Towards robust and replicable sex differences in the intrinsic brain function of autism

BackgroundChanges in the brain’s default mode network (DMN) in the resting state are closely related to autism spectrum disorder (ASD). Module segmentation can effectively elucidate the neural mechanism of ASD and explore the intra- and internetwork connections by means of the participation coefficient (PC).MethodsResting-state fMRI data from 269 ASD patients and 340 healthy controls (HCs) were used in the current study. The PC of brain network modules was calculated and compared between ASD subjects and HCs. In addition, we further explored the features according to different age groups and different subtypes of ASD. Intra- and internetwork differences were further calculated to find the potential mechanism underlying the results.ResultsASD subjects showed significantly higher PC of the DMN than HC subjects. This difference was caused by lower intramodule connections within the DMN and higher internetwork connections between the DMN and networks. When the subjects were split into age groups, the results were verified in the 7-12 and 12-18 age groups but not in the adult group (18-25). When the subjects were divided according to different subtypes of ASD, the results were also observed in the classic autism and pervasive developmental disorder groups, but not in the Asperger disorder group. In addition, compared with the HC group, the ASD group showed significantly increased intranetwork connections between the DMN and the frontoparietal network.ConclusionsLess developed network segregation in the DMN could be a valid biomarker for ASD, and this feature was validated with different measures. The current results provide new insights into the neural underpinnings of ASD and provide targets for potential interventions using brain modulation and behavioural training.

Feminist scholars have long been concerned with claims of hardwired brain sex differences emanating from neuroscience and evolutionary psychology. Past criticisms of these claims have rightfully questioned the impact of this research on gender equality, pointing out how findings can be used to vindicate gender stereotypes. In this article, we appraise the brain sex differences literature through the lens of open science, a movement aimed at improving the robustness and reliability of science. In this discussion, we offer a feminist evaluation of the strategies (e.g., pre-registration, data sharing, and accountability) provided by open science, and we question whether these may be the novel and disruptive tools needed to dismantle claims about hardwired brain sex differences. We suggest that open science strategies can be useful in challenging some of these claims, and we note that promising initiatives are already being developed in neuroscience and allied fields. We end by acknowledging the distinct challenges that feminist researchers wishing to engage in open science face, particularly in the context of limited diversity. We conclude that open science presents considerable opportunity for feminist researchers, and that it will be crucial for feminists to be involved in shaping the future of this movement.

ImportanceThe neurobiological underpinnings underlying sex differences in cognition during adolescence are largely unknown.ObjectiveTo examine sex differences in brain circuitry and their association with cognitive performance in US children.Design, Setting, and ParticipantsThis cross-sectional study analyzed behavioral and imaging data from 9- to 11-year-old children from the Adolescent Brain Cognitive Development (ABCD) study between August 2017 and November 2018. The ABCD study is an open-science, multisite study following up more than 11 800 youths into early adulthood for 10 years with annual laboratory-based assessments and biennial magnetic resonance imaging (MRI). The selection of ABCD study children for the current analysis was based on the availability of functional and structural MRI data sets in ABCD Brain Imaging Data Structure Community Collection format. Five hundred and sixty participants who had excessive level of head motion (>50% of time points with framewise displacement >0.5 mm) during resting-state functional MRI were excluded from the analyses. Data were analyzed between January and August 2022.Main Outcomes and MeasuresThe main outcomes were the sex differences in (A) global functional connectivity density at rest and (B) mean water diffusivity (MD) and (C) the correlation of these metrics with total cognitive scores.ResultsA total of 8961 children (4604 boys and 4357 girls; mean [SD] age, 9.92 [0.62] years) were included in this analysis. Girls had higher functional connectivity density in default mode network hubs than boys, predominantly in the posterior cingulate cortex (Cohen d = −0.36), and lower MD and transverse diffusivity, predominantly in the superior corticostriatal white matter bundle (Cohen d = 0.3). Age-corrected fluid and total composite scores were higher for girls than for boys (Cohen d = −0.08 [fluid] and −0.04 [total]; P = 2.7 × 10−5). Although total mean (SD) brain volume (1260 [104] mL in boys and 1160 [95] mL in girls; t = 50; Cohen d = 1.0; df = 8738) and the proportion of white matter (d = 0.4) were larger for boys than for girls, the proportion of gray matter was larger for girls than for boys (d = −0.3; P = 2.2 × 10−16).Conclusions and RelevanceThe findings of this cross-sectional study on sex differences in brain connectivity and cognition are relevant to the future creation of brain developmental trajectory charts to monitor for deviations associated with impairments in cognition or behavior, including those due to psychiatric or neurological disorders. They could also serve as a framework for studies investigating the differential contribution of biological vs social or cultural factors in the neurodevelopmental trajectories of girls and boys.