Persistent prelimbic cortex activity contributes to enhanced learned fear expression in females

Area of Science:

• Neuroscience
• Behavioral Science
• Psychiatry

Background:

• Anxiety disorders, including post-traumatic stress disorder (PTSD), disproportionately affect women.
• These disorders are associated with difficulties in inhibiting learned fear and dysfunction in the medial prefrontal cortex (mPFC).

Purpose of the Study:

• To investigate sex differences in fear extinction and medial prefrontal cortex (mPFC) activity in a rat model.
• To explore the neural mechanisms underlying heightened fear expression in females.

Main Methods:

• Fear conditioning and extinction paradigms were employed in male and female rats.
• Electrophysiological recordings were used to assess activity in the prelimbic (PL) cortex, a subregion of the mPFC.

Main Results:

• Female rats displayed greater learned fear expression during extinction and recall compared to males.
• Females exhibited increased spontaneous fear recovery and contextual fear.
• Sustained activity in the prelimbic (PL) cortex was correlated with enhanced learned fear expression in females.

Conclusions:

• Sex differences in learned fear expression and extinction are evident in rats.
• Persistent activation of the prelimbic (PL) cortex may underlie heightened fear responses and impaired fear inhibition in females.
• These findings contribute to understanding the neurobiological basis of sex differences in anxiety disorders.