Brain Connectivity Dynamics in Untreated Transmen and Cisgender Individuals

Abstract

Large-scale brain network interactions have been described between trans- and cis-gender identities. However, a temporal perspective of the brain spontaneous fluctuations is missing. We investigated the functional connectivity dynamics in transmen with gender incongruence and its relationship with interoceptive awareness. We describe four states in native and meta-state spaces: i) one state highly prevalent with sparse overall connections; ii) a second with strong couplings mainly involving components of the salience, default and executive control networks. Two states with global sparse connectivity but positive couplings iii) within the sensorimotor network, and iv) between salience network regions. Transmen had more dynamical fluidity than cismen, while cismen presented less meta-state fluidity and range dynamism than transmen and ciswomen. A positive association between attention regulation and fluidity, and meta-state range dynamism was found in transmen. There exist gender differences in the temporal brain dynamism, characterized by distinct interrelations of the salience network as catalyst interacting with other networks. We provide a functional explanation to the neurodevelopmental hypothesis proposing different brain phenotypes in the construction of the gendered-self.