The way your body reacts to the seasons is controlled by a very old and primitive part of the brain that is about the size of a walnut. It’s called the hypothalamus.
Janis Anderson, director of the Seasonal Affective Disorders Clinical Services at Brigham and Women’s Hospital, likens it to a cluttered central clearing house, not unlike a janitor’s closet.
Anderson says that in the dark corner of the closet in your brain, the hypothalamus is hard at work, keeping the “physical plant” alive—regulating body temperature, metabolism, hunger and thirst—and keeping time on your biological clock. And it knows not just what time of day it is, it knows the time of year by keeping track of light during the day.
The hypothalamus bridges the largely rational life humans live today with the more instinctual existence we led thousands of years ago when we were closer to our less evolved origins.
“Now here in Boston,” Anderson points out, “we’re getting to the shortest days of the year… we will have approximately nine hours of light, and 15 hours of darkness.”
So the hypothalamus, always making adjustments, makes some bigger adjustments: changes to your neurochemistry that can affect energy, mood, and appetite.
Read the SAD Seasonal Affective Disorder full article here: http://wgbhnews.org/post/winter-blues-post-holiday-depression-its-all-your-mind-well-your-brain