It is the question that has baffled and intrigued people for centuries: why do orgasms feel so good?

That is the crux of a new study that breaks down what happens to our bodies when we reach the height of sexual stimulation.

Despite centuries of research, scientists remain somewhat ignorant about the underlying mechanisms of a climax.

But now neuroscientist Adam Safron, of Northwestern University, has mapped out how rhythmic stimulation alters brain activity.

In a nutshell, sexual stimulation focuses our neurons in such a way that we are sent into a trance, blocking out everything else and concentrating solely, intensely on the sensation alone.

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Sexual stimulation re-routes brain activity, sending us into an altered state of consciousness

We lose our usual self-awareness and consciousness of other noises, feelings, and smells around us.

No other natural stimulation could recreate this level of concentration.

'Sex is a source of pleasurable sensations and emotional connection, but beyond that, it's actually an altered state of consciousness,' Dr Safron explains.

To examine this unique trance, Dr Safron reviewed related studies and literature over many years to come up with a model in which rhythmic sexual activity likely influences brain rhythms.

His model showed stimulating particular nerves in a particular way at a particular speed over and over again focuses our neurons.

They begin to synchronize their activity. This focusing process is called neural entrainment.

Eventually, if stimulation continues long enough, this synchronization can spread throughout the brain making us more focused than ever.

This may be crucial for allowing for a sufficient intensity of experience to trigger the mechanisms of climax.

Dr Safron's previous research has focused on the neural bases of sexual preferences.

He said orgasm is related to this work because it is one of the most powerful rewards available, and therefore, may have an important role in shaping preferences.

'Before this paper, we knew what lit up in the brain when people had orgasms, and we knew a lot about the hormonal and neurochemical factors in non-human animals, but we didn't really know why sex and orgasm feel the way they do,' Dr Safron said.

'This paper provides a level of mechanistic detail that was previously lacking.'

WHY RHYTHM IS SO IMPORTANT

To Dr Safron's surprise, he found parallels between sexual climax, seizures, music and dance.

All four flood the brain's sensory channels with rhythmic inputs.

'Synchronization is important for signal propagation in the brain, because neurons are more likely to fire if they are stimulated multiple times within a narrow window of time,' Dr Safron said.

'Otherwise, the signals decay as part of a general resetting mechanism, rather than sum together.

'This then caused me to hypothesize that rhythmic entrainment is the primary mechanism by which orgasmic thresholds are surpassed.'

Dr Safron said this research could be relevant for improving sexual functioning, encouraging people to focus more on the rhythmic aspects of sexuality.

'The idea that sexual experiences can be like trance states is in some ways ancient. Turns out this idea is supported by modern understandings of neuroscience,' Dr Safron said.

'In theory, this could change the way people view their sexuality.

'And although obvious in retrospect, I wasn't expecting to find that sexual activity was so similar to music and dance, not just in the nature of the experiences, but also in that evolutionarily, rhythm-keeping ability may serve as a test of fitness for potential mates.'