Considering that sexual reproduction is the driving force behind genetic diversity and evolutionary changes, it should be no shock that our sexual drives are some of the most compelling bodily drives we interface with. For this reason, it should be no surprise that the sexual nature of humans and animals has always been of the utmost interest to researchers. Today, we are going to break down sexual function from a neurological perspective.
In humans, sexual behavior is said to occur cyclically in 4 phases: libido, arousal, orgasm, and resolution. During the libido phase, the strong desire for sexual activity begins. Environmental and internal stimuli are determined to be sexually relevant by limbic structures, important for emotional processing and behaviors, within the brain. These areas then send information to the frontal areas of the brain and the brainstem to bring these stimuli to conscious awareness, while also sending down neuronal projections to your organs to initiate a sexual response through the release of norepinephrine, acetylcholine, and serotonin. This sexual response begins the arousal stage. At this point, heart rate will increase, muscles will tense up, and blood will rush to the genitals. The orgasm phase occurs when the sexual arousal and stimulation hits its climax. At this point there is increased activity of the sympathetic nervous system (the part of your nervous system responsible for fight-or-flight) leading to serotonin release and subsequent muscle contractions. Simultaneously, dopamine floods the reward system. After the orgasm stage comes the resolution stage. This is when our bodies return to their natural states of functioning. It is at this point that natural opioids are released to reduce sexual functioning and arousal during a refractory period (Calabró et al., 2019; Castro, 2014; Cleveland Clinic, 2021; Coria-Avila et al., 2016; Kruger et al., 2020; Pfaus, 1999).
As you can see, proper sexual function requires a symphony of different brain structures and peripheral nerves, working in concert with each other toward promoting and reinforcing reproduction!