So, basically, the brain minimizes neural circuits controlling
behaviors as it becomes more efficient. I work on crustacean central
pattern generators that are anatomically defined and have limited,
but significant, capacity to adapt. No problem.
However, the process of learning or inventing controls requires
involvement of many more circuits. In the non-learning brain, there
may be a minimal level of neural activity necessary for specific
activities. Indeed, cell death and synaptic pruning, are mechanisms
that may account for those refinements. Free ranging animals need
to constantly learn and adapt, especially if we are discussing
primates which are characterized by extraordinary learning
capacities. The reality seems to be that discovery and learning
processes have an absolute need for far more neural activity. Thus
while moment to moment we use only x percent of our brain, we need
all of our brain with all of its redundancies and parallel circuits
to function as learning and adaptive animals.
Thus, we use all of our brain.
rlh
>On 16 Jul 1999 13:57:37 GMT, didier at Glue.umd.edu (Didier A. Depireux)
>wrote:
>> >Richard Hall (rhall at uvi.edu) wrote:
> >: This is getting nowhere, slowly and painfully.
> >: If one assumes that natural selection acts on phenotypes resulting in
> >: improved fitness, it seems reasonable to assume that anything not
> >: contributing to fitness would be eliminated.
> >
> >I think that part of the idea that we need only 10 % blahblahblah, is that
> >at some point you might need 100%, while you are developing and making
> >connections, but once all the circuitry is established and you just cruise
> >through life, you only need 10% of what is there.
> >
>snipped
> >
> > Didier
>>Precisely. The is much research that show that when learning a new
>task all areas of our brains become involved, even those not normally
>associated with the actions required as the brain consciously sets
>about learning the actions required. At these times the brain does
>not behave like a collection of isolated pathways, each doing their
>own thing as is normally the case, but rather as a coherent system.
>>Then as we begin to get a handle on the task the number of brain
>regions involved diminishes until only the bare necessities required
>'light up" when the task is performed. Effectively, the brain
>establishes a "template" or "habit" that can produce the same
>behaviour as if it were still going through all the hoops of being
>consciously aware, but in reality no 'conscious" input is involved.
>>These might be of interest in this regard:
>>"The neural correlates of consciousness: an analysis of cognitive
>skill learning"
>. Raichie Marcus E, Philosophical Transactions of the
>Royal Society London B, vol 353, p 1889 (1998)
>>"The basal ganglia and chunking of action
>repertoires"
>Graybiel Ann M., Neurobiology of
>Learning and Memory, vol 70, p 119 (1998)
>>"The time course of changes during motor
>sequence learning: a whole-brain fMRI study"
>Toni Ivan et al, Neurolmage, vol 8, p 50(1998)
>>>Ian
