Hodological study of the anterior basolateral amygdaloid nucleus and its behavioural roles in innate and contextual fear towards a predatory threat.

The anterior basolateral nucleus of the amygdala (BLAa) has been extensively investigated in studies of Pavlovian conditioning involving physical aversive stimuli. To date, there is no specific functional study of the BLAa regarding its functional roles on responses to ethologically relevant threats. In this work, we initially revisited the afferent and efferent connections of the BLAa. Our findings largely confirm previous reports in the literature, and show that the nucleus integrates information from systems related to emotional alertness (such as the locus coeruleus, dorsal raphe and innominate substance), and is also closely related to the prefrontal cortex circuitry, including the nucleus accumbens, the dorsomedial caudoputamen, and the prelimbic and anterior cingulate cortices. It also establishes important bi-directional connections with the insular cortex and parahippocampal region. We also tested the specific role of BLAa in innate and contextual responses to predatory threat. Thus, we have seen that BLAa influences innate and contextual fear responses to predatory menace. Firstly, we suggest that the BLAa responds to the predator\'s stimulus by the emotional arousal systems, given that it receives inputs from alert related structures highly responsive to the predator threat, such as the locus coeruleus. We also suggest that through its projections to the nucleus accumbens, the BLAa may influence innate defensive responses. In addition, we suggested that the BLAa influences contextual fear responses mostly through its relationships with the prelimbic, anterior cingulate and parahippocampal cortices. (AU)