Central, But Not Basolateral, Amygdala Is Critical for Control of Feeding by Aversive Learned Cues

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Abstract
Environmental factors contribute to the motivation to eat and can override homeostatic signals to stimulate eating in sated states, or inhibit eating in states of hunger. In particular, stress, fear, and anxiety have been linked to suppression of eating and anorexia nervosa. Here, we use a rodent model of an aversive cue-induced cessation of feeding. In this setting, food-deprived rats suppress eating when presented with a tone [conditioned stimulus (CS)] that was previously paired with footshocks [unconditioned stimulus (US)]. To begin to delineate the underlying neural circuitry we examined the two regions of the amygdala with well known roles in associative learning—the central nucleus (CEA) and the basolateral area (BLA; includes the basolateral, basomedial, and lateral nuclei). We produced selective, bilateral, neurotoxic lesions of the CEA or BLA, and then trained these rats together with sham-lesioned controls in a behavioral protocol that allowed a test for food consumption in the presence of an aversive CS. Both sham- and BLA-lesioned rats showed inhibition of eating when presented with the CS. In contrast, bilateral, neurotoxic lesions of the CEA abolished this effect. These results demonstrate that the CEA, but not BLA, is critical for control of feeding by an aversive CS. Previously we demonstrated that enhancement of eating by an appetitive CS is dependent on the integrity of BLA, but not CEA. Those findings together with the current results show a double dissociation between amygdalar subsystems that control food consumption by appetitive and aversive learned cues.