Thalamus
- 1. THALAMUS DR. ANITA CHOUDHARY PROFESSOR &H.O.D R.D.G.M.C Ujjain
- 2. THALAMUS Location upper part of lateral wall of the III rd ventricle. Thalamus is a major relay station..all general & special senses (except smell) synapse in thalamus Integrating center for all inputs before relay in CCx
- 3. Thalamus 2 Thalami Egg shaped , cluster of nuclei Connected by mass of grey matter..massa intermedia Anterior end is narrow Posterior end is broadPulvinar Internal medullary lamina divides thalami into three parts- Anterior, Medial .Lateral
- 5. Thalamic Nuclei Functional Classification Non- Specific projection nuclei RAS inputs to Thalamic Nuclei Project diffusely to whole of neo cortex Eg: Midline & Intralaminar nuclei
- 6. Connections
- 8. Functions Sensory Relay Center Sensory impulse Thalamus (Thalamocortical system) Cerebral cortex
- 9. Specific Projection nuclei-Project to specific part of neocortex Medial & Lateral Geniculate bodies Relay auditory & visual information Auditory & Visual areas of CCx Posterio ventral group Relay somesthetic information Post central Gyrus (sensory cortex)
- 10. Nuclei concerned with motor control Basal Ganglia cerebellum Give in put to Ventro lateral group of nuclei Motor Cortex
- 11. Nuclei concerned with memory & emotions Mammilary bodies give inputs to Anterior group of nuclei Limbic cortex Recent memory & emotions
- 12. FUNCTIONS OF THALAMUS Center for Integration of sensory impulse Thalamus integrates and modify the sensory impulses Functional gateway of cerebral cortex
- 13. Crude center for perception of sensations Discriminative nature Ability to recognize type Location and other details is the function of cerebral cortex Affective nature Determine sensation is pleasant or unpleasant is a role of thalamus
- 14. Center for integration of Motor Functions Basal Ganglion Cerebellum Output THALAMUS Integrate Motor function Cerebral Cortex
- 15. Role in Arousal and alertness reactions ReticularActivating System Non-Specific ascending impulse THALAMUS Controls Consciousness and maintain alertness & wakefulness
- 16. Role in emotional aspect of behavior As it is a part of Limbic system (Papez circuit) Recent memory and Emotions Role in language Cortical and Sub-cortical connections Speech
- 17. Center for Reflex activity- All sensory fibers Relay Thalamus Reflex Activity
- 18. Other functions.. Role in Synchronization of EEG Integration of visceral and somatic function Center for sexual sensation
- 19. THALAMIC SYNDROME Disturbance of emotional response to sensory experience Cause : Blockage of thalamogeniculate branch of posterior cerebral artery Damage of Ventro-posterior lateral nuclei(VPL) Damage of Ventro- posterior medial nuclei (VPM)
- 20. Symptoms & Signs -(opposite side of body) A. Sensory Symptoms : ( involvement of VPM) Astereognosis due to loss of Tactile localization & discrimination Thalamic Phantom Limb Closure of eyes Loss of kinesthetic sensation Person unable to locate position of limb in air
- 21. Thalamic Over reaction : Decrease Threshold for Pain, touch and temperature- exaggerated & disagreeable sensation Amelognosia Illusion felt by patients that his limb is absent
- 22. B. Motor Symptoms- Involvement of VPL Ataxia, decrease muscle tone & weakness (damage of cerebellar afferent) Involuntary movements- chorea, intention syndrome Thalamic hand/athetoid hand- moderate flexion of hand at wrist with increase hyperextension of fingers
- 23. Korsakoffs Syndrome Refers to lesion of MEDIODORSAL NUCLEUS of thalamus Characteristic feature: Difficult to remember new information
- 24. Frontal lobectomy Connection of dorsal nuclei of thalamus with frontal lobe is surgically removed For relief of unbearable pain
- 25. THANK YOU