seaknight navigation inc. wrote in message
<89hph3$m8a$1 at medousa.forthnet.gr>...
>What is the approximate minimum time required to perceive e.g. touch, from
>the onset of the stimulus, assuming that the cerebral cortex is necessary
>for conscious perception?
That depends on 2 factors:
1. The distance of the stimulated area from the brain (i.e. transit
time is quicker from your face than from your toe).
2. The type of nerve fiber involved. Myelinated fibers transmit much
faster than unmyelinated fibers (ex. sharp, cutting pain, which is
transmitted by myelinated A-delta fibers, gets to your brain more quickly
than dull, burning pain, which is carried by unmyelinated C fibers).
To give you a quick and dirty notion of what the actual transit times
are for touch: when I was doing research on heartbeat perception, I was told
that the time for the sensation of a heartbeat to be carried to the brain
was somewhere between 40 and 80 milliseconds.
Hope that helps.
