NROSCI 1030 Lecture Notes - Lecture 15: Substantia Nigra, Striatum, Nucleus Accumbens
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Although the(cid:455) are(cid:374)"t prese(cid:374)t i(cid:374) high (cid:272)o(cid:374)(cid:272)e(cid:374)tratio(cid:374), the(cid:455) pla(cid:455) a large role i(cid:374) the disorders (cid:449)e talk a(cid:271)out: dopamine (da, norepinephrine (ne, serotonin (5-ht) Dopamine and norepinephrine are catecholamines and base their structures off the catechol nucleus. Known to have discrete (different neurons for each projection), topographic (medial to medial) projections. 11,000 dopamine neurons per hemisphere in rats 10x in humans. This is a small amount of neurons however, they collateralize extensively between 500,000 to 1,000,000 terminals. Inputs to n. accumbens (gaba), ventral pallidum (gaba), and pedunculopontine tegmentum (glu: dopamine receptors: d1-d5; d1, d5 = increase camp while d2, d3, d4 = decrease. In pfc, there are d1 (increase pyramidal) and d2 receptors (decrease interneurons: working memory. In the amgydala, pairing a painful stimulus with a non-painful stimulus is due to the dopamine receptors in the amygdala (only painful) In the dark, the dopamine goes down and it can activate all ganglion cells increased sensitivity but decreased acuity: spinal cord.
