Sex Differences Along the Autism Continuum: A Twin Study of Brain Structure

On average, men and women differ in brain structure and behaviour, raising the possibility of a link between sex differences in brain and behaviour. But women and men are also subject to different societal and cultural norms. We navigated this challenge by investigating variability of sex-differentiated brain structure within each sex. Using data from the Queensland Twin IMaging study (N=1,040) and Human Connectome Project (N=1,113), we obtained data-driven measures of individual differences along a male-female dimension for brain and behaviour based on average sex differences in brain structure and behaviour, respectively. We found a weak association between these brain and behavioural differences, driven by brain size. These brain and behavioural differences were moderately heritable. Our findings suggest that behavioural sex differences are to some extent related to sex differences in brain structure, but that this is mainly driven by differences in brain size, and causality should be interpreted cautiously.

Download Full-text

Long-term influences of combat exposure and posttraumatic stress symptoms on brain structure, health, and functioning: The Vietnam Era Twin Study of Aging.

Long-term outcomes of military service: The health and well-being of aging veterans. ◽

10.1037/0000061-013 ◽

2018 ◽

pp. 225-243

Author(s):

Carol E. Franz ◽

Michael J. Lyons ◽

William S. Kremen

Keyword(s):

Posttraumatic Stress ◽

Brain Structure ◽

Twin Study ◽

Combat Exposure ◽

Posttraumatic Stress Symptoms ◽

Stress Symptoms ◽

Vietnam Era

Download Full-text

The social brain in female autism: a structural imaging study of twins

Social Cognitive and Affective Neuroscience ◽

10.1093/scan/nsaa064 ◽

2020 ◽

Vol 15 (4) ◽

pp. 423-436

Author(s):

Élodie Cauvet ◽

Annelies van’t Westeinde ◽

Roberto Toro ◽

Ralf Kuja-Halkola ◽

Janina Neufeld ◽

...

Keyword(s):

Sex Differences ◽

Social Cognition ◽

Brain Structure ◽

Imaging Study ◽

Autistic Traits ◽

Brain Regions ◽

Autism Spectrum ◽

Social Brain ◽

Twin Design ◽

The Social

Abstract A female advantage in social cognition (SoC) might contribute to women’s underrepresentation in autism spectrum disorder (ASD). The latter could be underpinned by sex differences in social brain structure. This study investigated the relationship between structural social brain networks and SoC in females and males in relation to ASD and autistic traits in twins. We used a co-twin design in 77 twin pairs (39 female) aged 12.5 to 31.0 years. Twin pairs were discordant or concordant for ASD or autistic traits, discordant or concordant for other neurodevelopmental disorders or concordant for neurotypical development. They underwent structural magnetic resonance imaging and were assessed for SoC using the naturalistic Movie for the Assessment of Social Cognition. Autistic traits predicted reduced SoC capacities predominantly in male twins, despite a comparable extent of autistic traits in each sex, although the association between SoC and autistic traits did not differ significantly between the sexes. Consistently, within-pair associations between SoC and social brain structure revealed that lower SoC ability was associated with increased cortical thickness of several brain regions, particularly in males. Our findings confirm the notion that sex differences in SoC in association with ASD are underpinned by sex differences in brain structure.

Download Full-text