Differential phase-amplitude coupling in nucleus accumbens and orbitofrontal cortex reflects decision-making during a...

Area of Science:

• Neuroscience
• Decision-making research
• Behavioral economics

Background:

• Impulsive choice involves preferring immediate rewards over larger, delayed ones.
• Neural mechanisms of impulsivity involve the Nucleus Accumbens (NAc), orbitofrontal cortex (OFC), and dorsolateral striatum (DLS).
• Functional connectivity's role in distinguishing impulsive vs. self-control decisions is not well understood.

Purpose of the Study:

• To investigate functional connectivity differences between and within the NAc, OFC, and DLS during a delay discounting task.
• To determine if specific patterns of neural activity differentiate between high and low tendencies for impulsive choices.

Main Methods:

• Concurrent local field potential recording in the NAc, OFC, and DLS of rats during a delay discounting task.
• Quantification of phase-amplitude coupling (PAC), coherence, and Granger Causality between oscillatory activities.
• Comparison of neural activity in rats with high (HI) vs. low (LI) impulsive choice tendencies.

Main Results:

• Differential PAC patterns observed in the OFC and NAc, but not DLS, during decision-making.
• Theta-gamma PAC in OFC correlated with self-control; higher delta-gamma PAC in OFC and NAc correlated with impulsive choices.
• Granger Causality revealed stronger NAc➔OFC gamma contribution in HI group and OFC➔NAc gamma contribution in LI group during reward events.

Conclusions:

• Overactivity in the NAc during reward in the high impulsivity group suggests its core contributes to reward overvaluation.
• Altered functional connectivity, particularly delta-gamma PAC in OFC and NAc, underlies biased impulsive behavior.
• These findings elucidate neural underpinnings differentiating impulsive choices from self-control.