Re: idle thoughts on AI

"Leon2" <leonhoen@xxxxxxxxxxxxxxxxxx> escreveu na mensagem
news:f1a71$45c0ab92$86dd5270$6652@xxxxxxxxxxxxxxxxxxx
rscan@xxxxxxxxxxxx schreef:
We have seen how the function of the brain is to trigger motor program
generators.

The thalamus is usually described as the gateway to the neocortex. All
sensory information (save olfactory) and all motor programs en route
to the motor cortex pass through the thalamus. The thalamic reticular
nucleus surrounds the thalamus like a blanket. All the sensory axons
coming in, and all the motor program axons going out, pass through it.
And as the pass through, they send branches to the cells in the
blanket. The thalamic reticular nucleus is in a position to monitor
all the activity of the higher brain. The cells of the thalamic
reticular nucleus have only one output however; they send inhibitory
output to the cells of the thalamus.

The thalamus is the gateway, but the thalamic reticular nucleus has
its hand on the gate, and shuts it whenever its cells are excited.
When these cells are inhibited, the gate is open.

Essentially all the branches to the cells of the thalamic reticular
nucleus make synapses on cells that are excitatory (or are on cells
that have local inhibitory effect). When a motor act has a good
outcome, the synapses on inhibitory cells are excited. When it has a
bad outcome, the excitatory synapses are excited. When the synapses
are invoked, their ability to act in the future is enhanced. A history
of the good things, and the bad things, that happen in our life are
all recorded in the synapses of the thalamic reticular nucleus.

As we continue through life, the excitatory and the inhibitory cells
of the thalamic reticular nucleus invoked. A balance is struck. If the
balance is excitatory, the current motor program is halted in the
ventral anterior-ventral lateral nucleus of the thalamus.
The neocortex continues to trigger alternative motor programs. If the
balance is inhibitory, the motor program continues to the motor
cortex, and we act.

If the balance is excitatory, we are hesitant, we are in doubt. If the
balance is inhibitive, we have decided.

Thus does a material brain exercise free will

The thalamic reticular nucleus may also halt all sensory information
on its way to the neocortex, but that is another story.

Ray


Can you recommend a book on this subject which has f.i. images?

Try this one, my favorite (but be prepared for the weight):

Fundamental Neuroscience
http://www.amazon.com/Fundamental-Neuroscience-Michael-J-Zigmond/dp/0127808701

*PB*


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