Altered Onset Response Dynamics in Somatosensory Processing in Autism Spectrum Disorder

Area of Science:

• Neuroscience
• Autism Spectrum Disorder Research
• Sensory Processing

Background:

• Autism spectrum disorder (ASD) is linked to cortical connectivity and response abnormalities.
• Previous research shows conflicting patterns of increased and decreased connectivity and response amplitudes.
• A prior hypothesis suggested reduced feedback (top-down) and increased feedforward (bottom-up) connectivity in ASD.

Purpose of the Study:

• To investigate abnormalities in the early, feedforward-driven component of cortical responses in the somatosensory cortex of individuals with ASD.
• To examine the spatio-temporal characteristics of cortical activation onset in response to vibrotactile stimuli.

Main Methods:

• Utilized magnetoencephalography (MEG) data to analyze brain activity.
• Applied a novel method to measure spatio-temporal divergence of cortical activation.
• Assessed responses to vibrotactile stimuli in the somatosensory cortex.

Main Results:

• The autism spectrum disorder (ASD) group exhibited an increased initial onset component of the cortical response compared to typically developing participants.
• A faster spread of local cortical activity was observed in the ASD group.
• These findings occurred within an early time window, characteristic of feedforward processing.

Conclusions:

• The results suggest increased thalamocortical feedforward connectivity in individuals with autism spectrum disorder (ASD).
• This heightened feedforward connectivity may explain previously observed response variability in ASD.
• The findings offer a potential mechanism for the tactile processing abnormalities commonly seen in autism spectrum disorder (ASD).