"Explaining animal minds as intentional, self-organizing, creative systems in prelude to understanding consciousness"
Neuphi
May 1, 2007, 4-6PM
Note-taker: J. T.
Last Updated: May 5, 2007
Q&A (Multiple questioners numbered where applicable)
Q: So I can articulate an experimental philosophy: there are many
events in the brain one can measure; and one can analyze those signals
in a variety of ways, but at the end of the day, one must be able to
account with these analyses for something the subject can do. Can you
use this theory to account for what the animal is doing on a moment by
moment basis?
A: I think that the thrust of our recording now is on multivariate
emissions, and thus have to be analyzed offline. The kind of response
we were testing were simple, and all our experiments were performed
with full knowledge of the animal's response. We can discriminate
between three different odors given the EEG images, but more than that
is too complex. The big difficulty right now is working with large
numbers of neurons.
Q: You pointed out [Claude] Shannon's recommendation not to use info
theory for brain modeling. I think you fall into the same trap when
you try to use a thermodynamic approach. You have an alternative, say
what Wolf Singer (sp?) is saying.
A: I think that computational models are a crutch that can be used to
interpret the data, but that don't actually explain what the brain is
doing. The key problem I see with the application of info theory is
that the response of the animal depends on its expectation, which in
turn depends on its knowledge base. You cannot measure knowledge with
information. You might be able to measure the information in terms of
the molecules you give to the rabbit to smell, but you cannot measure
the amount of information that finally arrives in the rabbit's neural
system. I will say that the averaging that takes place in
thermodynamics is matched by the spatial averaging that dendrites do,
so in that way the theory is a better fit than you suggest. However,
it is true that a statistical thermodynamic approach that doesn't
account for the individual properties of neurons is bound to fail.
Q1: It seems to me that your discussion of the cinematographic property
of perception should be able to explain our conceptual capacity to fuse
images.
Q2: It seems this whole perceptual framing thing has been lost, which
is too bad.
Q1: Well maybe now… Matt Wilson's group has some interesting ideas
about the usefulness of theta [frames]. There it's a sort of way to
perform temporal compression.
Q1: I noticed you mentioned that there are both excitatory and
inhibitory neurons in the same system, and so it looks like there would
need to be something else controlling them.
Q2: If we accept Freeman's position, the activity of the system doesn't
get its meaning from an external source, it is internally propagated in
the system. But this discussion of individual neurons isn't meaningful
philosophically. Their only meaning is collectively, with respect to
background activity in the entirety of the system.
A: That's right, there is an amplification of the meaning of an
individual neuron's activity to the rest of the system.
Q: As an engineer, something that is absent to me [from your
explanation] is the Turing test. The model given in the theory seems
entirely distinct from what I would normally take a person to be.
A: We're starting work on a field called intentional robotics, in fact.
Hoping to develop some robotic applications out of this.
Q: You've criticized models in cognitive science. I define models as a
parsimonious set of hypothesis that allows prediction of the unknown.
I think that applies to models of the brain as well as physics…you toss
off these remarks about models as not explaining what brains are doing.
A: I think what I was trying to do was make a distinction between a
model and a theory. What I was discussing in my history of models of
the brain was a breakdown in theory, and I believe that info theory has
had its day — we should return to an energy, or power-based theory.
Reading: http://www.neuphi.com/images/readings/AD-.Category_.errors_.pdf