Presentation

Search Abstracts | Symposia | Slide Sessions | Poster Sessions | Poster Slams

Exploring functional and structural language differences in autism spectrum disorder

Poster C54 in Poster Session C, Friday, October 7, 10:15 am - 12:00 pm EDT, Millennium Hall

Daniela Santana¹, Saskia B.J. Koch¹, Margot Mangnus¹, Ivan Toni¹, Arjen Stolk^1,2, Jana Bašnáková¹; ¹Donders Center for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands, ²Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA

While autism spectrum disorder (ASD) is characterized by difficulties in everyday communicative language use (Vulchanova et al, 2015), evidence from a limited number of neuroimaging studies suggests that language processing itself may also be altered, in at least a subset of this population (Mody and Belliveau, 2013). Functionally, autistic individuals have been documented to show relatively greater recruitment of right hemisphere homologues of the language network than neurotypical (NT) individuals, amounting to atypical functional lateralization in ASD (Jouravlev et al., 2020). Structurally, there have been reports of anatomical alterations in the ASD language network, though the alterations have not been directly associated with language processing (Ecker et al., 2013). The current study aims to expand upon prior suggestions of atypical language processing in ASD by integrating functional lateralization and anatomical asymmetry in ASD, with structural magnetic resonance imaging (MRI) data from a sample of 41 adults with ASD and 35 controls (matched in verbal IQ). First, we attempted to replicate prior observations of reduced lateralization in ASD, using a language localizer task designed to reliably activate the language network (sentences > non-word sequences; adapted from Fedorenko et al., 2010). Second, an analysis of gray matter asymmetry will be performed to test for a possible association between functional and structural language differences. Preliminary behavioral results indicate that both groups covered the attention and memory demands of the task equally well, as shown by the high accuracy of the task. As expected, processing word sequences activated brain regions commonly associated with the language network in all participants. More precisely, activation was observed in the inferior frontal gyrus and temporal regions of the left hemisphere, as well as temporal regions in the right hemisphere, with no differences between groups. These findings will need to be confirmed with Bayesian inference. Furthermore, our early results are not supportive of atypical functional lateralization across the ASD group. There were no significant differences in the degree of lateralization between groups (measure based on lateralization index, Jouravlev et al., 2020) (MASD = 0.491; MNT = 0.605; p = 0.319). The results of a multiple regression analysis with verbal IQ and autism quotient scores (AQ, Baron-Cohen et al., 2001) further suggest that the lack of differences cannot be ascribed to variation in language ability or autistic traits of participants. An ongoing analysis focuses on exploring gray matter asymmetry in ASD. More specifically, voxel-based morphometry (VBM) analyses will be conducted to investigate group differences in gray matter volume across hemispheres. Autism spectrum disorder is a complex disorder with marked differences in language production and comprehension, driven by alterations in the brain. Integrating functional and structural levels of analysis may provide a new angle on these differences.

Topic Areas: Disorders: Developmental, Meaning: Lexical Semantics