Page 50 - MEGIN Book Of Abstracts - 2023

Department of Psychology, San Diego State University, Autonomic and Electrophysiological Evidence for
San Diego, CA 92182, USA; Department of Neurosciences, Reduced Auditory Habituation in Autism (2021)
University of California San Diego, San Diego, CA 92093, USA;
Joint Doctoral Program in Clinical Psychology, San Diego Gandhi, Tapan K; Tsourides, Kleovoulos; Singhal, Nidhi;
State University and University of California San Diego, San Cardinaux, Annie; Jamal, Wasifa; Pantazis, Dimitrios;
Diego, CA 92120, USA; Department of Radiology, University of Kjelgaard, Margaret; Sinha, Pawan
California San Diego, San Diego, CA 92093, USA
Department of Brain and Cognitive Sciences, Massachusetts
ABSTRACT Neuroimaging studies have revealed atypi- Institute of Technology, Cambridge, MA, 02139, USA. tgan-
cal activation during language and executive tasks [email protected]; Open Doors School, Action for Autism, New
in individuals with autism spectrum disorders (ASD). Delhi, 110 054, India; Communication Sciences and Disor-
However, the spatiotemporal stages of processing asso- ders, Bridgewater State University, Bridgewater, MA, 02325,
ciated with these dysfunctions remain poorly under- USA; Department of Brain and Cognitive Sciences, Massa-
stood. Using an anatomically constrained magnetoen- chusetts Institute of Technology, Cambridge, MA, 02139, USA.
cephalography approach, we examined event-related [email protected]
theta oscillations during a double-duty lexical decision
task that combined demands on lexico-semantic pro- ABSTRACT It is estimated that nearly 90% of children
cessing and executive functions. Relative to typically on the autism spectrum exhibit sensory atypicalities.
developing peers, high-functioning adolescents with What aspects of sensory processing are affected in
ASD had lower performance accuracy on trials engag- autism? Although sensory processing can be studied
ing selective semantic retrieval and cognitive control. along multiple dimensions, two of the most basic ones
They showed an early overall theta increase in the left involve examining instantaneous sensory responses
fusiform cortex followed by greater activity in the left- and how the responses change over time. These cor-
lateralized temporal (starting at ~250 ms) and frontal respond to the dimensions of 'sensitivity' and 'habitu-
cortical areas (after ~450 ms) known to contribute to ation'. Results thus far have indicated that autistic
language processing. During response preparation individuals do not differ systematically from controls in
and execution, the ASD group exhibited elevated theta sensory acuity/sensitivity. However, data from studies
in the anterior cingulate cortex, indicative of greater of habituation have been equivocal. We have studied
engagement of cognitive control. Simultaneously habituation in autism using two measures: galvanic
increased activity in the ipsilateral motor cortex may skin response (GSR) and magneto-encephalography
reflect a less lateralized and suboptimally organized (MEG). We report data from two independent studies.
motor circuitry. Spanning early sensory-specific and The first study, was conducted with 13 autistic and 13
late response selection stages, the higher event-related age-matched neurotypical young adults and used GSR
theta responsivity in ASD may indicate compensa- to assess response to an extended metronomic se-
tory recruitment to offset inefficient lexico-semantic quence. The second study involved 24 participants (12
retrieval under cognitively demanding conditions. with an ASD diagnosis), different from those in study 1,
Together, these findings provide further support for spanning the pre-adolescent to young adult age range,
atypical language and executive functions in high- and used MEG. Both studies reveal consistent patterns
functioning ASD. of reduced habituation in autistic participants. These
results suggest that autism, through mechanisms that
Keywords: MEG, Theta oscillations, autism, cognitive are yet to be elucidated, compromises a fundamental
control, language aspect of sensory processing, at least in the auditory
domain. We discuss the implications for understanding
Cerebral cortex (New York, N.Y.: 1991) (2021), Vol. 31, No. 2 sensory hypersensitivities, a hallmark phenotypic fea-
(33073290) (1 citation) ture of autism, recently proposed theoretical accounts,

 ontents  Index 29
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