Epithalamus
[4][5] Some functions of its components include the secretion of melatonin from the pineal gland (circadian rhythms), regulation of motor pathways and emotions, and how energy is conserved in the body.This suggests that the lateral habenula has an interaction with the hippocampus that is involved in hippocampus-dependent spatial information processing.Species that possess a photoreceptive parapineal organ show asymmetry in the epithalamus at the habenula, to the left (dorsal).[8] The Circadian timekeeping is driven in cells by the cyclical activity of core clock genes and proteins such as per2/PER2.[9] Gamma-aminobutyric acid and several peptide factors, including cytokines, growth hormone-releasing hormone and prolactin, are related to sleep promotion.