Desire, and the brain that generates it

In men with low sexual desire, kisspeptin changed activity in the brain networks that process sexual and emotional cues, and penile responses followed. This is desire at the level of the wiring that generates wanting, not blood flow at the destination. It places kisspeptin alongside the melanocortin molecules as a central rather than a vascular answer to low desire, and it reaches it through a hormone pathway rather than an arousal pathway.