Professional musicians make excellent subjects for neuropsychology research. Music performance requires a complex interaction of auditory and touch sensory perception, bimanual coordination, muscle memory and fine motor control, all directed to shape the artistic interpretation of the music. Expert musicians often begin their study at a young age, during the ‘critical period’ of neural development when the synapses or neural connections in the brain are most malleable. Humans are born with an enormous number of neurons and the synaptic connections are formed and strengthened through experience. The brain becomes more efficient at knowing what neurons are needed for what tasks. The more familiar a pathway becomes, the easier it becomes to complete and the fewer resources it needs to reach completion. This essentially ‘frees up’ more neural resources that are then available for use in other areas of the brain. This adaptive plasticity shapes the brain throughout the lifetime. The earlier such optimization can start, however, the greater its potential effects.

In a recent study, Vaquero et al. compared the structural neuroplasticity of expert pianists who had begun their musical training either before or after the age of 7, using non-musicians as the baseline comparison. The pianists were similar in skill level, practiced similar hours, and studied at the same school in Hannover. Of the 36 pianists, 21 began study before the age of 7 (average=5.19 years old), 15 began study at or after the age of 7 (average=8.33 years old). Their piano playing skill was assessed by playing C-major scales on a piano hooked into a computer. The evenness of the keystrokes was analyzed by averaging the interval between each keystroke. The greater the recorded unevenness, the more imprecise the timing and motor control for that hand. As a tool to study the neural adaptivity of habitual motor pathways, this is an excellent test. C-major is not perhaps the easiest scale to play but it is often the first scale learned.

All participants were right handed and they all played the scales more unevenly in their left hand. However, the late age-of-onset pianists were more uneven in both hands than their early age-of-onset peers. When the brain scans of all three groups were analyzed, the researchers found differences between the musicians and non-musicians in the estimated volume of grey matter (GMV) in the basal ganglia: the musicians had more GMV in that area. The basal ganglia in an important control center for motor behaviours and learned responses in the brain. It lies beneath the cortex and it is a key component of the ‘motor loop’. This study focused on the greater grey matter volume (GMV) found in the part of this system called the putamen. This is the area of learned, habitual motor memory, the type of movement that is performed so often that it becomes automatic. The putamen receives information from the areas of conscious, explicit movement in the outer motor cortices and it sends out directives for the completion of that movement along its habituated path. The basal ganglia connects the associative, motor, and sensory areas of the brain, the thalamus (which is the brain’s switchboard), the limbic system (the area responsible for memory encoding and emotional responses), and the nucleus accumbens (the brain’s reward and evaluation processor). The brain scans from this study also show increased GMV in the limbic system and right thalamus, as well as increases in the language comprehension processing areas in the left hemisphere and the visual processing areas as compared with the non-musician controls.

The piano is incredibly touch sensitive and the player must be both responsive and anticipatory to the sound. The more automatic the motor responses, the more attention can be afforded other areas of performance. The more even the motor response, the more consistent the touch and the better the overall sound. It is no surprise that musicians would have a significantly larger GMV in the putamen as the brain responds to experience and training by recruiting more neurons and strengthening the synaptic connections. However, what this study found was that the earlier the age-of-onset, the smaller the amount of GMV in the putamen compared to those with a later age-of-onset. Despite only three years of difference in age-of-onset between the two groups, the smaller GMV indicates that the earlier the start of training, the more efficient the brain becomes at this motor automaticity.

This does not mean a pianist must begin to study before the age of 7 or else all is lost. The degree of evenness in a C-major scale does not equate to a pianist’s musicality or technical skill. However, this correlation of evenness in the left hand to the GMV optimization in the right putamen indicates that the earlier the start of music training, the more advantageous that training will be to the areas of the brain relating to the motor response automaticity.

Reference:

Vaquero, L., Hartmann, K., Ripollés, P., Rojo, N., Sierpowska, J., François, C., & … Altenmüller, E. (2016). Structural neuroplasticity in expert pianists depends on the age of musical training onset. Neuroimage, 126106-119. doi:10.1016/j.neuroimage.2015.11.008