The Science of Love: How The Brain Controls Physical Reactions to Intimacy

Led by Professor Julie Bakker at Liège University (Belgium) and Professor Ulrich Boehm at Saarland University (Germany), there has been a major advancement in our understanding of how the brain controls physical response to intimacy and this was published in Nature Communications. They found that a hormone in the brain, called kisspeptin, drives both attractions to the opposite sex and sexual behavior.

The scientists found that a male mouse secretes pheromones to activate the kisspeptin neurons which send this signal along to other neurons, releasing the gonadotropin hormones that control attraction to the opposite sex.

Neuroimaging techniques have begun to be applied to the study of human sexual behavior.

According to Boehm, "This work has provided new insight into how the brain decodes signals from the outside world and then translates these environmental cues into behavior."

Testing female rodents, mate preference and copulatory behavior depend on pheromones and are synchronized with ovulation to ensure reproductive success. The neural circuits driving this orchestration in the brain have, however, remained ambiguous.

Boehm added that little was known about how the brain ties together ovulation, attraction, and sex, but now we acknowledge kisspeptin that controls all of these aspects through different brain circuits running in parallel with one another.

In conclusion, puberty, fertility, attraction, and sex are all controlled by a single molecule; kisspeptin.

In another study, deep brain imaging techniques were used to analyze the brains of mice, including optogenetics which uses light to stimulate particular parts of the brain. They traced the trigger of attraction to the hypothalamus, an evolutionarily ancient structure at the bottom-center of the brain that is responsible for controlling major bodily functions such as body temperature, hunger, thirst, and sexual behavior.

The researchers at the University of North Carolina (UNC) School of Medicine examined the medial preoptic area (mPOA) of the brain -- a specific set of neurons inside the hypothalamus -- because previous research found the mPOA was important for social and reproductive behavior in all vertebrate species studied from fish to human.

By exposing female mice to male mouse urine, a large number of the neurons in the mPOA became excited into greater activity.

However, human sexuality does not rely on a single "sex nucleus," but it involves many -- sometimes quite generic -- brain functions including those for arousal, reward, memory, cognition, self-referential thinking, and social behavior.

People tend to feel bolder and less inhibited during sex because the part of your brain in charge of your logical reasoning skills temporarily takes a rest.

Our brains control all steps of sexual behavior and in all its variations, from feelings of sexual desire and partner choice to arousal, orgasm and even post-coital cuddling.

The brains of males and females are different and work differently when it comes to sexual activity.

The orchestration between our sensory systems (vision, hearing, taste, smell, and touch), the endocrine/hormonal system, and the autonomic nervous system result in sexual drive and desire.

Researchers use fMRI (Functional Magnetic Resonance Imaging) Machines or a PET (Positron Emission Tomography) scans to measure the blood flow and neuron activity in the brain.

Results from these findings are finally being integrated for meta-analysis, allowing for improved precision in identifying activated brain areas.