Figure 1.
Depiction of the neuroimmune network hypothesis. The cortico-amygdala neural circuit supports vigilance for and responses to threatening stimuli. This circuit includes the amygdala, a limbic region which has been implicated in emotion perception, learning and responding, and the prefrontal cortex, which participates in emotion-regulatory processes by exerting inhibitory top-down control over the amygdala and other limbic regions(Callaghan & Tottenham, 2016). The cortico-basal ganglia circuit supports reward processing and involves projections from midbrain nuclei (e.g., substantia nigra) to subcortical areas within the basal ganglia (e.g., ventral striatum) and cortical target regions (e.g., orbitomedial frontal cortex). Dopamine is the neurotransmitter most directly involved in reward processing within this circuit, playing a central role in incentive motivation, reward-based learning, and motor control(Haber & Knutson, 2009). Abbreviations: HPA = hypothalamic-pituitary-adrenocortical; IL-1β = interleukin-1β; IL-6 = interleukin-6; SNS = sympathetic nervous system; TNF-α = tumor necrosis factor-alpha. Illustration by Chi-Chun Liu and Qingyang Chen. Reproduced with permission from Nusslock, R., & Miller, G. E. (2016). Early-life adversity and physical and emotional health across the lifespan: A neuroimmune network hypothesis. Biological Psychiatry, 80(1), 1–10.