Article Title: Neural Bases of Hypoactive Sexual Desire Disorder in Women: An Event-Related fMRI Study
Originally Published: June 2011
"As expected, behavioral results showed that NHSDD [no hypoactive sexual desire disorder] participants rated erotic stimuli significantly higher than HSDD [hypoactive sexual desire disorder] participants did on a 10-point desirable scale. No rating difference was observed for the non-erotic stimuli between NHSDD and HSDD participants. Our functional neuroimaging results extended these data by demonstrating two distinct types of neural changes in participants with and without HSDD. In comparison with HSDD participants, participants without HSDD demonstrated more activation in brain areas involved in the processing of erotic stimuli...Interestingly, HSDD participants also showed additional activations in brain areas associated with higher order social and cognitive functions...
"Together, these findings indicate that HSDD participants do not only show a hypo [less] activation in brain areas mediating sexual desire, but also a different brain network of hyper [increased] activation, which might reflect differences in subjective, social, and cognitive interpretations of erotic stimuli. "
Article Title: Physiology of Women's Sexual Function: Basic Knowledge and New Findings
Originally Published: July 2010
"Importantly, the study by Maravilla and Yang demonstrated decreased activation in bilateral temporal lobe with the VSS [visual sexual stimulation] arousal stimulus, at sites that have been associated with moral judgment or embarrassment. This led to hypothesize that such a decreased activity was due to lowering of activity in sites that normally exhibit active inhibition to a sexual stimulus. A possible inhibitory influence of the temporal cortex over sexual arousal in women has been also recently confirmed, with a peculiar greater activation of the entorhinal cortex (part of the temporal cortex) in women with hyposexual desire as compared with healthy heterosexual women, when watching VSS stimuli.
"Relative to the nonsexual resting state, Georgiadis et al. reported that rCBF [regional Cerebal Blood Flow] decreases in the inferomedial temporal lobe—including the amygdala—during clitoral stimulation and during orgasm. Activity levels in the left parahippocampal gyrus and anterior temporal pole decreased even further from clitoral stimulation to orgasm. As stated above, temporal lobe probably exerts a tonic inhibition on sexual arousal, and a successful release of this inhibition may be imperative in the event of sexual opportunity. This was confirmed by a highly significant inverse relationship between PSA [Perceived Sexual Arousal] ratings and temporal lobe blood flow. Clinical findings of temporal lobe lesions causing hypersexuality, and temporal lobe epilepsy-associated sexual (or even orgasmic) auras provide further support.
"Georgiadis et al. suggested that the activity level of the OFC [orbitofrontal cortex] reflects conscious control over the sexual urge: high control during clitoral stimulation (because orgasm was not allowed), with increased rCBF, and decreased rCBF during orgasm, thus indicating the release of that conscious control. The failed orgasm attempts, too, were associated with increased rCBF in the OFC, providing strong evidence that OFC activity levels significantly determine sexual behavioral outcome. Possibly, the loss of conscious control and the release of tension that people report when they describe an orgasmic experience relates to this decreased OFC activity.
"The authors concluded that the increase in activation in the medial frontal and the right inferior frontal gyri suggested that the HSDD [hypoactive sexual desire disorder] group was directing more of their attention to self-evaluation of their responses which may have been distracting and interfered with the normal sexual arousal response. Even more interestingly, this study also compared simultaneous VPP with the fMRI and found no between-group differences in VPP–fMRI correlated activation, nor was VPP correlated with subjective arousal response."
Article Title: Women with hypoactive sexual desire disorder compared to normal females: a functional magnetic resonance imaging study.
Originally Published: January 2009
"Lack of sexual interest is the most common sexual complaint among women. However, factors affecting sexual desire in women have rarely been studied. While the role of the brain in integrating the sensory, attentional, motivational, and motor aspects of sexual response is commonly acknowledged as important, little is known about specific patterns of brain activation and sexual interest or response, particularly among women...The results suggest differences between women with NHSD [no history of sexual dysfunction] and HSDD [hypoactive sexual desire disorder] in encoding arousing stimuli, retrieval of past erotic experiences, or both. The findings of greater activation in BA 10 and BA 47 among women with HSDD suggest that this group allocated significantly more attention to monitoring and/or evaluating their responses than NHSD participants, which may interfere with normal sexual response."