The intralaminar thalamic nuclei (ITN) are collections of neurons in the internal medullary lamina of the thalamus.

Anatomy

Structure

The ITN are generally divided in two groups as follows: Some sources also include a "central dorsal" nucleus.

Afferents

Midline intralaminar nuclei receive afferents from the brain stem, spinal cord, and cerebellum. Connections with the cerebral cortex and basal nuclei are reciprocal. Afferents from the spinothalamic tract as well as periaqueductal gray are part of a pathway involved in pain processing.

Efferents

The intralaminar nuclei project efferents to the hypothalamus, amygdala, and limbic lobe.

Function

The ITN are thought to be involved in mediating arousal, affective, autonomic responses to pain.

Clinical significance

Degeneration of this area may occur in progressive supranuclear palsy and Parkinson's disease.

Research

This area is also prominently affected in traumatic brain injuries. One postmortem study of patients with closed head injuries showed correlation of the involvement of these nuclei with the various degrees of disability.