The diencephalon

The diencephalon includes: the thalamus. the hypothalamus. the subthalamus. the epithalamus. The third ventricle lies between the halves of the diencephalon.

Now deep within the brain Mid saggital section through the diencephalon

thalamus It is a large ovoid mass of grey matter that forms major part of diencephalon. It is a station for all main sensory systems. Its anterior end forms the posterior boundary of interventricular foramen. Its posterior end forms pulvinar. Its medial surface forms the lateral wall of the third ventricle.

Its lateral surface separated from lentiform nucleus by internal capsule. It is sub-divided into anterior, medial and lateral parts, in each we have a group of thalamic nuclei.

Dorsal view shows the nuclei

Function of thalamus  relaying sensation, spatial sense and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep and alertness.

Subthalamus Lies inferior to thalamus. Its structure is extremely complex. It has subthalamic nucleus which has connection with corpus striatum. Subthalamus also contains many important tracts.

Epithalamus Consists of habenular and the pineal gland. Habenular nucleus is the center for integration of olfactory , visceral and somatic pathways Pineal glands

Hypothalamus It extends from the region of optic chiasma to the mammillary bodies lies below the hypothalamic sulcus, on the lateral wall of third ventricle. There is hardly any activity in the body that is not influenced by the hypothalamus.

Hypothalamus has important regulatory functions Temperature Emotional regulation Hunger and thirst Sexual behaviour Neurosecretion Endocrine control