Decreased Modulation of EEG Oscillations in High-Functioning Autism during a Motor Control Task

Area of Science:

• Neuroscience
• Developmental Psychology
• Biomedical Engineering

Background:

• Autism spectrum disorders (ASD) are associated with altered excitatory-inhibitory balance in the brain.
• This imbalance may affect neural oscillations, measurable via electroencephalogram (EEG).
• Praxis, the ability to plan and execute skilled movements, is linked to ASD symptoms.

Purpose of the Study:

• To investigate premotor-parietal cortical physiology during a praxis task in children with high-functioning ASD (HFA) compared to controls.
• To assess task-related modulation of alpha and beta frequency bands in EEG signals.
• To explore the relationship between altered oscillatory activity, imitation abilities, and autism severity.

Main Methods:

• EEG recordings were obtained from 25 children with HFA and 33 controls performing a tool-use pantomime task.
• Analysis focused on task-related modulation of signal power in alpha (7-13 Hz) and beta (18-22 Hz) frequency bands.
• Event-related desynchronization (ERD) was quantified in central (motor/premotor) and parietal regions.

Main Results:

• Children with HFA showed significantly less left central beta ERD (27%) and left parietal alpha ERD (24%) compared to controls.
• Within the HFA group, reduced central beta ERD was correlated with poorer praxis imitation and higher autism severity.
• These findings suggest altered modulation of oscillatory activity in motor networks.

Conclusions:

• Altered cortical excitatory-inhibitory balance in ASD may manifest as abnormal neural oscillations during praxis.
• Reduced beta and alpha ERD in HFA are associated with motor imitation deficits and core autism symptoms.
• Modulation of central beta activity, potentially related to motor imagery, is mechanistically implicated in ASD-related motor network dysfunction.