Figure 1

Neural and humoral pathways in immunomodulation. During immune challenge activated macrophages and other immune and nonimmune cells release cytokines that signal the brain for activation of immunomodulatory mechanisms. Central immunomodulation is achieved by the cholinergic anti-inflammatory pathway, HPA axis, and SNS (see text for details). AP, area postrema; NTS, nucleus tractus solitarius; DMN, dorsal motor nucleus of the vagus; PVN, paraventricular nucleus; RVM, rostral ventrolateral medulla; LC, locus coeruleus; SNS, sympathetic nervous system; ACTH, adrenocorticotropin hormone; GC, glucocorticoids; EN, epinephrine; NE, norepinephrine; ACh, acetylcholine; LPS, lipopolysaccharide (endotoxin).