Dissociating effects of acute photic stress on spatial, episodic-like and working memory in the rat

Johannes Passecker,Sally Barlow,Shane M O’Mara

doi:10.1016/j.bbr.2014.07.007

Abstract

Adaptively responding to acute stress has been of great importance for human and animal survival. However, for our species, stress-related disorders are putting an ever-increasing burden on healthcare systems. It is thus crucial to understand the basic processes and cognitive changes associated with acute stress. Here, we examined the effects of acute stress exposure on spatial (water maze) and memory (delayed match to sample and episodic-memory-like tasks) performance. We found striking performance deficits in stressed animals navigating in the water maze. We also found, in an episodic-like memory task, striking object-location deficits, but not in temporal-object association learning in stressed animals. Finally, no differences were apparent for any delay periods (up to 30s) in a delayed match to sample task. Taken together, these results show a strong differential effect of acute stress on differing memory processes.

Highlights

The physiological response to acute stressors – the acute stress response – serves a variety of adaptive responses
We focus in particular on the normalization phase of the acute stress response, where the brain is thought to recover from the acute stress exposure
We find striking performance decrements on the water maze and the episodic-like memory task but not the working memory task after exposure to acute stress

Summary

Introduction

The physiological response to acute stressors – the acute stress response – serves a variety of adaptive responses. A sustained stress response may cause a variety of deleterious effects. Many studies have shown deleterious effects of stress, especially of an acute nature on cognition in humans and rodents alike (for review see [1], [2], [3] and [4]). We examine the effects of acute stress on a variety of cognitive processes, in order to better understand how stress may differentially affect differing functions. We focus in particular on the normalization phase of the acute stress response, where the brain is thought to recover from the acute stress exposure (for review, see [1]). Our aim was to characterize in detail the behavioral changes associated with this phase by introducing a 30 min break after the stress exposure, and before testing animals in the various memory tasks

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