How Changes in Length of Day Impact the Brain

Changes in the length of day affect many aspects of the brain, including sleep and metabolism. Researchers have demonstrated that light exposure alters the composition of dopamine in the SCN, a brain area involved in photoperiod-related information processing. Researchers also have found that seasonal changes in light exposure affect behavior, diet, and autonomic function. Moreover, seasonal changes can trigger depression, such as seasonal affective disorder (SAD).

To study these changes, scientists analysed fMRI data collected from 900 people as part of the Human Connectome Project. They found that there was a significant decrease in the global signal fluctuations in the brain as the day progressed. The study also found that these fluctuations were predicted by changes in sleepiness and alertness.

Changes in the length of day also alter the brain’s internal clock, which controls the body’s temperature, metabolism, and hormone release. This information is communicated to the SCN, which in turn controls many of the body’s circadian rhythms. The SCN receives information from special cells in the retina, which detect changes in the light and day length.

Changes in day length can cause jet lag, which is the body’s reaction to being shifted from one time zone to another. Luckily, regular exposure to sunlight can help the body adjust. It also triggers the production of vitamin D, which helps prevent various diseases. In addition, it helps people sleep better.