Positive affect increases aperiodic brain activity.

Area of Science:

• Cognitive Neuroscience
• Affective Neuroscience
• Computational Neuroscience

Background:

• Metacontrol, the ability to balance persistence and flexibility, is crucial for adaptive behavior.
• Cortical noise, measured by the aperiodic exponent of neural activity, is implicated in metacontrol.
• Behavioral studies suggest a link between affect and metacontrol, prompting investigation into their neural underpinnings.

Purpose of the Study:

• To investigate whether affective valence systematically alters aperiodic neural activity.
• To examine the relationship between processing affective facial expressions and the aperiodic exponent during a cognitive task.

Main Methods:

• Analysis of aperiodic neural activity using the aperiodic exponent.
• Participants performed a 2-back task involving presentation of negative, neutral, and positive facial expressions.
• Data were analyzed from two independent datasets, with a specific focus on blocked valence conditions.

Main Results:

• Whole-brain aperiodic activity was significantly higher for positive facial expressions compared to neutral and negative faces.
• This effect was observed specifically when affective valence was blocked (consistent over consecutive trials).
• The observed differences in aperiodic activity were widespread, including frontal, parietal, temporal, and occipital regions.

Conclusions:

• Aperiodic neural activity is modulated by affective valence.
• Processing positive stimuli leads to increased aperiodic activity compared to neutral or negative stimuli.
• These findings highlight the interplay between affect and neural dynamics underlying cognitive control.