Stress within a restricted time window selectively affects the persistence of long-term memory

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Memory Research

Background:

• Stress differentially affects memory consolidation and reconsolidation.
• Previous studies focused on long-term memory (LTM) formation, with less known about LTM persistence.
• LTM persistence relies on late-phase protein synthesis in the dorsal hippocampus.

Purpose of the Study:

• To investigate the effects of stress on the persistence of contextual fear memory in rats.
• To examine stress during late consolidation (after acquisition) and late reconsolidation (after retrieval).
• To determine the role of the glucocorticoid system in stress-induced modulation of LTM persistence.

Main Methods:

• Rats were subjected to cold water stress during specific late phases after contextual fear memory acquisition or retrieval.
• Corticosterone administration and metyrapone (a corticosterone synthesis inhibitor) were used.
• Long-term memory persistence was assessed at least one week later.

Main Results:

• Stress during late consolidation (12h post-acquisition) enhanced LTM persistence.
• Stress during late reconsolidation (12h post-retrieval) disrupted LTM persistence.
• The effects of stress were blocked by metyrapone, indicating glucocorticoid system involvement.

Conclusions:

• Stress exposure during specific late phases after memory acquisition or retrieval selectively modulates LTM persistence.
• The glucocorticoid system is crucial for stress effects on LTM persistence.
• Timing of stress relative to memory events dictates its impact on memory persistence.