Posted by gary (209.187.112.85) on January 30, 2000 at 00:27:15:
on occasion we get into the seasonality of episodic CH, which tho not uniform OR universal,
DOES occur in such a high fraction of the CH popul. that it is often discussed in clinical descriptions -
lots of speculation of possible natural light cycles having something to do w/CH
in that focus,
CHECK THIS OUT - KINDA COOL!
(drawn & compiled from a current literature search we're doing on a wildife study)
a. we all know: most animals are very tuned to circadian (daily) rhythyms of sleep, wakefulness, energy levels, etc, humans included - mostly tied to daylight factors (there are several different daylight variables, not just length of sunlight period)
b. beavers under the ice in the winter often abandon (or lose, depending on your perspective) normal circadian behavior patterns IF the light coming thru the snow & ice is reduced below a specific (to region) intensity
c. there are a few other animals who lose the "timeclock" function at a lowlight threshold level, that varies by region and population group -
humans included,
d. the daily behavior/activity schedule in turn, changes thru the year, appropriate to the environmental changes in the animals life activities, and at the same time triggered by environmental changes
e. many of these seasonal changes (annular rhythyms, as opposed to circadian rhythyms) are not triggered by LENGTH of daylight alone,
a factor that has been demonstrated as extremely important is the INTENSITY of light at dawn & dusk, which is primarily dependant on the angle of the sunlight to the surface, which of course changes in an absolutely exact pattern thru the year, no matter what is happening to the weather, food supply etc.
if we think about it - this is probably a "no duh", once we focus on it
the length of daylight is a pretty complex determination for primitive process dynamics BUT-
INTENSITY of light is a "snapshot" computation - much much simpler set of variables to process, and little or no retention required - so it is in fact probably MUCH more important than simple length of day, simply because it is a variable more readily processed by the senses and subintellect neurological system
with me so far ??????????
OK then:
part of the physiology that affects beaver - and our - circadian rhythyms is an alteration of the amount of melatonin produced by the pineal, which then links into hypothalamic response to environmental conditions
a defect in this chain reaction can block or alter the response to external stimuli
(in the case of beaver, this "malfunction" results in behavior which ends up benefiting them in surviving the winter)
basically - strange light conditions can cause fully "automatic" physical disruptions which persist as long as the abnormal light factor is maintained
NOW -
one of the CLASSIC symptoms/associated dynamics of "classic" CH is a disruption of normal circadian rhythyms
~~~~~~~~~~~~~
Possible CH relevance?
.....remember, systems work nice & neat WHEN they're working correctly;
if a link in the chain is broken, mishaped or misdirected, then not only does the system falter,fail, or produce inappropriate results-
- it ALSO is no longer interpretable by the definitions of the normal system
..to do so is like trying to find a rational explanation for the behavior of an irrational person
as I have said before -
I wouldn't DARE suggest I had a great theory about CH based on a handful of details
(unlike some CHMB people, who seem to delight in getting all X-Factored on us at the drop of a clue - that ISN'T how anything is ever reliably determined in real life, and they do themselves or us no favor in charging down those paths - but whaddaya gonna do ?)
BUT -
we do get somewhere by working on collecting pieces of the puzzle, one at a time,
and making as sure as we can that each piece is VERY well documented and accurate BEFORE we put it on the table,
then have faith that someday - time is irrelevant here in understanding the research working model - we will have enough pieces on the table to begin to see how they PROBABLY go together - then, and only then, can we reasonably start experimenting with assembling the whole picture
in the same literature search we also turned up ANOTHER subset of info re: regional human adaptation over 1000s of years, that can result in TOTALLY DIFFERENT physiological responses to the same environmental stimuli, from one regional group to another