Fig. (1).

Locus coeruleus projections to brain areas responsible for amphetamines-induced behavioural responses. Amphetamines cause a massive NE release in all the brain areas that receive NE inputs from locus coeruleus. Locus coeruleus inputs into NAc are suggested by much experimental evidence (see text). An increase in NE-mediated signals on NAc and PFC produces the typical behavioural responses induced by amphetamine derivatives. Conversely, dorsal striatum possesses only scattered NE afferents from locus coeruleus. Locus Coeruleus receives inputs from several cortical and subcortical regions. Descending fibers from cortical areas mainly derive from the dorsolateral and dorsomedial prefrontal cortex. Amigdalo-coeruleus projections releasing corticotropin-releasing hormone and dynorphin suggest the involvement of LC in the control of limbic functions. Hypocretin/orexin innervation from the posterior hypothalamus is involved in the LC regulation of sleep/arousal responses. Finally, monoaminergic innervation to LC derives from raphe nuclei, lower medullary A1 and A2 NE nuclei, and VTA. A, amigdala; A1, A2, NE nuclei; C, cerebellum; CRT, corticotropin-releasing hormone; DA, dopamine; DS, dorsal striatum; Glu, glutamate; Hcrt, hypocretin; Hyp, hypothalamus; 5-HT, serotonin; NAc, nucleus accumbens; NE, norepinephrine; LC, locus coeruleus; PFC, prefrontal cortex; RN, raphe nuclei; SN, substantia nigra; VTA, ventral tegmental area.