Neural substrates of sexual arousal are not sex dependent

Abstract

Sexual arousal is a dynamical, highly coordinated neurophysiological process that is often induced by visual stimuli. Numerous studies have proposed that the cognitive processing stage of responding to sexual stimuli is the first stage, in which sex differences occur, and the divergence between men and women has been attributed to differences in the concerted activity of neural networks. The present comprehensive metaanalysis challenges this hypothesis and provides robust quantitative evidence that the neuronal circuitries activated by visual sexual stimuli are independent of biological sex. Sixty-one functional magnetic resonance imaging studies (1,850 individuals) that presented erotic visual stimuli to men and women of different sexual orientation were identified. Coordinate-based activation likelihood estimation was used to conduct metaanalyses. Sensitivity and clustering analyses of averaged neuronal response patterns were performed to investigate robustness of the findings. In contrast to neutral stimuli, sexual pictures and videos induce significant activations in brain regions, including insula, middle occipital, anterior cingulate and fusiform gyrus, amygdala, striatum, pulvinar, and substantia nigra. Cluster analysis suggests stimulus type as the most, and biological sex as the least, predictor for classification. Contrast analysis further shows no significant sex-specific differences within groups. Systematic review of sex differences in gray matter volume of brain regions associated with sexual arousal (3,723 adults) did not show any causal relationship between structural features and functional response to visual sexual stimuli. The neural basis of sexual arousal in humans is associated with sexual orientation yet, contrary to the widely accepted view, is not different between women and men.

No basal or drug‐induced sex differences in striatal dopaminergic levels: a cluster and meta‐analysis of rat microdialysis studies

“…Thereby, the spatiotemporal scale of consideration and context are critical. While functional systems level studies question the presence of sexual dimorphisms within reward circuitry with respect to sexual arousal (Mitricheva, et al, ; Stark, et al, ), cellular and molecular sex differences associated with addiction may still be present within the same network (Sanchis‐Segura and Becker, ; Huber, et al, ; Becker and Chartoff, ). In addition to context and scales of consideration, the proper sample size, choice of statistical methods and data convergence may further influence the outcome of investigations and thus, conclusions made on sex differences.…”

Women at Greater Sexual Risk for STIs/HIV Have a Lower Mesolimbic and Affective Bias Response to Sexual Stimuli

“…biases) are more favorable for women whose partners use condoms. While some studies have reported male vs. female differences of neurobiological and behavioral responses to sexual stimuli (Rupp and Wallen, 2008;Hill et al, 2011), a recent meta-analysis found that females and males generally activate the same brain regions in response to sexual cues (Mitricheva et al, 2019). In addition, while a recent study found that differential patterns in the subcortical response to non-sexual cues between males vs. females were predictive of sexual risk behaviors (Victor et al, 2015), it is unclear whether there would be differences in the mesolimbic response to sexual cues between males vs. females with varying degrees of STIs/HIV sexual risk behaviors.…”

“…Significant nodes within the cue-reactive mask (e.g., dorsal striatum, insula) that differed between the Protected and Unprotected groups have been shown to be involved in the processing of visual sexual stimuli (Mitricheva et al, 2019). The caudate and putamen process both positive and negative stimuli (Lammel et al, 2014), driving reward-seeking behaviors and motivational states (Wise, 2004), such as pleasurable eating (e.g., Small et al, 2003), drug craving (e.g., Breiter et al, 1997;Wong et al, 2006;Volkow et al, 2006), sexual-related activities (see review, Gola and Draps, 2018), and the pursuit and loss of monetary value (e.g., Knutson et al, 2000).…”

“…Unprotected). Primary analyses were limited to subcortical regions [e.g., caudate, putamen, insula, amygdala, hippocampus, caudal orbitofrontal cortex (e.g., ventrolateral prefrontal cortex, or vlPFC), thalamus] associated with neural responses to sexual stimuli (Mitricheva et al, 2019) and other evocative cues (Childress et al, 1999;Franklin 1 http://www.fil.ion.ucl.ac.uk/spm Noori et al, 2016;Regier et al, 2017). These regions were combined into a mesolimbic ''cue-reactive'' mask ( Figure 1) using the Harvard-Oxford probabilistic anatomical atlas included with FMRIB Software Library (FSL).…”

Analyzing brain data by sex: Are we asking the right question?

“…Thus, on the basis of a review of studies of sex differences in human brain structure, Eliot concluded that when brain size is controlled for, sex category accounts for less than 2% of the variability in brain structure ( 19 ). Recent studies, which assessed the contribution of several factors to variability in brain function (measured using functional MRI), reported that sex category explained only a small fraction of this variability ( 20, 21 ). Finally, an assessment of the relations between the number of sex differences in functional MRI studies and sample size did not reveal the positive correlation expected if brain function of women and men belonged to two populations ( 22 ).…”