Association of Cerebral Networks in Resting State with Sexual Preference of Homosexual Men: A Study of Regional Homogeneity and Functional Connectivity

Abstract

Recent imaging studies have shown that brain morphology and neural activity during sexual arousal differ between homosexual and heterosexual men. However, functional differences in neural networks at the resting state is unknown. The study is to characterize the association of homosexual preference with measures of regional homogeneity and functional connectivity in the resting state. Participants were 26 healthy homosexual men and 26 age-matched healthy heterosexual men in whom we collected echo planar magnetic resonance imaging data in the resting state. The sexual orientation was evaluated using the Kinsey Scale. We first assessed group differences in regional homogeneity and then, taking the identified differences as seed regions, we compared groups in measures of functional connectivity from those seeds. The behavioral significances of the differences in regional homogeneity and functional connectivity were assessed by examining their associations with Kinsey Scores. Homosexual participants showed significantly reduced regional homogeneity in the left inferior occipital gyrus, right middle occipital gyrus, right superior occipital gyrus, left cuneus, right precuneus, and increased regional homogeneity in rectal gyrus, bilateral midbrain, and left temporal lobe. Regional homogeneity correlated positively with Kinsey scores in the left inferior occipital gyrus. The homosexual group also showed reduced functional connectivity between left middle temporal gyrus, left supra-marginal gyrus, right cuneus and the seed region, i.e. left inferior occipital gyrus. Additionly, the connection between the left inferior occipital gyrus and right thalamus correlated positively with Kinsey scores. These differences in regional homogeneity and functional connectivity may contribute to a better understanding of the neural basis of male sexual orientation.

Gender effects and sexual-orientation impact on androstadienone-evoked behavior and neural processing

“…Recently, behavioral and neuroimaging results from Perry et al (2013) showed empathy to be related to gender, as well as sexual preference. Further, a study aiming to characterize regional homogeneity and functional connectivity during rest found significant differences between homo- and heterosexual men (Hu et al, 2013). Hence, it would be presumptuous not to consider the ability to use this variable as a modulating factor to achieve homogeneous subject groups.…”

Cerebral sex dimorphism and sexual orientation

“…While congruently suggesting a less pronounced or even sex‐reversed differentiation of cerebral midline structures, most previous studies were limited to a specific cerebral area (exceptions are Hu et al, , Abe et al, 2014) and a single metric; moreover, several of the studies only included male controls. Consequently, important facets of the possible neurobiology of sexual orientation remain unrevealed.…”

“…Zhou et al subsequently also found that smelling a putative male pheromone enhanced the visual perception of male figures among HoM and HeF, but not among HeM, indicating that hypothalamic activation in HoM and HeF had downstream effects on visual perception, potentially impacting sexual partner selection (Berglund, Lindstrom, Dhejne‐Helmy, & Savic, ; Berglund, Lindstrom, & Savic, ; Zhou et al, ). More recently, Hu et al () used MRI to measure homogeneity in resting‐state brain activity (presumably reflecting local functional connections), and found that HoM had greater homogeneity in the mid frontal lobe and lesser homogeneity in the middle and inferior occipital lobe compared to HeM.…”

Differing Default Mode Network Activities in Men with Homosexual or Heterosexual Preferences

“…These differences in the fALFF and FC suggest male sexual preference may influence the pattern of activity in the DMN. Although our previous study had shown differences between heterosexual and homosexual men in the ReHo and FC [13], the present study focused on the fALFF, which is a notably different analytical approach. Additionally, we should emphasize that the seeds and results of the FC analysis in the present study differed entirely from our previous investigation.…”

“…Using the left inferior occipital gyrus as the seeding area, homosexual men showed decreased FC in the left middle temporal gyrus, left supra‐marginal gyrus, left inferior occipital gyrus, and right cuneus. Additionally, FCs in the right thalamus and right cuneus correlated positively with a homosexual preference [13].…”