Tuesday, 21 September 2010

Do musicians have different brains?

Does musical training reorganise the brain? What are the implications? 

In the last twenty years, brain imaging studies have revealed that musical training has dramatic effects on the brain. Increases in gray matter (size and number of nerve cells) are seen, for example, in the auditory, motor, and visual spatial areas of the cerebral cortex of musicians.
As Dr. Oliver Sacks writes in his book Musicophilia, "Anatomists would be hard put to identify the brain of a visual artist, a writer, or a mathematician - but they could recognize the brain of a professional musician without a moment's hesitation." Perhaps it is not so surprising that brain areas involved in singing and instrument playing, such as auditory and motor cortices, change following extensive musical training, but a recent paper in the journal Neuroscience suggests yet another way that music reshapes the brain.

Musicians may not only have better musical memory but they may have enhanced verbal memory as well. They may be better, for example, at recalling a list of random words. In the study mentioned above, the scientists investigated what parts of the brain were involved in this improved verbal memory. They recruited twenty female college students for their experiment. Ten of the students had had no musical training while the other ten had started piano lessons before the age of 7 and continued with the training for a period of more than 8 years. The authors stressed that none of the musically trained students were professionals, and there was no reason to believe they were particularly gifted in music. Many probably learned to play the piano because their parents wanted them to.
 
In the experiment, all the students listened to and attempted to remember a set of 20 words. Then, they heard another list of 40 words which contained in random order the previously heard words and 20 new ones. The students had to indicate which words were "old" and which were "new." All these tests were done while their brain activity was monitored in an MRI machine.

This memory task turned out to be pretty easy, and both groups of students did very well although the musically trained students did a little better. When first hearing the words, the same brain areas were activated in both student groups. What was surprising however were the areas that were activated when the students had to determine whether or not they had heard the word before. In the musically trained but not the untrained group, the visual cortex was activated during this word retrieval task. The visual cortex? In the past, this area of the brain was thought to process visual information only and recalling heard words is not a visual task. Perhaps, the musical students, during their years of training, had learned to recruit their visual cortex to help them remember the music they were playing. Now, they could use this visual area in recalling words.

This study suggests a whole new effect of musical training, or training in general, on the nervous system. Long-term musical training actually re-organizes the brain. Areas that are initially devoted to one type of function (vision), may be recruited to perform another (verbal memory). This reorganization may take place following the learning of a very demanding set of skills. Piano playing, which requires competence in many areas, i.e. hearing pitches, sensing rhythms, reading music, and hand coordination, is an example of such a challenging task.

So I can end this post on a positive note. Studies such as this one give hope to people who have suffered brain injuries such as strokes. If we can re-organize our brains and learn to use our visual cortex to help remember words, then perhaps stroke victims can reorganize their brains as well. Perhaps, they can learn to use undamaged areas to perform tasks once under the control of an injured part of the brain. This won't happen spontaneously however. It requires doctors, therapists, and patients to develop new therapies that step-by-step require and teach patients to regain lost abilities and skills.

Reference for the paper discussed above: 
Huang Z et al (2010) Verbal memory retrieval engages visual cortex in musicians. Neuroscience 168:179-189.

ABSTRACT

AIM: As one major line of research on brain plasticity, many imaging studies have been conducted to identify the functional and structural reorganization associated with musical expertise.Based on previous behavioral research, the present study used functional magnetic resonance imaging to identify the neural correlates of superior verbal memory performance in musicians.

METHOD: Participants with and without musical training performed a verbal memory task to first encode a list of words auditorily delivered and then silently recall as many words as possible. They performed in separate blocks a control task involving pure tone pitch judgment.

RESULTS: Post-scan recognition test showed better memory performance in musicians than non-musicians. During memory retrieval, the musicians showed significantly greater activations in bilateral though left-lateralized visual cortex relative to the pitch judgment baseline. In comparison, no such visual cortical activations were found in the non-musicians. No group differences were observed during the encoding stage.

CONCLUSION: The results echo a previous report of visual cortical activation during verbal memory retrieval in the absence of any visual sensory stimulation in the blind population, who are also known to possess superior verbal memory. It is suggested that the visual cortex can be recruited to serve as extra memory resources and contributes to the superior verbal memory in special situations. While in the blind population, such cross-modal functional reorganization may be induced by sensory deprivation; in the musicians it may be induced by the long-term and demanding nature of musical training to use as much available neural resources as possible.

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