Dynamic functional connectivity in the right temporoparietal junction captures variations in male autistic trait expression

Autistic individuals can experience difficulties with attention reorienting and Theory of Mind (ToM), which are closely associated with anterior and posterior subdivisions of the right temporoparietal junction. While the link between these processes remains unclear, it is likely subserved by a dynamic crosstalk between these two subdivisions. We, therefore, examined the dynamic functional connectivity (dFC) between the anterior and posterior temporoparietal junction, as a biological marker of attention and ToM, to test its contribution to the manifestation of autistic trait expression in Autism Spectrum Condition (ASC). Two studies were conducted, exploratory (14 ASC, 15 TD) and replication (29 ASC, 29 TD), using resting-state fMRI data and the Social Responsiveness Scale (SRS) from the Autism Brain Imaging Data Exchange repository. Dynamic Independent Component Analysis was performed in both datasets using the CONN toolbox. An additional sliding-window analysis was performed in the replication study to explore different connectivity states (from highly negatively to highly positively correlated). Dynamic FC was reduced in ASC compared to TD adults in both the exploratory and replication datasets and was associated with increased SRS scores (especially in ASC). Regression analyses revealed that decreased SRS autistic expression was predicted by engagement of highly negatively correlated states, while engagement of highly positively correlated states predicted increased expression. These findings provided consistent evidence that the difficulties observed in ASC are associated with altered patterns of dFC between brain regions subserving attention reorienting and ToM processes and may serve as a biomarker of autistic trait expression. Autistic individuals may have difficulties with redirecting their attention and understanding others' thoughts and it is possible that there is a direct link between the interaction of these two functions and the level of social difficulties in autism. One way to test this link is by assessing how different brain regions associated with these functions are communicating with each other and working in synchrony. The present study focused on two subdivisions of a brain region called the temporoparietal junction, which has been associated with attention and understanding others' thoughts. Our aim was to assess the dynamic communication between these subdivisions in autistic and non-autistic individuals and whether differences in this dynamic communication might be related to higher or lower expressions of social difficulties. Using brain scans from two different groups of 29 and 58 participants, we found that communication between these brain regions was less dynamic in autistic individuals in both groups. Moreover, reduced dynamic communication between these two subdivisions of the temporoparietal junction was associated with greater social difficulties. Across the two groups, we show consistent results whereby some of the social difficulties observed in autistic individuals might arise from reduced dynamic communication between brain areas linked to attention and understanding of others' thoughts. This insight adds to our understanding of how the spectrum of autistic traits might be rooted in the brain's communication patterns and advances the search for biological markers of autism.