🚀 go-pugleaf

Some comments from Leslie Kay (lmk2@garnet.berkeley.edu) and my
responses (edited heavily and posted with permission):

>In article <2s8ihf$nbo@portal.gmu.edu> you write:
>>
>>For olfactory processing, this seems to involve the norepi system. I
>>haven't addressed that here, since it's about four stages down the road:
>>1. model the connectivity of the OB and PC in greater detail than
>>   has so far been done. Freeman's models of the OB are relatively simple,
>>   and my extension has not been towards the biology. I have to remedy
>>   that.
>
>I'd be interested to know what you would add.  The drive over here 
>has been to try to simplify the model so that the topological features
>can be derived. 

I think it's too simple. The interesting differences between an
autoassociator and a coherence detector should emerge when the
connectivity required for an autoassociator is too big. I'll be
increasing the number of activation networks to around 10 (Freeman and
Yao uses one and I worked with two) and the number of glomeruli to 20.
I'll also rewire things a bit in the PC and AON and sample the
activation networks a bit more lightly, too. (An activation network
is a collection of excitatory KI networks connected by strongly
potentiated cortico-corticals. In other words, it's the network that
wins or loses when a known pattern is seen. I'd like to see the
circumstances under which you get a 'symmetry-breaking' when known
patterns are presented. Once the symmetry is broken, the next
question is whether the system can attain a globally coherent state.
coherence==synchronization of KI networks in this context.)

>Adding more detail often doesn't work, because it
>is a macroscopic model.  THe things that happen at the mass action
>level are the result of hundreds of thousands of neurons all doing
>approximately what they are supposed to do.  So, to try to put more
>pieces into the OB may make the model less physiological.  Unless,
>of course, you are speaking of adding the noradrenergic "bathing"
>that the neurons get from time to time. (BTW noradrenergic is the
>proper word for norepinephrinergic, or at least the more commonly
>used word.)

I'm still not 'mass-action' oriented enough for Dr. Freeman's
liking. There's got to be some way of getting to the mass action
level without abandoning the middle level (between neuronal models and
the 'thermodynamic' models). Huberman and Glance have done some elegant
work in this direction, but to push it suitably will take more time
than I have right now.

Thanks for the correction. That's one of the advantages of grad school.
I'm starting in the fall, but not full time yet. 8( The norepi
'bathing' that the neurons get is step 4 in my plan.
>
>>2. study the coherent states that develop. What is required to
>>   full-blown coherence? Are most such states transients?
>
>I'm not sure there ever is "full-blown" coherence.  Again, this
>is an approximate thing at the mass action level.  And Yes, I
>believe that all states in the brain are transients.  In fact,
>perhaps it is a misnomer to say "states" at all, since really 
>there are only processes.  It is we, with our awareness or
>consciousness or whatever, who say that there are states of
>perception or awareness.

States are transients--yes, but if there's enough settling time, they
can be considered as separate things in themselves. 
>
>>3. examine the process by which the components of the olfactory
>>   system communicate. Bandwidth is key. 
>
>Absolutely.  I think that it is not the bandwidth, per se, but rather
>some other process, which we measure as bandwidth.  Really it is
>a particular part of the brain doing a particular thing at a particular
>time and its relationship with the part to which it is connected, which
>we read as bandwidth.  But it seems that the same structure may exhibit
>different bands for different functions (I think the EC is doing this).

The bandwidth measure will be the key parameter that will force one or
another model to be accepted. If the bandwidth supported by the OB/PC
interface is too low, direct sampling will not be supportable. Rather
the OB will have to sample itself and report the results to the PC.
Instead of the OB's being characterized by the cells in the PC as
'seeing a semantic object' by direct measurement, the OB will recognize
it is 'seeing' something it knows and enter a coherent state that can
be recognized by the PC. There's a lot more here, and it also relates to
some nasty unsolved problems in chaos theory and evolution. Whoever
_really_ solves it will deserve a Nobel Prize. I know some very good
physicists who think they're not really up to it, and Prigogine got his
prize in this area. It's a nasty one. Having my nose pushed into it
last week resulted in four rewritten presentations.
>
>>4. And then address training. (Skinner has done work on the biology
>>   here). 

HRE Clarification: understanding how the OB is trained via that
norepi interaction. Skinner has some interesting results here.
>
>
	
Cheers,
   harry erwin