Habenular nuclei

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Status

Done

Parent item

Epithalamus

Two parts to the nuclei

• Medial (MHb)

• Lateral (LHb)

Located in habenular trigone

• A triangular depression in the wall of the 3rd ventricle

Relations

• The trigone lies in relation to the dorsomedial part of the thalamus.

• It is medial to the pulvinar, separated from it by the sulcus habenulae.

• The superior colliculus lies just behind and below the trigone.

Habenular commissure

• Formed by some fibres of the stria medullaris thalami cross within the superior (or anterior) lamina of the pineal stalk to reach the contralateral habenular nuclei

• Connects the habenular nuclei of the two sides

 

Connection

Afferent

Stria medullaris thalami

• Connects to Amygdala to habenular nucleus

• A bundle of fibres

• Relations
• Lying deep to the taenia thalami
• Along the junction of the medial and superior surfaces of the thalamus

• Begins near the anterior pole of the thalamus and runs backwards to reach the habenular region.

• Afferents
• From the septal nuclei and pass through the stria medullaris thalami.

• Several neuromediators have been demonstrated in the fibres of the stria medullaris.
• Acetylcholine
• Noradrenaline
• Serotonin
• Gamma-aminobutyric acid (GABA)

• Terminology
• There are two stria medullaris in the brain
• Stria Medullaris in the epithalamus
• Stria Medullaris in the medulla

• Stria medullaris is not the same as stria terminalis (Connects amygdala with hypothalamus)

Efferent

• Fasciculus retroflexus (FR) (in purple)
• Aka:
• Habenulointerpeduncular tracts
• Meynert's fasciculus
• Passes medial to red nucleus and ends in interpeduncular ganglion/nucleus
 

Function

• Center for integration of olfactory, visceral, and somatic afferent pathways

• They may be involved in control of sleep and in temperature regulation.