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. Author manuscript; available in PMC: 2010 Aug 31.
Published in final edited form as: Respir Physiol Neurobiol. 2009 May 27;168(1-2):133–143. doi: 10.1016/j.resp.2009.05.010

Figure 1. Distribution of 5-HT Neurons in the Brainstem.

Figure 1

Neurons synthesizing 5-HT distribute in distinct cell groups in the brainstem classically defined as B1-B9. The rostral domain, consisting of groups B4-B9 projects “rostrally” and diffusely to the cerebral cortex, thalamus (Th), hypothalamus (Hy), basal ganglia, hippocampus (Hi), and amygdala and mediates arousal, cognition, mood, motor activity, and cerebral blood flow. The caudal domain consisting of groups B1-B3 in the medulla projects “caudally” and diffusely to other brainstem sites, cerebellum, and spinal cord and influences breathing, cardiovascular control, autonomic output, motor control, and pain processing.