Scientists locate the brain circuit that drives male libido

Amazing stuff!

"“We’ve singled out a circuit in male mammals’ brains that controls sexual recognition, libido, and mating behavior and pleasure,” ...

In the latest study, the team focused on a set of BNST neurons that secrete a slow-acting peptide called Substance P. By stimulating this tract, the circuit reached preoptic hypothalamus neurons with receptors for Substance P, which then initiated the male mating behaviors. When the scientists directly stimulated the Substance P neurons in the pre optic hypothalamus, the male mice that had just completed mating behaviors were driven to immediately resume sexual activity.

It showed that the normal refractory period, in which sex drive and mating capabilities are restored after ejaculation, was completely overwritten. Nearly all mammals require this refractory period to physiologically regroup for sexual activity. ... And on the flip side, suppressing this neural activity can completely erode the male’s libido. ..."

"... For the mice used in this study, the normal refractory period is five days. But directly stimulating just the Substance P receptor-containing neurons of the preoptic hypothalamus via experimental manipulations prompted male mice that had just ejaculated to immediately reprise their sexual mating routine all the way to a second consummation in the presence of a female mouse. ...

The study’s findings could lead to drugs that serve as libidinal rheostats, capable of tamping down sex circuitry in the brains of men with hyperactive sex drives, or, alternatively, boosting sex drive in men who suffer from a lack of desire. ..."

From the highlights and abstract:

"Highlights

• A multisynaptic neural circuit that converts sensory input to male sexual behavior

• An embedded molecular timer delays mating onset following mate recognition

• This neural circuit elicits dopamine release and governs male sexual drive and reward

• This neural circuit governs libido and motor displays of male sexual behavior

Summary

Male sexual behavior is innate and rewarding. Despite its centrality to reproduction, a molecularly specified neural circuit governing innate male sexual behavior and reward remains to be characterized. We have discovered a developmentally wired neural circuit necessary and sufficient for male mating. This circuit connects chemosensory input to BNSTprTac1 neurons, which innervate POATacr1 neurons that project to centers regulating motor output and reward. Epistasis studies demonstrate that BNSTprTac1 neurons are upstream of POATacr1 neurons, and BNSTprTac1-released substance P following mate recognition potentiates activation of POATacr1 neurons through Tacr1 to initiate mating. Experimental activation of POATacr1 neurons triggers mating, even in sexually satiated males, and it is rewarding, eliciting dopamine release and self-stimulation of these cells. Together, we have uncovered a neural circuit that governs the key aspects of innate male sexual behavior: motor displays, drive, and reward."

Sexy mice help scientists uncover the drivers behind male libido Scientists say they've uncovered the neural circuitry behind desire that is responsible for sex drive, behavior and reward.

Stanford Medicine scientists locate key brain circuit containing the seat of male libido A team of Stanford Medicine researchers have shown in male mice that a particular neuronal circuit is responsible for sexual arousal and for the actions and pleasure that ensue, opening avenues for treatment in men.

A neural circuit for male sexual behavior and reward (open access)

Graphical abstract

In this image of a male mouse's brain, pink denotes the bed nucleus of the stria terminalis (BNST); green, the preoptic hypothalamus. The impulse flows from pink to green in the neural circuit governing mating drive, behavior and satisfaction.