Integrating Neural Circuits Controlling Female Sexual Behavior

Abstract

The hypothalamus is most often associated with innate behaviors such as is hunger, thirst and sex. While the expression of these behaviors important for survival of the individual or the species is nested within the hypothalamus, the desire (i.e., motivation) for them is centered within the mesolimbic reward circuitry. In this review, we will use female sexual behavior as a model to examine the interaction of these circuits. We will examine the evidence for a hypothalamic circuit that regulates consummatory aspects of reproductive behavior, i.e., lordosis behavior, a measure of sexual receptivity that involves estradiol membrane-initiated signaling in the arcuate nucleus (ARH), activating β-endorphin projections to the medial preoptic nucleus (MPN), which in turn modulate ventromedial hypothalamic nucleus (VMH) activity—the common output from the hypothalamus. Estradiol modulates not only a series of neuropeptides, transmitters and receptors but induces dendritic spines that are for estrogenic induction of lordosis behavior. Simultaneously, in the nucleus accumbens of the mesolimbic system, the mating experience produces long term changes in dopamine signaling and structure. Sexual experience sensitizes the response of nucleus accumbens neurons to dopamine signaling through the induction of a long lasting early immediate gene. While estrogen alone increases spines in the ARH, sexual experience increases dendritic spine density in the nucleus accumbens. These two circuits appear to converge onto the medial preoptic area where there is a reciprocal influence of motivational circuits on consummatory behavior and vice versa. While it has not been formally demonstrated in the human, such circuitry is generally highly conserved and thus, understanding the anatomy, neurochemistry and physiology can provide useful insight into the motivation for sexual behavior and other innate behaviors in humans.

Dopamine and addiction: what have we learned from 40 years of research

“…Importantly, DA does not appear indispensable to drive feeding but it is necessary to motivate animals to exert an effort to obtain food (Salamone et al 2007) and it appears to be sensitive to the novelty and the palatability of food (Di Chiara and Bassareo 2007). Finally, DA has been shown to be central for sexual reward and in particularly for its appetitive aspects (Damsma et al 1992;Everitt 1990;Fibiger et al 1992;Micevych and Meisel 2017).…”

Estrus-Cycle Regulation of Cortical Inhibition

“…In humans, generalized changes in brain function include alterations of sensory processing [5], cognitive function [6], and the periodic occurrence of epilepsy [7,8] during the menstrual cycle. While cyclical changes have been studied in detail in subcortical structures [9,10], relatively little is known about how the estrus cycle affects cortical processing.…”

Selective sexual differentiation of neurone populations may contribute to sex‐specific outputs of the ventromedial nucleus of the hypothalamus

“…Subsets of VMHvl neurones contribute to the circuitry underlying female sexual receptivity and male‐pattern mating behaviour. In females, the VMH is the final integration site for the hypothalamic and limbic circuits that underlie the expression of lordosis . Female rodents are sexually receptive at specific times in their oestrus cycle, starting with the evening of pro‐oestrus and ending with the morning of oestrus, in a manner that is dependent on oestradiol and progesterone .…”