Unraveling Sex Differences in Affect Processing: Unique Oscillatory Signaling Dynamics in the Infralimbic Cortex and...

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Psychiatric Research

Background:

• Negative affect is common in psychiatric disorders such as depression and addiction.
• The infralimbic cortex (IL) to nucleus accumbens shell (NAcSh) circuit is involved in learned negative affect.
• Previous research showed sex differences in this circuit's response to aversion learning.

Purpose of the Study:

• To investigate sex-specific processing of innate and learned negative affect in the IL and NAcSh.
• To examine local field potential (LFP) activity in response to rewarding and aversive stimuli and during conditioned taste aversion (CTA).

Main Methods:

• Simultaneous recording of LFP activity in the IL and NAcSh of male and female Sprague Dawley rats.
• Infusion of rewarding (saccharin) and aversive (quinine) tastants.
• Induction of a CTA.

Main Results:

• Sex-specific oscillatory activity in the IL and NAcSh in response to saccharin.
• CTA altered IL resting-state power and IL-NAcSh coherence in males, correlating with aversion strength.
• CTA increased NAcSh gamma power in females and affected theta-low gamma phase-amplitude coupling in both sexes.
• Females exhibited distinct NAcSh phase-amplitude coupling to quinine, potentially related to aversion resistance.

Conclusions:

• This study uncovered sex-specific hedonic processing in the IL and NAcSh.
• Oscillatory signaling disruptions in learned negative affect were identified, offering translational insights.
• Findings suggest potential therapeutic strategies for mitigating learned negative affect in psychiatric illnesses.