The pallidothalamic tracts (or pallidothalamic connections)
are a part of the
basal ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...
. They provide connectivity between the
internal globus pallidus
The internal globus pallidus (GPi or medial globus pallidus; in rodents its homologue is known as the entopeduncular nucleus) and the external globus pallidus (GPe) make up the globus pallidus. The GPi is one of the output nuclei of the basal gan ...
(GPi) and the
thalamus
The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all direction ...
, primarily the
ventral anterior nucleus
The ventral anterior nucleus (VA) is a nucleus of the thalamus. It acts with the anterior part of the ventral lateral nucleus to modify signals from the basal ganglia.
Inputs and outputs
The ventral anterior nucleus receives neuronal inputs from t ...
and the
ventral lateral nucleus
The ventral lateral nucleus (VL) is a nucleus in the ventral nuclear group of the thalamus.
Inputs and outputs
It receives neuronal inputs from the basal ganglia which includes the substantia nigra and the globus pallidus (via the thalamic fas ...
.
Anatomy
They are composed of the
ansa lenticularis
The ansa lenticularis (''ansa lentiformis'' in older texts) is a part of the brain, making up the superior layer of the substantia innominata. Its fibers, derived from the medullary lamina of the lentiform nucleus, pass medially to end in the thal ...
, the
lenticular fasciculus (
field H2 of Forel), and the
thalamic fasciculus (
field H1 of Forel).
* The ansa lenticularis is composed of fibers that pass from the ventral aspect of the