On Sun, 14 Jul 2002 19:25:41 GMT, Scott Powell
<teraten at descil.cjb.net> wrote:
>On Sun, 14 Jul 2002 11:53:58 -0700, Laurent wrote:
>>> On Sat, 13 Jul 2002 20:05:48 GMT, Scott Powell <teraten at descil.cjb.net>
>> wrote:
>>> Why is a human mind, purportedly a massively parallel neural network,
>>> only capable of focusing on one thing (or a very finite number of
>>> things) at a time?
>>>>>> This is something that's been bothering me for quite some time.. if you
>>> know another newsgroup that might be a better place for this question,
>>> please let me know.
>>>>>> I just wanted to add a piece of my mind : it seems to me that what is
>> done subconscientiously looks like recursive actions, like walking while
>> whisseling (very well- known actions). Couldn't that mean that the brain
>> starts those actions as self-running threads and stops them when
>> something "unusual" appends (like activations of emotions) ?
>>>> I mean : those actions are so well-known that it doesn't need any
>> thinking to run.
>>>> Is there any counter-example ?
>>>> Laurent.
>>Pattern oscillators in the muscles themselves, perhaps.
>But it is interesting to note that... let me demonstrate.
>>Think about breathing. Draw in a breath. Let it out. Now don't breathe
>while you read these next couple of sentences. Try to start the pattern
>oscillating in your lungs again, without thinking. Can you do it? Go
>ahead, try..
>>I'm curious. I can't do it. I have to maintain muscle control over my
>lungs, consciously considering each intake of breath, each compression
>and expansion of my lungs. But as soon as I think of something else, my
>breathing continues, as if it had never been an unconscious behavior.
>>So what's going on?
>>(I left this post here, but I suggest we move the topic to
>bionet.neuroscience, since in content if not origin, it belongs there,
>more - agree?)
>>Scott Powell
>without thinking about something else.
Several points. First, we seem to be able to focus on one or a few
things at a time only in our consciousness. At the same time, there
are a tremendous number of other parallel tasks still running
concurrently in other neural centers. Breathing is just one example.
There are all sorts of regulatory systems going on to control bodily
function. More "behavioral" tasks (i.e, involving the somatic system)
include maintaining the body, posture and locomotion, monitoring the
environment for novel or especially sudden changes, etc.
Second, I don't believe the notion of "recursive" is being used
correctly here. Isn't a recursive task (in computer science) one
that calls itself? The example of whistling while walking or of
starting independent threads to perform separate tasks is not really
recursive in the technical sense. It is simply multitasking.
Third, pattern generators cannot really exist in the muscles,
themselves. Many invertebrate muscles do show some independent
action, as do many smooth muscles (not to mention the elaborate nerve
network in the gut). But skeletal muscle is really just a dumb
repeater, responding only to what the motor neurons say. There do
seem to be some pattern generators in the spinal cord. Of course, the
breathing centers in the brain stem do their own pattern generation.
You really don't have to "think" about inhaling and exhaling.
Another technical quibble -- you don't breathe by controlling the
lungs. The breathing muscles include the diaphragm and the rib
muscles. The lungs follow passively.
