Whole‐brain dynamics differentiate among cisgender and transgender individuals

Abstract

How the brain represents gender identity is largely unknown, but some neural differences have recently been discovered. We used an intrinsic ignition framework to investigate whether there are gender differences in the propagation of neural activity across the whole‐brain and within resting‐state networks. Studying 29 trans men and 17 trans women with gender incongruence, 22 cis women, and 19 cis men, we computed the capability of a given brain area in space to propagate activity to other areas (mean‐ignition), and the variability across time for each brain area (node‐metastability). We found that both measurements differentiated all groups across the whole brain. At the network level, we found that compared to the other groups, cis men showed higher mean‐ignition of the dorsal attention network and node‐metastability of the dorsal and ventral attention, executive control, and temporal parietal networks. We also found higher mean‐ignition values in cis men than in cis women within the executive control network, but higher mean‐ignition in cis women than cis men and trans men for the default mode. Node‐metastability was higher in cis men than cis women in the somatomotor network, while both mean‐ignition and node‐metastability were higher for cis men than trans men in the limbic network. Finally, we computed correlations between these measurements and a body image satisfaction score. Trans men's dissatisfaction as well as cis men's and cis women's satisfaction toward their own body image were distinctively associated with specific networks in each group. Overall, the study of the whole‐brain network dynamical complexity discriminates gender identity groups, functional dynamic approaches could help disentangle the complex nature of the gender dimension in the brain.

CBLL1 is hypomethylated and correlates with cortical thickness in transgender men before gender affirming hormone treatment

“…So, based on the sexual differentiation of the brain, a neurodevelopmental cortical hypothesis was suggested to explain the emergence of these endophenotypes (9). This hypothesis has found further support by recent functional stationary (10) and dynamic (11) fMRI studies, as well as whole-brain dynamic approaches (12), which also documented brain endophenotypes associated with CM and CW and binary transgender people.…”

“…dynamic approaches (12), which also documented brain endophenotypes associated with CM and CW and binary transgender people.…”

CBLL1 is hypomethylated and correlates with cortical thickness in transgender men before gender affirming hormone treatment

“…So, based on the sexual differentiation of the brain, a neurodevelopmental cortical hypothesis was suggested to explain the emergence of these endophenotypes 9 . This hypothesis has found further support by recent functional stationary 10 and dynamic 11 fMRI studies, as well as whole-brain dynamic approaches 12 , which also documented brain endophenotypes associated with CM and CW and binary transgender people.…”

Limitations and Future Directions in Sex, Sexuality, and Gender Diverse Research in Neurology

“…There are some neuroanatomical and neurophysiology studies that compare cisgender and transgender persons, or intersex and endosex people, or heterosexual and nonheterosexual people, and aim to uncover neuropathology that could explain a minoritized status. An example is neuroimaging or postmortem studies to uncover a neuroanatomical basis for sexuality or gender differences 45–51 . Many of these studies are rooted in a pathological view of minorized sex variations, sexual orientations, and gender identities, and study “on” rather than “with” communities.…”

“…An example is neuroimaging or postmortem studies to uncover a neuroanatomical basis for sexuality or gender differences. [45][46][47][48][49][50][51] Many of these studies are rooted in a pathological view of minorized sex variations, sexual orientations, and gender identities, and study "on" rather than "with" communities. Even in the case of some statistical neuroanatomical differences between heterosexual and gay men, for example, such findings have limited practical or clinical use.…”