Recovery after chronic stress within spatial reference and working memory domains: correspondence with hippocampal...

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Stress Research

Background:

• Chronic stress is known to cause reversible spatial learning deficits.
• These deficits correlate with structural changes in hippocampal CA3 dendrites.
• The impact of chronic stress on different memory domains and their recovery is not fully understood.

Purpose of the Study:

• To investigate the effects of chronic stress on spatial reference and working memory.
• To determine if stress-induced memory deficits and dendritic changes are reversible.
• To explore potential long-term effects of chronic stress on memory and hippocampal structure.

Main Methods:

• Male Sprague-Dawley rats were divided into control, immediate stress, and delayed stress groups.
• Chronic stress involved 21 days of restraint (6 h/day).
• Radial arm water maze (RAWM) was used to assess spatial reference and working memory, with testing occurring immediately or 21 days after stress cessation.

Main Results:

• All groups learned the RAWM task similarly.
• Immediate stress (STR-IMM) induced spatial reference and working memory deficits, linked to reduced hippocampal CA3 dendritic complexity.
• Delayed stress (STR-DEL) showed fewer errors than STR-IMM and even improved reference memory compared to controls, with restored CA3 dendritic complexity.

Conclusions:

• Chronic stress-induced spatial memory impairments and CA3 dendritic retraction are reversible.
• A delay following chronic stress can lead to lasting benefits in spatial reference memory.
• These long-term beneficial effects appear independent of hippocampal CA3 dendritic complexity.