Activity in prelimbic cortex subserves fear memory reconsolidation over time.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Memory Research

Background:

• The prelimbic cortex (PL) is involved in consolidating learned fear.
• Fear memory maintenance and reconsolidation are critical areas of study.

Purpose of the Study:

• To investigate the role of the prelimbic cortex in the reconsolidation of contextual fear memories of varying ages.
• To determine if prelimbic cortex inactivation disrupts fear memory maintenance.

Main Methods:

• Rats with 1-, 7-, or 21-day-old contextual fear memories were tested.
• Temporary inactivation of the prelimbic cortex was achieved using muscimol, a GABAA agonist.
• Fear memory retrieval and reactivation protocols were employed, with and without memory reactivation.
• Zif268/Egr1 gene expression was measured in prelimbic and infralimbic cortices.

Main Results:

• Prelimbic cortex inactivation disrupted fear memories regardless of age (1, 7, 21 days) after retrieval.
• Disruption of fear memory was prevented when memory reactivation was omitted.
• The disruptive effect persisted for over 11 days and lacked extinction features.
• Infralimbic cortex inactivation did not disrupt fear memory, and Zif268/Egr1 expression was lower compared to the prelimbic cortex.

Conclusions:

• The prelimbic cortex is crucial for the reconsolidation and maintenance of reactivated fear memories.
• Both recent and remote fear memories are susceptible to disruption via prelimbic cortex inactivation during reconsolidation.
• Findings highlight the prelimbic cortex's role in reestablishing and sustaining aversive memories over time.