Abnormal Connectivity Involving the Social Reciprocity Network in Autism and the Impact of Neurostimulation in Mitigating the Abnormalities

Autism spectrum disorder (ASD) encompasses a range of limitations in reciprocal and communicative milestones, leading to significant functional challenges throughout the lifespan. While there is no consensus regarding the neuroanatomical substrate underpinning ASD, there are two major schools of thought: a group of researchers have focused on abnormalities affecting the mirror neurons and other cortical areas involved in social reciprocity, while others have proposed a more widespread alteration in neuronal organization in this condition resulting in abnormal white matter trajectories leading to cortical over or under connectivity. The investigators describe the social reciprocity network: the mirror neurons populated in the inferior frontal gyrus (IFG) and inferior parietal lobule (IPL), plus cortical areas involved in abstract social cognition including the medial prefrontal cortex, temporal-parietal junction and posterior cingulate gyrus. We hypothesize that aberrant connectivity affecting the above neuronal circuitry, "the social reciprocity network" contributes significantly to the core deficits in this condition.

Quantitative electroencephalography (QEEG) coherence and spectral power analysis are reliable measures of functional connectivity and neuronal dynamics. The investigators aim to study the QEEG coherence/spectral power analysis to explore the abnormal neuronal dynamics affecting the social reciprocity network in ASD. The existing literature suggest that noninvasive brain modulation, via Repetitive transcranial magnetic stimulation (rTMS), could potentially ameliorate the aberrant connectivity and the behaviors in ASD by altering neuronal dynamics. The investigator's overarching goal is to explore the neuronal connectivity in the social reciprocity network and to elucidate the mechanism of modulating these connections in improving social cognition in ASD.

Within this design, there are 3 aims:

Aim 1: Exploring the QEEG measures of connectivity and oscillatory patterns in the social reciprocity network in ASD. Hypothesis: abnormal connectivity affecting the social reciprocity network contributes to the core deficits in ASD.

Aim 2: Assessing the effects of rTMS of the bilateral social reciprocity network on the connectivity/spectral analysis as well as social cognition in ASD. Hypothesis: neurostimulation of the social reciprocity network ameliorates social cognition, power densities and the functional connectivity within the network.