Thalamus and its connection

Presented by:Dr. Md. Akmol Hossain

Resident(phase-A), Neurology.

The gray matter of thalamus is subdivided into three parts by Y-shaped internal medullary lamina 1. Anterior part-Anterior thalamic nuclei

2. Medial part-Dorsomedial nucleus 3. Lateral part

Lateral Part again divided into A. Dorsal tier of nuclei 1. Lateral dorsal nucleus 2. Lateral posterior nucleus 3. Pulvinar B. Ventral tier of nuclei 1. Ventral anterior nucleus 2. Ventral lateral nucleus 3.Ventral posterior nucleus a. Ventral posteromedial nucleus b. Ventral posterolateral nucleus

Posterior view of the brainstem showing the thalamus and the tectum of the midbrain.

Coronal section of the cerebral hemispheres showing the position and relations of the thalamus.

Input to the Thalamus

Motor control and integration

Sensory relay - Ventral posterior group all sensation from body and head, including pain

Motor control and integration

Sensory relay Ventral posterior group

all sensation from body and head, including pain

Function of thalamus:• Thalamus has four basic functional roles:

– Sensory• All sensory information (except olfaction) is relayed to the

cortex via the thalamus– Motor

• Motor system outputs from the basal ganglia and cerebellum are relayed by the thalamus

– Emotion/memory• The thalamus is part of the Papez circuit and helps control

some emotional and memory information going to limbic cortex (cingulate gyrus)

– Vegetative• The thalamus has some intrinsic nuclei associated with

alertness and arousal. Can be associated with disorders of consciousness

Lesions of Thalamus:Damage to the ventral posteromedial and ventral posterolateral nucleus will result in the loss of all forms of sensation , including light touch, tactile localization and discrimination, and muscle joint sense from the opposite side of the body.