Characterization of Behaviors During Food Consumption Under Novelty and Threat Learning in Male and Female Rats (full statistical output)

Fear and anxiety are related but distinct responses to imminent versus uncertain threat. Suppression of eating under novelty is an evolutionarily conserved, cross-species model of anxiety, and it is beneficial to determine if this behavior can predict individual differences in fear learning and memory. The present study examined behaviors during novelty-induced suppression of eating and fear learning and memory in male and female rats, and determined which behaviors correlate across the two paradigms. Experiment 1 tested consumption of novel versus familiar foods in a novel or familiar context across two sessions. During the first session, subjects in the novel context consumed less familiar food than those in the familiar context, demonstrating novelty-induced hypophagia. Novel food consumption did not differ by context. During the second session, all subjects increased consumption and reduced latency to eat, indicating habituation. Females consumed more novel food than males and more novel than familiar food. Experiment 2 tested Pavlovian auditory fear conditioning, extinction, and renewal. Behavioral responses were categorized under freezing, mobility, or neutral behaviors. Freezing increased during acquisition, decreased during extinction, and was renewed in the original acquisition context, confirming learning and memory in both sexes. In contrast, mobility behaviors increased during extinction and were not conditioned nor renewed. Neutral behaviors were high at baseline and suppressed during cue presentations. Lower novel food consumption correlated with higher freezing and lower mobility during extinction in males, but not females. This suggests that individual differences in novelty-induced anxiety can predict behavior during fear extinction in male rats.