than that of cisgender men. It also reports that gynephilic trans women differ from both cisgender female and male controls in non-dimorphic brain areas. Cortical thickness, which is generally thicker in cisgender women's brains than in cisgender men's brains, may also be thicker in trans women's brains, but is present in a different location to cisgender women's brains. For trans men, research indicates that those with early-onset gender dysphoria and who are gynephilic have brains that generally correspond to their assigned sex, but that they have their own phenotype with respect to cortical thickness, subcortical structures, and white matter microstructure, especially in the right hemisphere. Hormone therapy can also affect transgender people's brain structure; it can cause transgender women's brains to become closer to those of cisgender women, and morphological changes observed in the brains of trans men might be due to the anabolic effects of testosterone. While MRI taken on gynephilic trans women have likewise shown differences in the brain from non-trans people, no feminization of the brain's structure has been identified. Neuroscientists Ivanka Savic and Stefan Arver at the Karolinska Institute used MRI to compare 24 gynephilic trans women with 24 cisgender female and 24 cisgender male controls. None of the study participants were undergoing hormone therapy. The researchers found sex-typical differentiation between the trans women and cisgender females, and the cisgender males; but the gynephilic trans women "displayed also singular features and differed from both control groups by having reduced thalamus and putamen volumes and elevated GM volumes in the right insular and inferior frontal cortex and an area covering the right angular gyrus". The researchers concluded that:Berglund et al. (2008) tested the response of gynephilic trans women to two steroids hypothesized to be sex pheromones: the progestin-like 4,16-androstadien-3-one (AND) and the estrogen-like 1,3,5(10),16-tetraen-3-ol (EST). Despite the difference in sexual orientation, the trans women's hypothalamic networks activated in response to the AND pheromone, like the androphilic cis female control groups. Both groups experienced amygdala activation in response to EST. Gynephilic cis male control groups experienced hypothalamic activation in response to EST. However, the trans women also experienced limited hypothalamic activation to EST. The researchers concluded that in terms of pheromone activation, trans women occupy an intermediate position with predominantly female features. The transfeminine subjects had not undergone any hormonal treatment at the time of the study, according to their own declaration beforehand, and confirmed by repeated tests