There is evidence to suggest that other experts have structural and functional brain differences compared to controls, so it's possible that expertise in other sports or physical activities might also be associated with brain differences.
Dr Ed Roberts
Recently published in the Journal Cerebral Cortex
, research by scientists at Imperial College London and University College London (UCL) has established a link between the structure of white matter and punching ability in karate experts. With previous studies having shown that muscular strength is not the deciding factor for packing a powerful punch, this experiment demonstrates the correlation between experience and ability.
12 black belts with an average of 13.8 years karate experience and 12 novices from the same age range were compared on the force of their punch at a distance of 5 cm. Differences were detected in the white matter of the karate experts in the cerebellum and the primary motor cortex. The association of these areas with controlling movement suggests that the differences are related to finely honed coordination skills.
I addressed some questions to Dr Ed Roberts, the research associate in the Department of Medicine at Imperial College London who led the study, and he was able to explain its methodology and findings in greater detail…
What prompted you to carry out this study?
As much of the research on how the brain controls movement has been based on examining how diseases can impair
motor skills, we were interested in taking a different approach by looking at what enables experts to perform better than novices in tests of physical skill. We hoped that this might reveal brain areas which have become optimised for performance of a particular task.
What technique did you use to measure the power of punches and how did you combine this with looking at brain structure? What significant differences did the results show between brain structure in the karate experts and the non-experts?
The scans used in this study, called diffusion tensor imaging (DTI), detected structural differences in the white matter of parts of the brain called the cerebellum and the primary motor cortex, which are known to be involved in controlling movement. Each brain region is composed of grey matter, consisting of the main bodies of nerve cells, and white matter, which is mainly made up of bundles of fibres that carry signals from one region to another.
We then measured performance during punching using infrared markers to monitor the position of the upper body and arms whilst the participants punched a force plate from a short distance.
The differences measured by DTI in the cerebellum correlated with the synchronicity of the subjects’ wrist and shoulder movements when punching. The DTI signal also correlated with the age at which karate experts began training and their total experience of the discipline. These findings suggest that the structural differences in the brain are related to the black belts’ punching ability.
Why do you think these differences exist and could they apply to other actions related to other sports or physical activities?
The locations (in white) in the cerebellum and motor cortex where differences were observed between groups.
It is possible that the differences are a result of many years of karate training, but to confirm this hypothesis we would have to scan people before they started training and then again a number of years later. There is evidence to suggest that other experts have structural and functional brain differences compared to control subjects, so it's possible that expertise in other sports or physical activities might also be associated with brain differences. I would predict that such differences are likely to be quite specific to a particular activity.
How will we begin to understand more about the mechanisms at work here? What are the next steps for your research?
Our understanding of how the brain changes with experience – plasticity – is still quite limited, so the next step for research into expertise would be to look at longitudinal studies to examine how brain changes occur over time and whether similar brain regions are involved. Some of my colleagues at Imperial College are currently exploring how brain structure is related to motor expertise in professional dancers, and hopefully this will shed more light on how expertise is encoded in the structure of the brain.