The epithalamus (: epithalami) is a posterior (dorsal) segment of the diencephalon. The epithalamus includes the habenular nuclei, the stria medullaris, the anterior and posterior paraventricular nuclei, the posterior commissure, and the pineal gland. 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.

A study has shown that the lateral habenula, in the epithalamus, produces spontaneous theta oscillatory activity that was correlated with theta oscillation in the hippocampus. The same study also found that the increase in theta waves in both lateral habenula and hippocampus was correlated with increased memory performance in rats. This suggests that the lateral habenula has an interaction with the hippocampus that is involved in hippocampus-dependent spatial information processing.

Components

The epithalamus is a tiny structure that comprises the habenular trigone, the pineal gland, and the habenular commissure. It is wired with the limbic system and basal ganglia.

Species that possess a photoreceptive parapineal organ show asymmetry in the epithalamus at the habenula, to the left (dorsal).

Clinical significance

Dysfunction of the epithalamus can be related to mood disorders such as major depression, schizophrenia, and sleeping disorders. The Circadian timekeeping is driven in cells by the cyclical activity of core clock genes and proteins such as per2/PER2. Gamma-aminobutyric acid and several peptide factors, including cytokines, growth hormone-releasing hormone and prolactin, are related to sleep promotion.

References

  • https://web.archive.org/web/20080504165606/http://isc.temple.edu/neuroanatomy/lab/atlas/pdhn/
  • NIF Search - Epithalamus via the Neuroscience Information Framework

See also