Date of Award

January 2020

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

James McPartland

Abstract

Abstract

Noninvasive brain stimulation of the posterior superior temporal sulcus modulates neural response and visual attention to faces in autism spectrum disorder

Melissa S. Zhou1, Adam Naples1, Scott J. Jackson1, Armen Bagdasarov1, Carter Carlos1, Shashwat Kala1, Elise Cummings1, Melody R. Altschuler1, Morgan McNair1, Takumi McAllister1, Christine C. Cukar-Capizzi1, Julie Wolf1 and James McPartland1

(1) Child Study Center, Yale University School of Medicine, New Haven, CT, USA

The superior temporal sulcus (STS) plays an important role in the perception of faces and biological motion. The STS contributes to the generation of a face-sensitive event-related potential (ERP), the N170, which is delayed in autism spectrum disorder (ASD). The STS also plays a role in regulating visual attention to the face, which is decreased in individuals with ASD. Intermittent theta burst stimulation (iTBS), an excitatory form of noninvasive brain stimulation, to the STS has not been effectively explored in individuals with ASD in terms of its potential influence on these biomarkers. The objective of this study was to investigate changes induced by iTBS to the right posterior STS (rpSTS) in N170 latency to faces and proportion of fixation (POF), as measured by eye-tracking (ET), to socially relevant facial features in adults with ASD compared to typically developing (TD) adults. We predicted that a single session of iTBS to the rpSTS would decrease N170 latency to faces and increase POF to eyes. The study included four adults with ASD (mean age = 28.0 years) and seven TD adults (mean age = 30.1 years). ASD diagnosis was based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), Autism Diagnostic Observation Schedule (ADOS), and Autism Diagnostic Interview, Revised (ADI-R) criteria. iTBS was administered to the rpSTS (mapped as T6/P8 in the 10-20 EEG coordinate system). Stimulation was delivered in 2 second (s) trains every 10s for a total of 190s (600 pulses) at an intensity of 80% of the active motor threshold. EEG and ET data were collected before and after the iTBS session. Participants were instructed to look naturally at presented static faces and houses after initial guided fixation (via a crosshair) on facial regions of interest (left eye, right eye, nose or mouth) and corresponding regions of house stimuli. The latencies of the N170 [in milliseconds(ms)] were extracted from selected occipitotemporal electrodes and segmented to onset of face stimuli. POF to eyes on faces was calculated as the number of gaze samples within the eye-region of the face divided by the total number of on-screen gaze samples. In individuals with ASD, iTBS to the rpSTS significantly decreased N170 latency to faces (mean difference Post-Pre ± standard deviation (SD) = -4.8 ± 5.6, Cohen’s d = -0.49; p < 0.05). Increased POF to eyes was observed but did not attain statistical significance (mean difference Post-Pre ± SD = 6.9 ms ± 13.4, Cohen’s d = 0.23; p = 0.26). Results suggest that iTBS to the rpSTS may increase efficiency of social brain activity in individuals with ASD, supporting the potential utility of TMS as a brain-based intervention for the core social symptoms of ASD. This preliminary work lays a foundation for replication in larger samples.

Comments

This thesis is restricted to Yale network users only. This thesis is permanently embargoed from public release.

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