Rhythm On The Brain, And Why We Cant Stop Dancing

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Music and dancing are far from idle pastimes. They are universal forms of expression and deep rewarding activities that fulfil diverse social functions. Both feature in all the worlds cultures and throughout history.

A common feature of music and dance is rhythmic motion, which is often period with a regular pulse-like beat. But the human capacity for rhythm presents something of a puzzle.

Even though rhythmic coordination seems fundamental to human nature, people vary widely in ability. Some have the machine-like accuracy of Michael Jackson, others are closer to the case of beat-deaf Mathieu.

What are the underlying causes of these individual changes? By looking at the style the brain responds to rhythm, we can begin to understand why many of us cant assistance but to move to a beat.

Sometimes the dancing is infectious .

Power Of Rhythm

Rhythm is a powerful force-out. It can regulate mood, ranging from the provoking effect of pounding war drums to the appeasing effect of gently rocking a newborn. It can even induce altered countries of consciousness, as in spiritual rites and shamanic traditions involving trance.

Rhythm and music can also be used for therapeutic intents in the rehabilitation of conditions characterised by motor impairment, such as stroke and Parkinsons disease.

Even more fundamentally, rhythmic skills displayed in the context of music and dance may have been essential to our evolution as a species.

In The Descent of Man( 1871 ), Charles Darwin mused that 😛 TAGEND

it seems probable that the progenitors of human, either the males or females or both sexualities, before acquiring the power of expressing their reciprocal love in articulated speech, has worked to charm one another with musical notes and rhythm.

We seem naturally equipped to learn how to move to rhythm .

Rhythmically coordinated body movements may function similarly to fuel sexual attraction by providing an honest signal( one that cant be faked) of an individuals health and fitness.

Outside the competitive arena of seeing a mate, coordinating with others through music and dance facilitates social cohesion by promoting interpersonal bonding, trust, and cooperation.

These prosocial effects of music and dance may have contributed to the prospering of human culture by preventing the disintegration of early societies into antisocial mobs.

Today, they remain potent enough to be are dependent upon, even in maximum security prisons.

Entrainment

But if music and dancing are so universal, why are some people simply unable to hold a rhythm?

The key to answering this question lies in how the human brain locks onto rhythm in the external environment, and how this process of neural entrainment supports the coordination of body movements.

Neural entrainment occurs when regular sensory input, like music with a clear beat, triggers periodic bursts of synchronised brain activity. This periodic activity can continue independently of external rhythmic input due to interactions between already excited neurons. It is as if they expect the sensory input to continue.

Entrainment can thus enhance processing of incoming information by allocating neural resources to the right place at the right time. When performing or dancing to music, entrainment allows the timing of upcoming beats to be predicted.

Sometimes we just have to move. Scott Robinson/ Flickr, CC BY

A recent analyze on individual differences in rhythmic skill identified relationships between the strength of neural entrainment and the capacity to synchronise movements with musical rhythms.

We measured entrainment to the underlying beat in two types of rhythm using electroencephalography( EEG ), a technique where electrical signals reflecting neural activity are recorded via electrodes placed on the head.

One rhythm had a regular beat marked by periodically resulting sound onsets. The other was a relatively complex and jazzier syncopated rhythm in which sound onsets were not present on all beats: some were marked by silence.

Results indicated that the strength of neural entrainment was related to people ability to move in synchrony with the beat. Someones with strong neural responses were more accurate at tapping a thumb in time with the beat of the two rhythms.

We also found individual differences in brain responses to the two rhythm. While some individuals proved a large discrepancies between strength of entrainment for the regular rhythm versus the syncopated rhythm, others showed only a small difference.

In other terms: some people required external physical stimulation to perceive the beat, whereas others were able to generate the beat internally.

All cultures around the world and throughout history have participated in dance .

Remarkably, people who were good at internally producing beats also performed well on a synchronisation task that required them to predict tempo changes in musical sequences.

So the capacity for internal beat generation turns out to be a reliable marker of rhythmic ability. This adds new meaning to Miles Davis reported maxim that in music, stillnes is more important than sound”.

But we still dont know why individual differences in the strength of neural entrainment are available in the first place. They may reflect the efficiency of neural responses at early levels of auditory processing, such as brainstem replies. Or the degree of connectivity between higher-level auditory and motor cortical regions.

Another open question is whether rhythmic skills can be boosted by recent advances in neuroscience. Brain stimulation techniques that induce neural synchrony at specific frequencies offer a promising method for enhancing entrainment and thereby improving an individuals capacity for rhythm.

Peter Keller, Professor of Cognitive Science, Western Sydney University

Read more: www.iflscience.com

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