Differences in Cortical Structure and Functional MRI Connectivity in High Functioning Autism

Abstract

Autism spectrum disorders (ASD) represent a complex group of neurodevelopmental conditions characterized by deficits in communication and social behaviors. We examined the functional connectivity (FC) of the default mode network (DMN) and its relation to multimodal morphometry to investigate superregional, system-level alterations in a group of 22 adolescents and young adults with high-functioning autism compared to age-, and intelligence quotient-matched 29 healthy controls. The main findings were that ASD patients had gray matter (GM) reduction, decreased cortical thickness and larger cortical surface areas in several brain regions, including the cingulate, temporal lobes, and amygdala, as well as increased gyrification in regions associated with encoding visual memories and areas of the sensorimotor component of the DMN, more pronounced in the left hemisphere. Moreover, patients with ASD had decreased connectivity between the posterior cingulate cortex, and areas of the executive control component of the DMN and increased FC between the anteromedial prefrontal cortex and areas of the sensorimotor component of the DMN. Reduced cortical thickness in the right inferior frontal lobe correlated with higher social impairment according to the scores of the Autism Diagnostic Interview-Revised (ADI-R). Reduced cortical thickness in left frontal regions, as well as an increased cortical thickness in the right temporal pole and posterior cingulate, were associated with worse scores on the communication domain of the ADI-R. We found no association between scores on the restrictive and repetitive behaviors domain of ADI-R with structural measures or FC. The combination of these structural and connectivity abnormalities may help to explain some of the core behaviors in high-functioning ASD and need to be investigated further.

Shared and distinct patterns of atypical cortical morphometry in children with autism and anxiety

“…Our regional analysis harnessed MRI-based cortical thickness measures, a reliable technique that has previously been applied to profile morphological variations across a broad spectrum of typical and atypical neurodevelopment (Raznahan et al, 2011). Surface-wide comparisons between ASD and TDC revealed increased cortical thickness in the former, with strongest effects in temporal and posterior midline regions, together with tendencies for prefrontal thickening, which is consistent with prior surface-and voxel-based data suggestive of diffuse grey matter increases in individuals with ASD (Bedford et al, 2019;Hong et al, 2017;Khundrakpam et al, 2017;Pereira et al, 2018;Raznahan et al, 2010;Scheel et al, 2011;Valk et al, 2015;Wallace et al, 2010). Although the ASD and TDC differences resembled those seen when comparing individuals with ANX to TDC, confirmed by spin tests that control for the shared spatial autocorrelations in two surface-based maps (Alexander-Bloch et al, 2018), ANX presented with a different distribution of anomalies with increased cortical thickness in frontoinsular-opercular regions while temporal and midline parietal were only visible at uncorrected significance level.…”

“…Cortical thickness provides biologically meaningful insight regarding the cellular and synaptic organization of the cortex (Desrivieres et al, 2014;Huttenlocher, 1979;Schuz and Palm, 1989). Previous studies have reported varied patterns and directions of cortical anomalies in ASD relative to typically developing controls (TDC) (Khundrakpam et al, 2017;Redcay, 2007;Pereira et al, 2018;Raznahan et al, 2010;Scheel et al, 2011;Wallace et al, 2010); however, recent large-scale studies based on open datasets have generally converged on increased thickness in frontal and temporal cortical areas in individuals with ASD (Bedford et al, 2019;Hong et al, 2017;Valk et al, 2015). Studies assessing cortical morphology in ANX have also pointed to increased cortical thickness in medial and lateral frontal regions relative to TDC (Gold et al, 2017;Strawn et al, 2014), with, however, a seemingly different spatial topography compared to ASD.…”

Connectome and microcircuit models implicate atypical subcortico-cortical interactions in autism pathophysiology

“…A major difficulty in the neurobiological understanding of autism is that the condition impacts multiple scales of brain organization [4][5][6][7][8][9][10] . Contemporary neuroimaging studies suggested that autism is characterized by both macroscale anomalies in brain connectivity [6][7][8][10][11][12][13][14] and local changes in microcircuit function such as excitation/inhibition imbalance 4,5,9,[15][16][17] . However, we currently lack an overarching framework that can bridge the topographical changes at macroscale and microscale dysfunctions in autism pathophysiology.…”

“…Systems neuroscience has recently gained unprecedented opportunities to interrogate the human brain at multiple scales in both health and disease 4,6,8,9,18 . Although a wealth of studies in autism spectrum conditions have examined local disturbances in cortical morphology 12,19 and functional connectivity 6,10,14,20,21 as well as mesoscale functional miswiring [22][23][24][25] , less is known about macroscopic changes in structural connectivity [26][27][28][29] . Previous studies observed atypical diffusivity parameters and streamline connections in local brain regions and pathways in autism 27,28 .…”

Prediction of Treatment Outcome for Autism from Structure of the Brain Based On Sure Independence Screening

“…Structural changes of the brain have been identified in patients with ASD in the literature: Sparks et al found children with ASD have significantly in-creased cerebral volumes compared with typically developing (TD) and delayed developing (DD) children [2]. Pereira et al found changes in cingulate gyrus, paracentral lobule and superior frontal gyrus on subjects with ASD [3].…”