Moaddab, M. | Search bioRxiv

bioRxiv2020

Foot shock facilitates reward seeking in an experience-dependent manner

Animals organize reward seeking around aversive events. An abundance of research shows that foot shock, as well as a shock-associated cue, can elicit freezing and suppress reward seeking. Yet, there is evidence that experience can flip the effect of foot shock to facilitate reward seeking. Here we examine cue suppression, foot shock suppression and foot shock facilitation of reward seeking in a single behavioural setting. Male Long Evans rats received fear discrimination consisting of danger, uncertainty and safety cues. Discrimination took place over a baseline of rewarded nose poking. With limited experience, all cues and foot shock strongly suppressed reward seeking. With continued experience, suppression became specific to shock-associated cues and foot shock facilitated reward seeking. Our results provide a means of assessing positive properties of foot shock, and may provide insight into maladaptive behavior around aversive events.Competing Interest StatementThe authors have declared no competing interest.View Full Text

animal behavior and cognition↗

bioRxiv2020

Ventral pallidum neurons signal relative threat

Ventral pallidum (VP) neurons scale firing increases to reward value and decrease firing to aversive cues. Anatomical connectivity suggests a critical role for the VP in threat-related behavior. Here we tested whether firing decreases in VP neurons conform to relative threat by recording single units while male rats discriminated cues predicting unique foot shock probabilities. Rats behavior and VP single unit firing discriminated danger, uncertainty and safety cues. We found that two VP populations (Low firing and Intermediate firing) signaled relative threat, proportionally decreased firing according shock probability: danger < uncertainty < safety. Low firing neurons showed reward firing increases, consistent with a general signal for relative value. Intermediate firing neurons were unresponsive to reward, revealing a specific signal for relative threat. The results suggest an integral role for the VP in threat-related behavior.

neuroscience↗