Study Identifies Part Of Brain Responsible For Tone Deafness

Tone deafness (or congenital amusia) is a lifelong disability that prevents otherwise normal-functioning individuals from developing basic musical skills. The study examined the structural neural correlates of tone deafness. Magnetic resonance imaging data from a group of tone deaf people were compared with the images of people with normal musical ability to find out what area of the brain was responsible for this condition and what possible anatomical anomaly could correlate with this "music disorder."

"The results were consistent across samples in highlighting a reduction in white matter concentration in the right inferior frontal gyrus of amusic individuals," explained Dr. Isabelle Peretz of the Université de Montréal. "The data points to the integrity of white matter tracts in right frontal brain areas as being key in acquiring normal musical competence."

"We used a technology called voxel-based morphometry (VBM), which is a computerized and automated procedure that allows one to search throughout the whole brain for structural differences in terms of brain tissue concentration," explained Dr. Krista L. Hyde of the Montreal Neurological Institute at McGill University and the Department of Psychology at the Université de Montréal. "The individuals who participated in the study were considered tone-deaf on the basis of two main criteria: difficulty recognizing familiar tunes without the assistance of lyrics, and the inability to detect when they are singing out of tune."

The present study constitutes the first investigation into the structural neural correlates of tone deafness. The results have implications for the understanding of normal acquisition of musical abilities and for the diagnosis and remediation of this music-specific disorder.

The study was supported by funds from the Fonds de recherche en santé du Québec and Centre for Interdisciplinary Research in Music Media and Technology to Krista L. Hyde, by funds from Canadian Institutes of Health Research to Isabelle Peretz, and by funds from the Wellcome Trust (UK) to Timothy D. Griffiths.

This research also stems from the International Laboratory for Brain, Music and Sound Research, or BRAMS, which is a collaboration between the Université de Montréal, the Montreal Neurological Institute and McGill University. It is an inter-university research and training facility that has made Montreal the global centre for the study of the musical brain. Co-directed by Dr. Isabelle Peretz and Dr. Robert Zatorre from the MNI, the Laboratory brings together researchers who share an interest in understanding the cerebral substrates of auditory cognition and, in particular, the processing of music by humans.