Investigating the role of E/I imbalance in auditory and language processing challenges in ASD: a potential pathway for intervention

Authors

• E Greenstein
• M Jaime
• S Dammalapati
• LM Oberman
• SM Francis
• J Stout
• S Van Der Veen
• SH Lisanby

Abstract

Auditory and language processing challenges are a hallmark of autism spectrum disorder (ASD) and a key contributor to the social communication challenges observed in this group. Despite the pervasive nature of these challenges, their etiology remains poorly understood, hindering the development of effective interventions.

Proposed theories include excitatory/inhibitory (E/I) imbalance and aberrations in structural and functional connectivity. This study investigates the relationship between local GABA concentration, network connectivity, and magnetoencephalography (MEG) measures of auditory and language processing in adolescents with ASD. Participants receive continuous theta burst stimulation (cTBS), a form of repetitive transcranial magnetic stimulation (rTMS), during which language-implicated regions of the brain are noninvasively modulated via short electromagnetic pulses for forty seconds. Its impact on GABA levels, connectivity, and MEG indices within a given individual is measured.

The healthy volunteer (pilot) phase of the study revealed that the ratio of excitatory (glutamate) to inhibitory (GABA) neurotransmitter concentrations is negatively correlated with a MEG index of auditory processing (M100 latency) at baseline. Additionally, correlations were also noted between pre- to post-cTBS changes in M100 latency and the GLU/GABA ratio change. These findings indicate that shifting the E/I balance towards greater inhibition may facilitate auditory processing, providing a critical foundation for the ongoing ASD (main) phase of the study.

This research extends existing theoretical models by incorporating a dynamic interventional component to the otherwise predominantly observational nature of previous studies, potentially paving the way for future therapeutic trials targeting GABA to treat ASD symptoms.

Scientific Focus Area: Neuroscience

This page was last updated on Tuesday, August 6, 2024