Connectionists: How the brain works

[Juyang Weng]

I agree with Thomas in terms of "theory must find its way into 
mainstream neuroscience, much more than it currently is".

However, a radio, or a more sophisticated system like a space shuttle, 
is a bad example for us to consider how the brain works, because it 
lures us to miss the boat.  Why?  A radio or space shuttle does not 
learn autonomously, neither does a multilayer perception in a typical 
context where it is taught in a university class.  For the same reason, 
with respect, I think that Steven Pinker's book "How the Mind Works" 
also miss the boat.  I did enjoy rich published information in his book 
and I told him so when he and I met last year.  But Pinker's book hardly 
ever discussed how the brain learns autonomously in his book.  His 
discussion about brain's plasticity is superficial, mainly an account of 
experimental facts without linking to mechanisms about how the mind 
works.  As far as I understand from my (controversial?) brain theory, 
brain plasticity is a small window for us to peek into the brain "first 
principle".

The first principle for us to understand how the brain work, as I 
allured to in my last email to this list, is:
Principle 1:  Development --- How the brain learns autonomously through 
life time.   A brain has sensory neurons (receptors) and muscle neurons 
firing all the time before birth and after birth. Any theory about the 
brain must explain how this biological machine learns autonomously. 
Still remember the "cluttered environment" I wrote earlier?   A fetus 
brain or a baby brain must deal with cluttered environment directly!

I leave others to fill other principles.  Note: How the brain works 
cannot be the first principle, since how it learns determines how it 
works.  We might fill other brain principles as we continue this discussion.

-John

On 1/26/14 11:39 PM, Thomas Trappenberg wrote:
>
> Some of our discussion seems to be about 'How the brain works'. I am 
> of course not smart enough to answer this question. So let me try 
> another system.
>
> How does a radio work? I guess it uses an antenna to sense an 
> electromagnetic wave that is then  amplified so that an electromagnet 
> can drive a membrane to produce an airwave that can be sensed by our 
> ear. Hope this captures some essential aspects.
>
> Now that you know, can you repair it when it doesn't work?
>
> I believe that there can be explanations on different levels, and I 
> think they can be useful in different circumstances. Maybe my above 
> explanation is good for generally curious people, but if you want to 
> build a super good sounding radio, you need to know much more about 
> electronics, even quantitatively. And of course, if you want to 
> explain how the electromagnetic force comes about you might need to 
> dig down into quantum theory. And to take my point into the other 
> direction, even knowing all the electronic components in a computer 
> does not tell you how a word processor works.
>
> A multilayer perception is not the brain, but it captures some 
> interesting insight into how mappings between different 
> representations can be learned from examples. Is this how the brain 
> works? It clearly does not explain everything, and I am not even sure 
> if it really captures much if at all of the brain. But if we want to 
> create smarter drugs than we have to know how ion channels and cell 
> metabolism works. And if we want to help stroke patients, we have to 
> understand how the brain can be reorganized. We need to work on 
> several levels.
>
> Terry Sejnowski told us that the new Obama initiative is like the moon 
> project. When this program was initiated we had no idea how to 
> accomplish this, but dreams (and money) can be very motivating.
>
> This is a nice point, but I don't understand what a connection plan 
> would give us. I think without knowing precisely where and how strong 
> connections are made, and how each connection would influence a 
> postsynaptic or glia etc cells, such information is useless. So why 
> not having the goal of finding a cure for epilepsy?
>
> I do strongly believe we need theory in neuroscience. Only being 
> descriptive is not enough. BTW, theoretical physics is physics. 
> Physics would not be at the level where it is without theory. And of 
> course, theory is meaningless without experiments. I think our point 
> on this list is that theory must find its way into mainstream 
> neuroscience, much more than it currently is.  I have the feeling that 
> we are digging our own grave by infighting and some narrow 'I know it 
> all' mentality. Just try to publish something which is not mainstream 
> even so it has solid experimental backing.
>
> Cheers, Thomas
>

-- 
--
Juyang (John) Weng, Professor
Department of Computer Science and Engineering
MSU Cognitive Science Program and MSU Neuroscience Program
428 S Shaw Ln Rm 3115
Michigan State University
East Lansing, MI 48824 USA
Tel: 517-353-4388
Fax: 517-432-1061
Email: weng at cse.msu.edu
URL: http://www.cse.msu.edu/~weng/
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