PSL201Y1 Lecture 18: Lecture 18 - Basal Ganglia & Cerebellum
Document Summary
Basal ganglia & cerebellum: not directly involved in programming apparatus of motor system to initate a movement) to premotor centers. Basal ganglia: regulates flow of volitional" drive (internal will, 2 tiers of nuclei, collectively known as striatum" & Striatum: topographic input (specific directing) from entire cerebral cortex & thal (centromedian nucleus where spinoreticulothalamic system terminates) Pallidum: projects to premotor centers located deep within hemispheres set of neuronal nuclei postural, locomotor) Pallidum: neurons are tonically discharging (constant background activity) inhibit premotor thalamus (esp supplementary motor area in medial wall volit"nal), s. colliculus (eye head movements, gaze-steering), mesencephalic locomotory region (locomot"n) As soon as inhibit"n removed too much in order to initiate a specific movement, a specific premotor center is disinhibited excitat"n. Central pattern generators in motor centres intiate motor program coordinat"n. Looks like backwards way of intiating action but preferred: dopamine released by substantia nigra (blacken w age since dopamine breaks down) neurons project to striatum.
