PSYC 108 Lecture Notes - Lecture 12: Putamen, Prefrontal Cortex, Cerebellum
Document Summary
Indirect pathway = stopping movements: huntington"s disease, massive loss of striatum, symptoms: choriec - involuntary movements (writhing) Indirect pathway neurons are depleted - can"t stop movements: parkinson"s, flip side to huntington"s, hard to initiate movement, caused by loss of dopamine neurons of substntia niagra (snc) Loss of activity to striatum: weakened direct pathway, motor loop, normal movement generation. Starts with a cortical motor plan: moves to basal ganglia, disorders. Striatum -> gpi -> thalamus: tic generation (turrets) Inappropriate limbic activation of striatum = inappropriate, obsessive thoughts/motivations. Inappropriate associative activation of striatum = hallucinations: dopamine pathway, nigrostriatal pathway. Substantia nigra is involved in reward learning: experiment: Dopamine neurons of sn fire after reward: after sig(cid:374)al is co(cid:374)ditio(cid:374)ed i(cid:374) (cid:373)o(cid:374)keys later sig(cid:374)al is way earlier than reward, sn fire during signal rather than reward. Shows these neurons are involved in some type of learning. Sn and cortex are both acting on striatum neurons.
