The habenular commissure, is a brain

commissure A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. * The most common usage of the term refers to the brain's commissures, of which there are five. Such a commi ...

(a band of nerve fibers) situated in front of the

pineal gland The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep, sleep patterns in both circadian rhythm, circ ...

that connects the

habenular nuclei In neuroanatomy, habenula (diminutive of Latin ''habena'' meaning rein) originally denoted the stalk of the pineal gland (pineal habenula; pedunculus of pineal body), but gradually came to refer to a neighboring group of nerve cells with which th ...

on both sides of the

diencephalon The diencephalon (or interbrain) is a division of the forebrain (embryonic ''prosencephalon''). It is situated between the telencephalon and the midbrain (embryonic ''mesencephalon''). The diencephalon has also been known as the 'tweenbrain in ol ...

. The habenular commissure is part of the

habenular trigone In neuroanatomy, habenula (diminutive of Latin ''habena'' meaning rein) originally denoted the stalk of the pineal gland (pineal habenula; pedunculus of pineal body), but gradually came to refer to a neighboring group of nerve cells with which th ...

(a small depressed triangular area situated in front of the superior colliculus and on the lateral aspect of the posterior part of the

tænia thalami In the front, superior surface of the thalamus but separate from the inner, medial surface by a salient margin is the taenia thalami (Latin for "flat band" of the thalamus). The bottom epithelial lining of the third ventricle The third ventric ...

). The trigonum habenulæ also contains groups of nerve cells termed the

ganglion habenulæ A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympathet ...

. Fibers enter the trigonum habenulæ from the stalk of the

, and the habenular commissure. Most of the trigonum habenulæ's fibers are, however, directed downward and form a bundle, the

fasciculus retroflexus of Meynert ''Fasciculus vesanus'' is an extinct species of stem-group ctenophores known from the Burgess Shale of British Columbia, Canada. It is dated to and belongs to middle Cambrian strata. The species is remarkable for its two sets of long and sho ...

, which passes medial to the

red nucleus The red nucleus or nucleus ruber is a structure in the rostral midbrain involved in motor coordination. The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. ...

, and, after decussating with the corresponding fasciculus of the opposite side, ends in the

interpeduncular nucleus The interpeduncular nucleus (IPN) is an unpaired, ovoid cell group at the base of the midbrain tegmentum. It is located in the mesencephalon below the interpeduncular fossa. As the name suggests, the interpeduncular nucleus lies ''in between'' t ...

External links

NIF Search - Habenular commissure
via the

Neuroscience Information Framework The Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/ genomic resources and provides many aut ...

{{Authority control Habenula