Brain’s Neural connectivity shapes musical ­rhythm sense

Non­-musicians could process rhythm as well as trained musicians

A sense of rhythm, integral to musicianship, may be as highly developed even in those with minimal or no training in music and may in large part be due to dense neural connections in specific regions of the brain, says a study by scientists at the National Brain Research Centre (NBRC), Manesar, and Symbiosis International, Pune. How much of musical ability is inherent, the extent to which it is influenced by training and the regions of the brain that are most activated while perceiving musical elements such as rhythm and pitch are vibrant areas of research. Studies have shown, for instance, that at least 15 months of musical training in early childhood led to long­ term changes in the brain’s structure that diverged from typical brain development.

Other studies have shown that the brain’s neuroanatomy plays a significant role, and yet others have even linked certain genes. For instance the gene (GATA2) that regulates the development of cochlear hair cells and the structures that mediate sound perception in the auditory pathway have been associated with individual differences in music processing and perception.

Key question

For Nandini Chatterjee Singh, a neuroscientist who leads the Language Literacy and Music Laboratory lab at NBRC, the question was whether the connectivity in the brain and certain brain structures were either minimal or absent in non­-musicians and whether progressively higher musical training influenced the density or degree of connectivity among certain brain regions.

Profiling musical skills

To test this, she and collaborators Archith Rajan, Apurva Shah and Madhura Ingalhalikar recruited 27 university graduates — 13 female — with varying degrees of musical training ranging from non-musicians to professionals and assessed them on a test called Profile of Music Perception skills. This standardised computer­ based test, since 2012, has been used in used in research to test the listener’s abilities at discerning changes in rhythm, pitch, accent and melody. Their scores were evaluated along with brain imaging data from all of the participants.
“What we found was that non musicians performed as well as trained musicians on rhythm processing tasks because of the way the brain is connected. So there are hidden — or sleeping musicians — among us,” Singh told The Hindu, “But this was only specific to rhythm and we didn’t find any strong patterns in the perception of pitch.” Rather than connections within the right and left hemispheres of the brain it was the strength of connections between the two hemispheres of the brain that significantly influenced rhythmic processing abilities. The density of connection in the right posterior cingulate cortex, a region that acted as hub of connectivity between the two halves of the brain was strongly linked to participants’ overall scores. The study has been accepted for publication in the peer-­re-viewed European Journal of Neuroscience.

Significance of rhythm

That the perception of rhythm was so strongly stamped in the brain underlined its significance to language processing as well opened lines of enquiry into several areas of research including into autism, musical aptitude as well the use of music therapy for a variety of physiotherapy and rehabilitation exercises, Singh added.

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