The thalamus is divided into anterior, medial, and lateral parts by the internal medullary lamina. The lateral part contains dorsal and ventral tiers of nuclei that relay sensory and motor information between the brainstem and cortex. The thalamus plays key roles in sensory relay, motor control, emotion/memory, and vegetative functions by transmitting information between different brain regions. Lesions of the ventral posteromedial and ventral posterolateral nuclei can cause loss of sensation on the opposite side of the body.

1. Thalamus and its connection
Presented by:
Dr. Md. Akmol Hossain
Resident(phase-A), Neurology.

2. 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

3. 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

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

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

8. Input to the Thalamus

9. Motor control and integration

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

11. Motor control
and integration

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

13. 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

15. 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.