in a bit) maybe there is an outside blueprint that accounts for the building parts AND for the various differences between you and me...or us and them. .... Biz Martin ... (in a bit) "Boxes all the way down": using the smallest box, the neuron, to create structures of increasing complexity and inifinite variety offers a pleasantly [and deceptively?] simple solution to the brain = behavior question, or at least the subquestion: if the brain = behavior, how do we account for the infinite variety of behavior? By an infinite variety of brains. ... The boxes all the way down model, however, does not offer [to me] as satisfying an explanation for the Harvard Rule of Animal Behavior. We can account for any living organism's unpredictable behavior by attributing that apparent unpredictability to our ignorance. If we knew enough about the organism's brain, and could control all external input, perhaps the behavior would be entirely predictable. Neuroanatomy is destiny? ... Hilary Hochman ... (yes, we'll get there)

Invertebrate nervous systems also have neurons, but differently arranged - makes sense?

Neuron as common, smallest box and as input/output element, connected to other boxes

• Cells, like other cells, but specialized to receive/process transmit "information" (as opposed to matter or energy)
• Size scale - tens of microns (10^-6) meters)
• Larger boxes must differ in how smallest interconnected
• Relevance of numbers? enough to "account for all the uniqueness that exists among people"? ... 10¹²exp10¹² possible nervous systems?
• Need to know how neurons work - to return to

Can use to show that larger boxes interconnected, in relatively specific ways (anatomical specificity) and to rigorously specify "input" and "outputs" of largest box ... nervous system itself

• grey matter (soma, dendrites, pre-synaptic terminals, neuropil) vs white matter (bundles of axons, tracts)
• central vs peripheral nervous system (some ganglia, but largely axon bundles
• output elements of nervous system (motoneurons, plus) = neurons with axon terminating outside nervous system
• input elements of nervous system (sensory neurons, plus) = neurons with receiving surface (dendrites) outside of nervous system
• everything else = interneurons
• Relevance of numbers, proportions?

7-9 February

So ... at least parts of our box within box model real ...

The boxes inside boxes (with "autonomy") model plus Additions: Inside boxes THEMSELVES have interconnected inside boxes Organization critical Internal interconnections = tracts, axonal bundles "Action" regions = neuropil (somas, dendrites, synapses) Inputs = axons of sensory neurons (plus) Outputs = axons of motor neurons (plus), can be very long And some questions (in addition to those in figure): What is neocortex for? How can model become less wrong?

Outputs - topographic organization - anatomical specificity

• Motoneurons located at levels of neuraxis related to location of muscles controlled
  • spinal AND cranial motor nuclei/nerves
• Each motoneuron activates only one muscle
• Implications:
  • "action" is not one output but pattern of activity across lots of them - "motor symphony"
  • source of lots of additional variation in behavior
  • lots of outputs/nervous system involved in any "action", is "distributed" characteristic
  • need to understand how patterns of activity created, parts coordinated

• Sensory neurons terminate at levels of neuraxis related to location of receptors
  • spinal AND cranial ganglia/nerves/terminal zones
• Implications
  • "sensation"/"perception" not one input but pattern of activity across lots of them (across modalities and, as will be seen, in one modality - another "distributed" characteristic
  • need to understand how inputs combined

For additional information: peripheral nervous system overview Sympathetic/parasymaphetic systems Enteric nervous system cranial nerves/sensory ganglia/motor nuclei spinal nerves/sensory ganglia/motor nuclei

Usefulness of the interconnected box model and ... another box?

• Capabilities of spinal cord
• Quadriplegia - relevance of topographic organization
  • Christopher Reeves and ... , from NIH
• The "I-function"

Observations "surprising", but have to be accepted - Issue is "how to make sense of them"

Two kinds of behavior ("reflex" versus something-else) intuition probably not useful

• Spinal cord capable of very sophisticated activity
• Brain capable of quite unsophisticated activity
• Distinction between "reflex" and other things?

• "foot withdraws when irritated" - spinal cord capable of sophisticated activity on own
  • is ok ... given topography and "physical contiguity principle ("PCP")

• "person doesn't say ouch when foot irritated" - behavior frequently depends on linking paths within nervous system
  • is ok ... given topography and "physical contiguity principle ("PCP")

• "person doesn't move foot when hearing (or reading) request to do so" - behavior frequently depends on linking paths within nervous system
  • is ok ... given topography and "physical contiguity principle ("PCP")

• "person says foot irritation not felt/experienced" - behavior frequently depends on linking paths within nervous system
  • is ok ... given topography and "physical contiguity principle ("PCP") AND ..
  • "behavior" can occur without it being experienced by the behaving organism AND ...
  • neuronal circuitry adequate to support "feeling/experiencing" (I-function) is in the brain (spinal cord not needed for this function)

• Where is Christopher Reeves? Is he paralyzed? Does he feel pain? - has to do with "mind", "self", "soul", "personality", "consciousness" ?
  • words requiring redefinition in light of new experiences/observations?

Ascending somatosensory pathways

12 February

First web paper due 26 February

The Christopher Reeves discussion ...

• The observations?
• Surprising? ... getting less wrong?
• How to "make sense", think/talk about observations ...
  • "reflex" vs ... ?
  • "intellgience" vs ... ?
  • body vs mind?
  • mind vs brain (nervous system)?
  • self vs brain, body?
  • the "box model" of the nervous system
    • brain and spinal cord different interconnected boxes of nervous system, each with distinctive inputs/outputs/capabilities
    • its all neurons
    • behavior is coordinated activity of different parts of nervous system
    • "internal experience" is associated with rostral part of nervous system, is distinct component of behavior
    • one input-output box is "I-function"
    • I-function functions based on inputs to it - if inputs (outputs) interrupted it has more limited function
    • I-function limited in non-damaged nervous systems as well ... restricted inputs/output capabilities?

Action potential
Resting potential
Receptor/generator potential
Synaptic potential

Action potential - longitudinal battery which appears/disappears successively at successive points along an axon ("travels" at finite speed), "all or nothing" transient (millisecond range) event

• Helps to account for "thinking takes time"
• Raises interesting timing issues for brain=behavior
• Is the common currency of "information" in nervous system, of all organisms
• Is way to "see" otherwise unobservable
• Need to understand it - doing so will help make sense of other potentials, provide insights into how ns COULD be behavior

To understand action potential, need first to understand resting potential - transverse battery, continuously present, with potential for continuous variation

• Diffusion
• Concentration gradients, ion pumping
• Diffusion of charged particles, selective permeability
• Stable transverse battery, with potential for variation

From Forum Lightening and thunder, network specificity, how gets made?, how changes?, clones?

Have resting potential (transverse battery) and core of explanation of action potential: adjacent membrane regions with different transverse batteries (because of different selective permeabilities) - Issue is how to get it to MOVE, with finite velocity?

Propagation

• passive current flow
• voltage/time dependent permeability change

Channel gating

Threshhold - non-linearitie s

And the big question ... can signals start in the middle of the box?

Have action potential, resting potential, spontaneous activity, based on ...

• ionic gradients
• selective permeabilities
• voltage/time dependent permeabilities
• passive current flow

Input (sensory) signals - an example

• Neuronal receiving surface outside nervous system
• Sensory transduction - specific channels varying permeability in response to external events
• Receptor potential - continuously variable in space/time (like passive current flow
• Transformed into action potentials
• Coding in pattern of action potentials
• Significance for behavior?
  • Restricted sample of "reality"
  • All representations of "reality" in same form, in same signals as those created in nervous system itself

Two important ideas from last week:

• Action potentials CAN start in middle of nervous system
  • New questions?
• Action potentials can be caused in nervous sytem ONLY if there are specialized neurons with permeability changes in response to particular external events
  • New questions?

• action potential vanishes at synapse
• intermediate chemical step: neurotransmitter release
• permeability change leads to synaptic potential, also continuously variable in space/time
• summation - neuron as integrator rather than relay
• inhibitory synaptic potentials, algebraic summation
• significance for behavior?
  • neurons as individual "computers"
  • "thinking backwards" - chicken with head cut off
  • "pharmacological" as well as "anatomical" specificity

• Lots of neurotransmitters
• anatomical - e.g. presynaptic inhibition
• multiple steps in synaptic transmission - e.g. neurotransmitter inaction/reuptake
• use-dependence
  • nervous system as continually evolving
• additional indirect effects of receptor activation - e.g. neuromodulation
  • signalling linked to cellular metabolism
  • nervous system as continually evolving

• hormones, other materials
• "chemicals" can be an input/ouput, modulates "state" of network
• pharmacological as well as anatomical specificity

Have done neurons, their properties. For more/different (quick sample):

• Hyperbrain, interactive vertebrate neuroanatomy summary/review, from University of Utah
• Membrane Potential and Action Potential, lecture notes from University of Arizona
• Neural Computing, includes synaptic integration, lecture notes
• Comparative Neurophysiology, includes action potentials, passive current spread, synaptic potentials, lecture notes from University of Illinois, Champaign-Urbana
• Psychopharmacology, The Fourth Generation of Progress, On-Line Edition, up to date articles on a variety of topics in cellular, subcellular neuroscience, with extensive treatment of neurotransmitters
• Vision, Hearing, and Smell: The Best Known Sense, from HHMI's Seeing, Hearing, and Smelling the World
• Senses and Sensitivity: Neuronal Alliances for Sight and Sounds, webcast lectures from HHMI
• Peripheral nervous system and receptors, lecture notes
• Sensory Receptors, lecture notes from Concordia
• Sensing the Environment, lecture notes from Sonoma State University
• The Infrared, from NASA's "The Electromagnetic Spectrum"
• ExplorTour - Looking at the World in a Different Light

Basic idea: neurons substantially similar, integrate currents due to permeability changes, send signals (action potentials, currents, chemicals) on to other neurons ... Is that ENOUGH? --------> Forum

5 March

Personally, I believe that there has to be something more that accounts for behavior. What we have discussed seems complicated enough, but it's only half way through the semester-there has to be something more! We haven't really discussed the idea of experiences and thought yet. Perhaps there is something more than what we have discussed that contributes to the that. ,,, Balpreet I think we also need to talk more about the effecr of the environment and the information that we receive through our senses and how that affects behavior. ... Amy I want to know how the brain stores information. How do these neurons work together so that information is learned? What differences lie within individuals that allow a greater or lesser capacity for knowledge?? When I get a random thought, is it the result of a spontaneous action potential, or is it a pattern of neurons working together? I really want to understand how the neuron correlates with behavior. Because we can not presume that there is anything else there but cells, it must be the patterns of these cells that account for the differences in brain and behavior amongst different species and different individuals. ... Aly There has to be something other than just neurons and the connections that equal behavior. How can the brain create or equal behavior when we can will ourselves to think and act? Neurons correlate our thinking. It does not mean that the neurons created the thought, or the behavior. Think about biting into a sour lemon. Mm, not a pleasant thought, unless you actually like the pure taste. Even if you do like it, your mind creates the thought that gives one a positive or negative feeling. First we think, then we feel. It just happens that the neurons and chemicals go along with it. On the other hand, what about chemical imbalances? ... Cass We talked about how neurons can start an action potential in the middle of a neuron, which is helpful. This provides a reason for how people can simply think of something without having some sort of stimuli. A neuron in the brain (most likely in the cerebrum)can create a cascade of action potentials which will be expressed as an idea. I'm not sure how this can be done. One must draw upon a very large number of neurons in order to even remember where I put my keys this morning. Not only do I have to think about my actions from the morning, but I have to express everything in terms of a language that I can understand -- the narrator inside our heads. This makes me very curious about language. ... Michelle Neurons all the way down [or for that matter, changes in membrane permeability all the way across] is as dissatisfying as turtles all the way down. On what is that first turtle standing anyway? What causes the first neuron to fire -- or are we positing infinity inside each nervous system? ... What does thinking look like -- is it a physical act? And how do my thoughts cause membrane permeabilities to change and action potentials to travel, when I can not will this to happen? I wrote my last paper thinking that all the fuss about the mind-body problem was just an outdated philosophers' full employment act, but now the [relatively] simple act of trying to post this week's essay, after the class discussions about neurons and action potential, makes it seem more troubling than before. ... Hilary it is difficult to see how we can understand behavior and memory when all we are allowed to work with are neurons. I recognize the argument that a complex system can result from a seemingly simplistic basis, but I still have trouble understanding exactly how this happens in the human brain. ... Gavin I think that we need to discuss the role of experience in the brain = behavior argument more, but I think that there definitely could be a way to incorporate it into our theory without the model completely breaking down. ... Mary What happened to experience, soul and emotions? I think that they play a role in shaping behavior and do not necessarily result from behavior. ... Claire It’s one thing to know that signals travel along a neuron through current flow caused by specific physical events, and quite another to accept that these signals add up to the whole consciousness of a person. Rather like we learn about atoms in grade school, and then must come to grips with the fact that only atoms make up a mountain, it takes a great deal of getting used to. It helps if one can look at some rocks: some stepping stones from the tiniest bit to the whole. ... Sarah

Have general ideas of units, rules of construction ... let's start building, see what we can get to connect the two levels?

Begin (non-traditionally) with output - "action"

Action = "motor symphony"

Accounting for motor symphony Use reafferent loop? Play from internal score? Preliminary human evidence? "central pattern generation"

Looking more closely at the "central pattern generation" hypothesis

• Earthworm locomotion
  • coordinated shortening, lengthening
  • nervous system

• includes
  • joint receptors
  • Golgi tendon organs
  • Muscle spindles - stretch "reflex"
• raises interesting issues about ns/behavior, I-function
  • How many "senses"? Why traditionally 5?
• General issues to be returned to - stretch reflex relevant in re earthworm locomotion (among other things)

• Reafferent patterning
• Central pattern generation?
• NS has "five ways to do same thing", proving A does not disprove B

7 March

Looking for some "rocks" - between neurons and behavior

Action (observable) = motor symphony (spatio-temporal pattern of motoneuron action potentials)

• Unobservable "actions"?

Humans, earthworms ... reafferent loops, central pattern generation?

Crayfish - swimmeret (female, male) beat

• nervous system
• central pattern generation?
  • common in lots of organisms, including humans
  • may be genetic, or result of experience, usually both
• location?

Motor sympony lacks a conductor - coordinated performance of independent players (cf. Boids) - efference copy = corollary discharge

19 March

Have "rocks" - Central Pattern Generator - and connections among them (corollary discharge = efference copy)

CPG from genome/experience/combination - is interconnected neurons

• Lobster stomatogastric ganglion
• Neuromodulators

Look at some more uses/implications of corollary discharge:

• role in "perception"
• role in body sense
• comparison of expectation/input
• role in behavioral choice - Pleurobranchea

21 March

Let's now reinstate reafferent loop, see what new things that gets us

Stretch "reflex"

• Knee jerk
• Muscle spindle and stretch reflexes - alternate

• input causes output; output causes input - no "simple" cause/effect
• negative feedback - stabilizing, "purpose"?
• thermostat - variable setpoint
• temperature regulation
• weight control
• others?

26 March

I began to think about syndromes in which an individual experiences the chronic and persistent sensation of pain while no physical damage is present at the site of pain. Why are these pain receptors being activated? Furthermore, is there a signal that the brain erroneously interprets as real pain? ... Kelli I am fascinated by the concept of phantom pain ... If the limb is absent, then the pain receptors from the limb are absent, so the sensation must come from the brain and not the limb. .... Beverly People whose vision has been impaired by cataracts or by the loss of a portion of the visual processing system in the brain sometimes report highly detailed visual experiences, similar to phantom limbs. Also, people who lose their hearing commonly report noises in their heads. Do these phantom phenomenon occur when the brain loses its normal input from a sensory system? ... Rebecca How is it that one can still feel where the position of their limb is if they don't have one? This is also true for those who weren't even born with one. This leads me to believe that we are all born with a few common "experiences" already in our brains ... So is this due to genetics? ... Asra The disagreement causes motion sickness. But why is it that only certain people are prone to motion sickness, while others are not phased by it? ... Kathryn I found the topic about central pattern generators very interesting. As i was listening to the lecture during class, i realized how "generalized" we made the concept seem. It seems as if every person's motor activity would be the same, given similar motor coordinations of the motor neurons. Yet, what accounts for the differences in ability? ... Sook I seem to recall that in an earlier class we discussed the notion of the tremendous variability that can be found in human brains. How then, can we account for the sometimes astounding similarities we see in the thought patterns of different people? How would studies on cloned human beings affect our current understandings? When the "parts" are the same, what does this really mean in practical terms? ... Gavin I am fascinated by the concept of phantom pain. It is especially interesting when considering the fact that anyone who has lost a limb obviously knows, consciously, that they no longer have that particular appendage. They are aware of it ... there is no way for us to consciously tell our brains that we are not feeling pain, that there is no limb there, and that the unpleasant sensations should cease .... Yasmin I think what fascinates me the most is the fact that I never really thought of choices to be so detailed, in that it relates to signals, such minute things compared to the human body as a whole. This discussion has made me think about choices in a different aspect. A choice is not constricted to whether you're going to order chinese takeout or pizza. It goes all the way to signals and the inhibitions of signals. ... Balpreet The interesting part about corollary discharge in my opinion, is that the circuits not only make sense of expectation and perception, but they make sense of choice without bringing in the I-function ... if the central pattern generator is activated by the I-function, how can the body react before the I-function is aware of it? .... Cass I would be interested in discussing what is choice now that we have changed some experiences that we thought were choice as corollary discharge. I am intrigued by the elimination of the I-function in this concept. ,,,, Gabrielle The corollary discharge patterns and reafferent loops may explain much of what appears to be either conscious or random behavior [why is it so often so easy to confuse those two??], but it explains them by explaining them away. Are we really moving toward the position that their is neither choice nor randomness in behavior? .... Hilary ... choice can account for the behavior that we observe in an organism, but that it cannot account for the experience that we believe that the organism is having. It is that one comment that I took away with me on Thursday. I must admit seeing that comment as being applicable to much more than just the case of our nudibranch mollusk. On a continuing note I ask (and realize that this question may not have an answer)what does account for experience? And are we the only ones who can define our own experiences? .... Sujatha the example of the Pleurobranchea made me feel like we were right back where we started at the beginning of the semester, since we still can't predict what the animal will do. It makes me wonder how much we can know for certain about the workings of the nervous system, especially the "I-function" and the whole concept of experience? How do we know whether we really experience things? How do we know what other organisms are capable of experiencing? .... Amy Interesting that observations on/thinking about basics of "output side" raises issues of variability, of nature of "choice", of perception, of distinction/relation between doing and being aware of doing? ... PG "I am coming more and more to the conviction that the rudiments of every behavioral mechanism will be found far down in the evolutionary scale and also represented in primitive activities of the nervous system" ... Karl Lashley, "The Problem of Serial Order in Behavior", 1951

Many more boxes/tracts relevant to output side of nervous system
Cerebellum, basal ganglia as "loops"
Focus on motor cortex

• Somatotopy (topographic organization) - "upper motoneurons"?
• frogs don't have motor cortex - not needed for movement?
• decerebrate rigidity
  • human
  • cat
  • three-toed sloth

• inhibition
• fine motor control, exploration?
• "voluntary/involuntary movement" distinction - with/without "I-function"?

Beyond motor cortex - more

Recapitulation:

Lessons learned "from the output side":

• There ain't nothing there but neurons (ion flows, permeability changes, transmitters ...)
• Action = motor symphony = spatio-temporal pattern of activity across lots of motoneurons
• Symphonies may be based on internal scores and/or afferent/reafferent signals (usually both)
• Symphonies may reflect prior inputs and/or genetic information (usually both)
• Symphonies may be endogenously generated and/or triggered by inputs (frequently both)
• Inhibition plays an important role in determining what symphonies are played
• Symphonies frequently involve distributed performances with corrollary discharge signals creating coordination
• Outputs affect inputs, both via the outside world and via corollary discharge signals
• Corollary discharge can create elements of what appears to the external observer to be "choice"
• Feedback organizations can endow systems with what appears to the external observer to be "purpose"
• Action can occur without involvement of the "I-function" or the neocortex
• Damage to neocortex abolishes the ability to create "voluntary" movement but not the ability to generate motor symphonies nor to do so in complex and "adaptive" ways in response to sensory input

28 March Expectations of what will be learned "from the input side"?

• ?

• The "classical inputs": Seeing, hearing, smelling ... touch, taste
• Additional inputs, including proprioception, pheromone detection, and ... ?
• Extra-sensory perception?
  • Info the nervous system has without the I-function about it?
  • Information from sensory neurons neuroscientists don't know about?
  • Information that "self"/"mind" has which doesn't come through sensory neurons?
    • telepathy
    • remote viewing = clairvoyance
    • precognition
• Further evidence, in any case, for "encapsulated" I-function

Recall "labelled line" - see lightening, hear thunder because different neurons activated, send action potentials to different places

• Good first approximation but ...
  • Pain?
  • Synesthesia - more
  • Complication of "perception" ... "I-function"?
  • Stay with labelled line idea, one modality

Vision as a paradigmatic case (is it? ... is at least best studied, and shows some general principals)

• "Seeing" vs light-detection
• Critical feature is information about differences, in this case differences in light arriving from different locations

2 April

The brain has many ways of doing the same things, and some of these don't reach the "I" function. ... the "I" function is a small piece of the nervous system and perhaps we don't use it as much for everyday activities as I thought we did. .... Kate I have started to notice how much I do without consciously choosing each step of the behavior. It is very interesting .... Shannon the I-function of the brain does not come into play nearly as often as I had previously supposed. It makes changes in actions when necessary, but many of the actions themselves are performed through subconscious channels like muscle memory. .... Sarah My question about this is, if the presence of a motor cortex correlates with the capability to make voluntary movements, then does that mean the I-function is located in the motor cortex? .... Aly Do all species have an "I-Function"? Can we even show that they have an "I-Function"? ... Rebecca In a scientific context, does biofeedback prove that the I-function can indeed alter the body? Does this support mind-over-matter to a greater degree than we previously acknowledged? .... Kelli I feel like we are slowly taking away peices of the I-function that we thought were significant parts, such as choice. This bothers me a little bit. .... Gabrielle It seems to me that the idea of the I-function developed in response to a recognition that we are not in total control of our actions and behaviors at every moment in time. With the I-function defined as a separate it as a distinct entity, we can explain a range of behaviors. It seems that views about many issues in contemporary society (ethics, social responsibility, etc.) can be heavily influenced by conceptions of the I-function and human agency. .... Gavin Our recent discussions of sensory perception have raised several questions in my mind. In particular, if the only way that we know the world around is through sensory perception, then does an external reality exist outside of our brain? .... Priya I think the insight that experience is subjective has a critical but distinctly limited utility in scientific inquiry: keeping it in mind keeps us honest and accurate as we observe and analyze behavior, but keeping it always at the forefront of our minds would leave us paralyzed and unable to pursue any scientific inquiry based on [more or less] objective observations. .... Hilary

"Imaging" - essential role of non-neural structures

• pin hole aperture
• refraction, optics of eye - advanced
• creates one to one correspondence between direction in space and location on retina
• creates appearance of light going in one direction rather than all directions

• Size, stability, clarity, completeness of "picture in head"? Of picture on retina?
• Important details of retina
  • fovea
  • optic disk = nerve head
• nerve head more closely examined
• picture in head NOT picture on retina ... among other things, parts "made up"
• Additional insights into "I-function"?

Picture on retina and picture in head very different

• addition of "motor" information
• "inference" ("making up") parts of picture based on other parts of picture
• what "I-function" sees is not necessarily what's out there and it doesn't know it

• reminder of retina as three layers of neurons
• photoreceptors -> ganglion cells ... "vertical" and "horizontal" connectivity
• receptors good photocells ... ganglion cells?
• lateral inhibition network and its significance
  • more "filling in"
  • reality "more real" than apparent from input received
  • inbuilt presumptions about nature of reality
  • in different worlds?

8 April

• What we see ("picture in head") is not "reality" but a guess about what is out there.
• Its an INFORMED guess.
• Raises lots of questions ...

The issue of color, or

or

Is color an aspect of physical "reality" or "made up" by the nervous system?

Physical "reality"

• Light consists of photons, intensity ~= number of photons
• Photons come in different wavelengths
• "White" = mix of photons of different wavelengths - alternate - alternate
• rainbow colors correspond to photons of different wavelengths
• colors of objects reflect absorption/reflection

• Retina - photoreceptors
• Rods/cones and photopigments
• dark adaptation
• Purkinje shift
• Trichromatic vision
• Color mixing
  • broad band channel behavior
  • three channel behavior
  • color equivalence
• Land's color constancy ... more ... alternate

• "color" is a function of brain, not of physical reality
  • Does a tree falling in the woods make a sound if no one is there?
• Individual variation
  • Color blindness
  • I am color blind
  • Color Vision - Color Deficiency
  • "Reality" of color blindness
  • Tetrachromacy?
• sensory info, like motor output, coded across populations
• brain creates "platonic ideals" - "categories" which "work"
• allows creation of things which don't exist in physical reality - non-spectral colors
• is all done without the I-function
• there is a difference between knowing how to do something and KNOWING how to do something (being able to describe how to do something) another I-function characteristic?
  relates to The Content and Epistemology of Phenomenal Belief, by David Chalmers, and Vision in a Complete Achromat, written by a vision scientist.

11 April

Have brightness, color, need third dimension?

Binocular stereopsis resolving conflict	But ... creating ambiguity

Nervous system always has five ways to do the same thing - multiple depth cues

Ambiguity as fundamental in seeing, sensory systems generally

it appears that the brain is not always able to work out which information is true, and which is false ... Sarah What exactly does reality mean? ... How do we really make sense of what goes on out there? What about hallucinations? "Believe only half of what you see, and nothing of what you hear." What do we think about that statement? ... Rebecca What is reality? This may seem like a rather abstract question, yet, as i was thinking about this, i realized that reality may really not be REAL after all ... Sook We have all had the experience of seeing something out of the corner of our eye that when we turn and look just is not there anymore. It is just to what extreme these visual hallucinations take place that deciphers whether one is "crazy" or just slightly paranoid ... Michelle The part that I find especially intriguing is that even though we now know about our blind spot, we can't make ourselves see it. This provides even more support for the encapsulated "I" function theory. It almost seems as if our brains are trying to protect the "I" function from the complexities of the reality of the world around us ... Kathryn

Reality always an hypothesis, checked and rechecked ... ?

• Disconcerting ... but also liberating

Next problem - how does nervous system create? fill in, add color, add depth?
Where IS "picture in head"?

Multiple ganglion cell types - more - multiple samples

Retinal projections ... another ... another

• multiple targets
• midbrain
• thalamus -> striate cortex
• different, parallel functions

• Visual field deficits

• Picture in head not in striate cortex

• Color and motion dissociable
• Partial color deficits
• motion blindness
• face blindness
• Distributed "picture in head"

Blindsight and its implications

• What IS "picture in head" for?
• Self as object
• I-function in neocortex?

18 April

The story of the frog ... getting it less wrong without neocortex

• more boxes
• intrinsic variability
• role of I-function?

23 April

Now that my world has been turned upside down in class, I need to recompose myself. I don't know how everyone else feels about our class discussions lately, but I feel as if I am slowly losing faith in everything that was previously so sure in my life. I always figured everyone's realities were all the same...after all isn't what we see in our heads a representation of how the world actually is? ... Ok....so now, not only are we are at the mercy of our sensory equipment, but we are at the mercy of how our brain puts this input together? And apparently, this picture is just a representation for the I-function so that we can invision ourselves in this reality? The fact that we can "see" without having this picture in our head, puts me in a state of awe. I can not fathom how it would feel to not see a picture, but still see. I guess this is because my I-function is still functioning, and I could not experience the reality of a person like this, unless my I-function did not work. ... It is interesting to contemplate what actually exists in the world and if there will ever be a way to know what truly exists out there. At the same time, maybe reality is just a subjective thing. Maybe the only way it can be defined is through us, and because we all have different realities, there can be no "truth". ... Aly Thus, our reality is a hypothesis based on the best presumption and good guess of our brain. If each person's reality is a hypothesis, what is the effect this would have on behaviour. How many of our attitudes and perceptions are indeed result of the hypothesis of our brain. And in conflict situations, how often it is about the oppositions of these same attitudes and perceptions, while the roots of many of these problems may well be in the ability to guess of the individual brains. I am thinkin along the lines of the social sciences and what consequence this could have in terms of conflict management, for example. The realization that differences are often times just the result of brains' different ways of filling the gaps ... Kornelia I would like to respond to Aly's previous post about the notion of objective reality. Postmodern theorists make the frightening assertion that objective reality simply does not exist. According to this theory, there are no absolutes and no universals ... Roland Barthes, in his critical article "The Death of the Author" argues that intentionality is irrecoverable. He suggests that a given work of literature has no absolute meaning, and that there is no use in attempting to uncover what the author meant, because his interpretation is equally unreliable. The author is born simultaneously with the text ... According to Barthes assertions, we cannot rely on anything to understand reality. If we think of a text as a form of reality, even its creator has no ownership or understanding of its meaning. We are all simply adrift in a void of meaninglessness. I find this idea very unsettling, and even more so because it is difficult to counter such a viewpoint when one's argument can be easily deconstructed as well ... Gavin it is interesting to transpose our knowledge to conflict situations in the news currently. ... is the inability to resolve political strife at core an intersection of conflicted realities? Are there no means of reconciling these differences, leaving us with a grim, conflict ridden future? ... Jenny we see the world from the culmination of all of our experiences thus far. Because our experiences are constantly changing, our brains' frame of reference is constantly in flux as well. So no one is really stable and stagnant in his/her perception of reality because the point from which one views reality is always revising itself. ... Tua "Reality" as social construct, through negotiation of individual "realities"? Always subject to updating? Science=brain="getting it less wrong"? ... PG But what if we dream of something that we have never experienced before (eg: flying, being in space). If we do not have a collection of memories for that particular experience, where would those visions come from? ... Balpreet it seems our minds have an uncanny ability to create. It can take output and create new input. ... Joan

"Generalized control mechanisms" -> emotion -> personality

• pharmcological dependence
• semi-autonomy
• pathology

Sleep/wake

• Relevant neuronal structures ... "diffuse" system
• Electroencephalogram (EEG) and implications
• circadian control
• more evidence of internal models, mismatch - jet lag
• dreams and the I-function
  • Where IS I-function? - the desynch EEG, sleep paralysis, sleep-walking
  • What is its role in personality?
  • What is its role in creativity?

• behavioral predilections (Stress as an example)
• experienced by not (at least not inevitably) caused by I-function
• influenced by genome/experience, and I-function
• "personality" as reasonably stable "behavioral predilections"?

30 April

With what time we have left, I'd be interested in discussing creativity: it seems to me solid evidence of the infinite variability of brains and of the ultimately subjective and ever-shifting nature of perception, but how do different brains produce different creative output? ... I think discussions of forensic issues in scientific settings are somewhat akin to discussions of scientific issues in forensic settings -- like penguins dancing Swan Lake: oddly captivating but not pretty. How to bring the two fields togetherin a productive way for both disciplines and for society as a whole is a never ending struggle. Yet multidisciplinary approaches to these issues so often sacrifice rigor and depth for accessibility and breadth. How to get the legal system and the scientific community talking in some productive fashion?? ... Hilary I'm also interested in exploring the individual differences among people and what accounts for them. How is it that some of us come to act in a socially appropriate way and others are given a label such as Conduct Disorder? It seems like we have a good model here, but I think it would be interesting to explore how people deviate from that model and why they deviate. ,,, Mary Is it possible that one's perceptions and memories are merely summaries of experiences, waiting to be replaced by newer summaries? ... Sook maybe we could work throught our own understanding about how personality and creativity are accounted for my the central nervous system. Also, I have always wondered about the impact of genetics versus environment. ... Tara What I want to know is what exactly is included in the "I" function? How accountable are we for our actions? How much control do we have over how we see the world? ... Kathryn Throughout the semester, the discussion of brain and behavior has raised some serious accountability questions for me. It appears that thus far, we have been able to attribute the majority of actions and behavior to the brain. However, with the mention of the Tate trial in another post, does that hold water in most real life situations? Where the insanity defense is concerned, is that a legitimate excuse for illegal action, if in nother situations that defense would be absurd. I'm just concerned with the brain and our legal system. How far can we use the brain as an excuse? In our class, very far. But if we would translate that to the real world, our entire legal and penal system would be turned on its head. Is there a way to merge the truth (yes, you did wrong because of a malfunction in your brain) with practicality (but we still must try you as a person who broke the law)? ... Jenny How does one know when someone is mentally competent? How can one's mental state really be evaluated? What is exactly happening in the brain to cause someone to act that way? Are we ever fully aware of what we are actually doing? ... Rebecca I would like to see more exploration into learning and memory. How exactly does the brain store memories and how do we indeed "learn" knowledge? Learning disorders are very common and, like emotions and other things, can help to define how others view a person. I question how different learning capabilites affect people's perceived realities. While sitting through class, we have learned many things about brain and behavior, but we have not studied the main thing that our brains do: learn. I think that learning is the missing piece of the puzzle. ... Aly I think that a discussion on learning would be a good one. I think I know a lot more about the brain than I did at the beginning of the class. But, many times the more that I know, the more I feel like I don't know. That has definitely been my experience in this class. Each subject we have covered has made me question and want to know more. Spending some time making a summary of what we learned might help bring it to a conclusion. There are scientists that spend their whole lives studying the brain without completion, so I think that we may have to do it to. ... Gabrielle

The I-function

• distributed in neocortex? parietal lobe? frontal lobe? split brain?
• qualia, intentionality
• free will, personal choice, self-responsibility

30 April

After a semester of convincing, it seems clear to me that free will does not exist ... Miranda

Emotion and "personality"

• unconscious
• I-function

• unconscious - frog, dreams
• I-function - reflecting on/altering what has been

• innate=genome
• learning and memory
  • unconscious
  • I-function - making one's own story
  • Learning and "understanding" - trying to put it all together ...

• A Beautiful Mind
• Memento

The Brain - is wider than the Sky - For - put them side by side - The one the other will contain With ease - and You - beside- The Brain is deeper than the sea - For - hold them - Blue to Bue - The one the other will absorb - As sponges - Buckets - do The Brain is just the weight of God - For - Heft them - Pound for Pound - And they will differ - if they do - As syllable from Sound -

Trust where you are at any given time Learn Explore Dream Choose And repeat, over and over and over again ("getting it less wrong" - its what your brain, and everyone else's, is "designed" to do)