Learning of motor control is crucial not only for sports or music, but also for craft production, vocational training, or rehabilitation of patients. Motor learning has been long studied with mirror drawing in psychology. However, the neuropsychological mechanism of the learning process has not been well understood, yet. To this end, the present study used a mirror drawing task to examine the changes in the performance before and after practicing the task, while the changes in cerebral blood flow (CBF) was monitored during the task with a Near Infrared Spectroscopy (NIRS) to evaluate cortical activation underlying the developmental process.
In the experimental sessions, participants performed a star-shape drawing on a PC tablet. We set two conditions of drawing hand and two conditions on the cursor movement of the pen; moving normally or moving like a mirror in which the pen moves to the opposite to the normal direction on the monitor. The 32 students, all right-handed, participated and allotted in the either of the four conditions. They run the drawing trials thirty times a day for consecutive three days. Although the task was difficult at the beginning, they improved their performance as the training session proceeded. Hemodynamic changes were monitored on the first trial of the first day and the last trials on the second and the third days. Hemodynamic activation was observed significantly large in the first trial; especially, strong bilateral activations were observed with non-dominant hand conditions. However, dominant hand drawings did not induce much activation in either mirror conditions.
The results indicated that NIRS can clearly detect hemodynamic activation in a new motor learning such as with non-dominant hand, and that such a new motor learning task induced activation not only in the contralateral motor area but also in the bilateral, broad cortical areas.