SEASONSSocial interaction, play, and voluntarily exercise has been shown to cause hypocretin activation. This has been determined as an increase in extracellular hypocretin in the brain. Some studies have also suggested that the hypocretin neurons are regulated by light. The implications of this are still unclear.
Our research has shown that the activity of the hypocretin neurons varies with seasons, suggesting that their activity might vary over the year. This also suggests that the neurons might be particularly vulnerable at certain times of the year.
Boddum et al. PlosONE 2016
CIRCADIAN REGULATIONIt is still unknown how the hypocretin neurons regulate arousal both acutely and over the 24 hours. Our research has suggested that different subpopulations of hypocretin neurons exist, and recently other studies have shown the same.
Circadian variation in hypocretin.
Justinussen et al. Neuroscience 2015