Activation of neural pathways associated with sexual arousal in non‐human primates

Abstract

Purpose: To evaluate brain activity associated with sexual arousal, fully conscious male marmoset monkeys were imaged during presentation of odors that naturally elicit high levels of sexual activity and sexual motivation. Material and Methods:Male monkeys were lightly anesthetized, secured in a head and body restrainer with a built-in birdcage resonator and positioned in a 9.4-Tesla spectrometer. When fully conscious, monkeys were presented with the odors of a novel receptive female or an ovariectomized monkey. Both odors were presented during an imaging trial and the presentation of odors was counterbalanced. Significant changes in both positive and negative BOLD signal were mapped and averaged.Results: Periovulatory odors significantly increased positive BOLD signal in several cortical areas: the striatum, hippocampus, septum, periaqueductal gray, and cerebellum, in comparison with odors from ovariectomized monkeys. Conversely, negative BOLD signal was significantly increased in the temporal cortex, cingulate cortex, putamen, hippocampus, substantia nigra, medial preoptic area, and cerebellum with presentation of odors from ovariectomized marmosets as compared to periovulatory odors. A common neural circuit comprising the temporal and cingulate cortices, putamen, hippocampus, medial preoptic area, and cerebellum shared both the positive BOLD response to periovulatory odors and the negative BOLD response to odors of ovariectomized females. Conclusion:These data suggest the odor-driven enhancement and suppression of sexual arousal affect neuronal activity in many of the same general brain areas. These areas included not only those associated with sexual activity, but also areas involved in emotional processing and reward.

Linking nucleus accumbens dopamine and blood oxygenation

“…Critical research establishing generalization of phMRI findings to shorter timescales has yet to be conducted. For instance, future experiments might combine dopamine depletion or antagonism with stimuli known to elicit fast increases in NAcc BOLD signal (e.g., sexually arousing odors in animals or monetary cues in humans; Ferris et al 2004;Knutson et al 2001;Leyton et al 2004). If fast increases in NAcc BOLD signal depend upon postsynaptic D1 agonism (and not, for instance, glutamate release), they should be blunted by dopamine depletion or antagonism.…”

Reward processing by the dorsal raphe nucleus: 5-HT and beyond

“…The recreational drug MDMA strongly activates the DRN in awake monkeys (Brevard et al 2006). Other fMRI imagings report DRN activation by social behaviors and social signals (Ferris et al 2004;Acevedo et al 2012). However, the neural responses of the DRN are negatively covaried with the responses of the nucleus accumbens to the magnitude of omitted rewards (Pedroni et al 2011).…”

MRI Techniques and New Animal Models for Imaging the Brain

“…For example, the BOLD signal of conscious nonhuman primate males exposed to the scent of peri-ovulatory females is greater than when exposed to the scent of ovariectomized females in various hypothalamic (Ferris et al 2001; see above Fig. 4) and cortical areas (Ferris et al 2004). With regard to the formation of a maternal bond in the rat, it has been shown that suckling activates similar brain areas to those activated by a central injection of oxytocin (Febo et al 2005), a neuropeptide involved in social attachment (Young et al 2008) and maternal behaviour (Levy et al 2004).…”