The development of aperiodic neural activity in the human brain

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• Brain maturation continues into adulthood, impacting cognitive functions like attention and memory.
• Neurophysiological mechanisms, particularly the excitation-inhibition (E:I) balance, are crucial for cognitive development.
• Aperiodic activity, quantified by slope, serves as a proxy for E:I balance in the brain.

Purpose of the Study:

• To map the developmental trajectories of aperiodic activity across widespread brain regions using intracranial EEG (iEEG).
• To investigate how age and cognitive state (task-based vs. resting-state) influence E:I balance in different cortical regions.
• To link neurophysiological development, specifically PFC inhibitory control, to age-related improvements in memory performance.

Main Methods:

• Analysis of intracranial EEG (iEEG) recordings from 101 participants (5.93-54.00 years) during task-based and resting-state conditions.
• Quantification of aperiodic activity slopes as a proxy for excitation-inhibition (E:I) balance across various brain regions.
• Integration of structural imaging data to examine the relationship between gray matter volume and neural activity slopes.

Main Results:

• Aperiodic slopes flatten with age into young adulthood in association and sensorimotor cortices, indicating a shift in E:I balance.
• In the prefrontal cortex (PFC), attentional state differentially affects age-related slope changes, reflecting developing cognitive control.
• Age-related changes in task-based PFC activity slopes significantly predicted memory performance gains.

Conclusions:

• Developmental trajectories of aperiodic activity reveal region-specific maturation patterns of E:I balance.
• Adolescent development of PFC inhibitory control, indicated by task-based aperiodic slopes, is critical for attention and memory development.
• Neural maturation, as reflected by aperiodic activity, is linked to structural brain development and cognitive function across the lifespan.