Lobular patterns of cerebellar resting‐state connectivity in adults with Autism Spectrum Disorder

Abstract

Autism spectrum disorder is a neurodevelopmental disorder characterized by core deficits in social functioning. Core autistics traits refer to poor social and imagination skills, poor attention-switching/strong focus of attention, exceptional attention to detail, as expressed by the autism-spectrum quotient. Over the years, the importance of the cerebellum in the aetiology of autism spectrum disorder has been acknowledged. Neuroimaging studies have provided a strong support to this view, showing both structural and functional connectivity alterations to affect the cerebellum in autism spectrum disorder. According to the underconnectivity theory, disrupted connectivity within cerebello-cerebral networks has been specifically implicated in the aetiology of autism spectrum disorder. However, inconsistent results have been generated across studies. In this study, an integrated approach has been used in a selected population of adults with autism spectrum disorder to analyse both cerebellar morphometry and functional connectivity. In individuals with autism spectrum disorder, a decreased cerebellar grey matter volume affected the right Crus II, a region showing extensive connections with cerebral areas related to social functions. This grey matter reduction correlates with the degree of autistic traits as measured by autism-spectrum quotient. Interestingly, altered functional connectivity was found between the reduced cerebellar Crus II and contralateral cerebral regions, such as frontal and temporal areas. Overall, the present data suggest that adults with autism spectrum disorder present with specific cerebellar structural alterations that may affect functional connectivity within cerebello-cerebral modules relevant to social processing and account for core autistics traits.

The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

“…Recent resting-state fMRI studies in ASD reveal altered functional connectivity between the dentate nucleus and the cerebral cortex [119] and decreased volume in right Crus II that correlates with the degree of autistic traits. Right Crus II is interconnected with contralateral frontal and temporal areas related to social cognition, and altered functional connectivity has been reported between the smaller Crus II and these cerebral areas [277]. In the Tsc1 (tuberous sclerosis) mouse model of ASD, neuromodulation of right Crus I (hemispheric extension of lobule VIIA) rescued social deficits, consistent with the suggestion that the dysfunction of cerebro-CB circuits underlies selected aspects of disrupted behavior in ASD [278].…”

Functional Changes of Mentalizing Network in SCA2 Patients: Novel Insights into Understanding the Social Cerebellum

“…Further evidence has been provided by RS-fMRI studies in subjects with autism spectrum disorders (ASD) [19][20][21][22], who typically experience social dysfunctions, showing altered FC within cerebellocerebral mentalizing networks. Through these circuits, cerebellar dysfunction may affect key social brain regions and impact the social functioning.…”

Explorations and perspectives on the neurobiological bases of autism spectrum disorder

“…provide reviews of the pathophysiology of two comorbid symptoms that have been strongly associated with ASD, namely deficits in oculomotor plasticity and epilepsy (Bozzi et al ., ; Freedman & Foxe, ). Oculomotor plasticity or saccadic eye movement adaptation is controlled in part by the cerebellum, a brain region often implicated in ASD [see (Olivito et al ., ) in this volume (Hampson & Blatt, ) but also see (Traut et al ., )]. In their review, Freedman and Foxe explore the link between saccadic eye movement adaptation and ASD.…”

“…In keeping with this theme of possible cerebellar dysfunction in ASD, Olivito et al . () show decreased cerebellar grey matter in the right Crus II in a small cohort of adults with ASD, and in turn, show reduced functional connectivity between this region and multiple distributed cortical regions. It will be of significant interest in future work to determine whether eye movement deficits in ASD can be related directly to cerebellar structural and functional measures.…”