Reducing shock imminence eliminates poor avoidance in rats

Abstract

In signaled active avoidance (SigAA), rats learn to suppress Pavlovian freezing and emit actions to escape threats and prevent footshocks. SigAA is critical for understanding aversively-motivated instrumental behavior and anxiety-related active coping. However, with standard protocols ~25% of rats exhibit high freezing and poor avoidance. This has dampened enthusiasm for the paradigm and stalled progress. We demonstrate that reducing shock imminence with long-duration warning signals leads to greater freezing suppression and perfect avoidance in all subjects. This suggests that instrumental SigAA mechanisms evolved to cope with distant harm and protocols that promote inflexible Pavlovian reactions are poorly-designed to study avoidance.

The bed nucleus of the stria terminalis mediates the expression of proactive defensive behavior

“…Recent empirical 50 and theoretical 51 work argues that two-way avoidance should be categorized as a pre-encounter defensive behavior within the framework of threat imminence theory, an important conceptual tool for understanding conditioned aversion from the perspective of predator/prey dynamics in natural settings 6 . A threat imminence approach to SAA draws on ecological models of predatory defense that place proactive/preventative avoidance measures at a time point in predator/prey interactions occurring before the predator has been directly encountered, when the threat of attack is relatively distant 7,8,52 .…”