Long-interval intracortical inhibition in individuals with autism spectrum disorders: A TMS-EEG study with source...

This study aimed to evaluate Long-interval Intracortical Inhibition (LICI) in the Dorsolateral Prefrontal Cortex (DLPFC) of individuals with Autism Spectrum Disorder (ASD) using transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) with source-based estimation analyses.

We applied the LICI paradigm to the left DLPFC of 32 individuals with ASD and 34 healthy controls. First, sensor-level Local Mean Field Power (LMFP) was calculated from TMS-evoked potentials for all participants to detect the LICI effect. Subsequently, source-based analyses were performed using dynamic statistical parametric mapping to minimize the influence of volume conduction. Finally, time-frequency (TF) analyses at the source level were conducted to further characterize the LICI effects.

LMFP analysis revealed that cortical activity in the interval of 165-234 ms post-stimulation was suppressed by LICI (p = 0.024). Source-based analyses confirmed inhibitory effects within the same time range. Additionally, TF analyses indicated suppressive effects within 30-300 ms in the theta to alpha bands. However, no significant group differences in the LICI effects were detected.

TMS-EEG combined with LICI alone may be insufficient to detect GABA(B) receptor dysfunction in ASD.

This is the first TMS-EEG study to elucidate the LICI effect by applying source-estimation methods in ASD.