1. Thalamus OBJECTIVES: At the end of this lecture you should understand:
Structural & Nuclei of Thalamus
Functions of Thalamus
Thalamic Syndrome

2. The thalamus is a small structure(mass of ovoid grey matter) within the brain located just above the brain stem between the cerebral cortex and the midbrain and has extensive nerve connections to both.

4. THALAMIC NUCLEI
Internal Medullary lamina divides thalamus into 3 Parts 1. Anterior 2. Medial 3. Lateral Dorsal Group of N Ventral Group of N a. Ventro Anterior b. Ventro Lateral c. Ventro post =VPL & VPM Lateral & Medial Geniculate Bodies Intralaminar Nuclei

6. Connections Thalamus is reciprocally connected with Cerebral cortex
Anterior N = Limbic System (emotions and behavior)
Dorso medial N= receives signals from Midline Nuclei & send them to Temporal cortex & Amygdala (Limbic System).

7. connections Lateral group : (Ventro Lat, Ventro Ant & Centromedian N)
Basal Ganglia (Int. G.P) & Cerebellum and send them to Prefrontal & Pre Motor cortex.
VPL & VPM receives signals from Spinal cord & 5th N & send to Primary Sensory cortex.

8. connections Intralaminar Nuclei
receives signals from spinal cord > Cortex
Medial & Lateral Geniculate Bodies receives signals from Auditory & Visual Pathways

9. Thalamus
Fibers from Internal Globus Pallidus (Basal Ganglia) to the Nuclei of thalamus are INHIBITORY (GABA)
Substantia Nigra also project to the thalamus which is also inhibitory (GABA)
Whereas Fibers from Thalamus to the Prefrontal & Premotor Cortex are EXCITATORY

10. Functions of Thalamus Gateway to the cerebral Cortex-
Big relay station for both Sensory & Motor signals from Spinal cord- Cerebellum & Basal Ganglia
Filters out insignificant signals.
Non specific Nuclei are connected with Reticular Activating System.

11. functions of thalamus
Acts as Secondary Cerebral Cortex ( for Perception of crude sensation, Pain & Tactile Stimuli)

12. Thalamic Syndrome b. Loss of sensations on Opposite side
Blockade of an Artery to thalamus >
Affects mainly Lateral & Post Parts >
Thalamic Syndrome:
Sign & Symptoms include:
a. Muscular weakness > Decreased Muscle Tone
b. Loss of sensations on Opposite side
c. Emotional disturbances