ken collins <kckpaulc at aol.comABCXYZ> wrote:
> why, with respect to the optimization of 'cognition', we =must= 'sleep' is
> exactly known. it's as i've discussed... unfortunately, my unemployment checks
> are mutually-exclusive with attending conferences :-)
Hi, Ken,
Yes, I know that I am privileged, having the possibility to attend most
important conferences in my field.
The =must= sleep necessity can be defined not only in terms of
(input/output)*noise/whatever, but also in more easily understandable
terms like:
- which cognitive functions do not need sleep (logical reasoning,
learned abilities: these are not impaired by sleep loss), and
- which do need sleep (decision-making, finding solutions in a new setting,
creativity: these are cumulatively impaired by sleep loss, and cannot
according to present scientifical knowledge be restored by any other
means than actually sleeping).
Many previous opinions about the cognitive impairments due to sleep loss
are based on tests that do not adequately discriminating between sleep
loss-sensitive and sleep loss-resistant capabilities (sorry for the
generalizations, Frank and others, I will try to sort this out for myself
soon). It is not even valid to say that prefrontal cortex functions are
disturbed by sleep loss; one has to be more specific than that.
What this means on a cellular/subcellular level is not clear to
anybody at present, but there are some nice hypotheses around, and data to
support them. It is nearly sure that no single chemical factor can
explain the physiological need for sleep, so we can all stop looking for
the simple answer.
Dag Stenberg
