BRS

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BRS Neuroanatomy

■ receives input from the locus ceruleus, raphe nuclei, substantia nigra, amygdala, and orbitofrontal and temporal cortices. ■ degenerates in Alzheimer disease . 3. Striatum ■ contains ACh in its local circuit neurons. ■ has cholinergic neurons that degenerate in Huntington disease and Alzheimer disease . 4. Neocortex ■ contains ACh in its local circuit neurons.

IV. NOREPINEPHRINE (NORADRENALINE)

A. Characteristics

■ a catecholamine. ■ the transmitter of the postganglionic sympathetic neurons.

■ may play a role in the genesis and maintenance of mood . The catecholamine hypothesis of affective disorders states that reduced norepinephrine activity is related to depression and that increased norepinephrine activity is related to mania .

B. Noradrenergic pathways (Figure 21.4) 1. Locus ceruleus

■ contains the largest concentration of noradrenergic neurons in the CNS. ■ located in the pons and midbrain. ■ projects to all parts of the CNS. ■ receives input from the cortex, limbic system, reticular formation, raphe nuclei, cerebel lum, and spinal cord.

Norepinephrine

Medial forebrain bundle

Thalamus

x

e

r t

c o

e o

N

Fornix

Septal nuclei

Cerebellar cortex

Hypothalamus

Amygdala

Hippocampal formation

Locus ceruleus

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FIGURE 21.4. Distribution of norepinephrine-containing neurons and their projections. The locus ceruleus, located in the pons and midbrain, is the chief source of noradrenergic fibers. The locus ceruleus projects to all parts of the central nervous system.