12-14 More specifically, the basolateral complex Is comprised of the lateral, basal, and accessory basal nuclei, which

are richly Innervated by neocortlcal and subcortical uni- and poly-modal sensory regions,13-15 which then relay Information to the central nucleus of the amygdala.16 Intraamygdala connectivity is widespread.13,14 The central nucleus projects to numerous nuclei in the midbrain and brain stem to orchestrate the rapid and primary behavioral, autonomic, and endocrine responses to threat and danger.3,5,17 The central nucleus also receives Inhibitors,research,lifescience,medical visceral information from brain stem sites that include the solitary and parabrachial nuclei18 and reciprocally projects to these brain stem regions (eg, ref 19). Regions of the amygdala directly project Inhibitors,research,lifescience,medical to the nucleus accumbens, which led investigators20,21,22 to suggest an anatomical route by which motivation and motor control action are linked in the organization of

active behavior (see also refs 21-25). In click here addition to projections from the central nucleus of the amygdala to midbrain and brain stem targets important for mounting quick behavioral, autonomic, and endocrine responses to danger, the amygdala projections to the cortex and subcortical structures are also quite extensive.13,14 In rat, the sources are the lateral, basal, and accessory basal nuclei, and their projections Inhibitors,research,lifescience,medical are fairly restricted to the multisensory temporal lobe structures (perirhinal, pyriform, and entorhinal

cortices) and prefrontal cortex.26 In primate brain, the primary visual cortex also receives input from the amygdala.12 These cortical structures also contribute the heaviest cortical input to the amygdala, Inhibitors,research,lifescience,medical suggesting that many of the connections between the amygdala Inhibitors,research,lifescience,medical and cortex are reciprocal. This is particularly the case with the amygdala and prefrontal cortex, both anatomically12,26 and functionally (for review see refs 27, 28). In addition to the basolateral nucleus of the amygdala, the central nucleus of the amygdala also plays a unique role in conditioned fear.3,5 The basolateral complex of the amygdala, with its rich afférents from the thalamus and cortical regions, is neuroanatomically situated to connect information about neutral stimuli with those that produce pain or are harmful. The central nucleus can orchestrate almost behavioral responses related to fear via its direct connections to numerous midbrain and brain stem regions and circuits instantiate ing various fear-related behaviors.17,29-31 Thus, the central nucleus of the amygdala, via its projections to lower brain, orchestrates behavioral (freezing5,17), autonomic, and endocrine responses to fear, while efferents of the basal nucleus of the amygdala participate in active avoidance behaviors to fear,23,32,33 likely through basal ganglia.