Performance Types and Activation of the Prefrontal Cortex

We investigated the relationship between performance types in skill acquisition and the use of the prefrontal cortex (PFC). We used a modified mirror drawing task in which participants using a pen tablet repeated the tracing of a star displayed on a screen. Changes in cerebral blood flow were measured using near infrared spectroscopy (NIRS). Participants conducted two tasks, mirror drawing, i.e., tracing a mirror image of a star, and an usual drawing, i.e., tracing a star. Performance was scored based on the number of errors and drawn lengths. Results suggested that two types of participants - those whose number of errors decreased when they repeated the task and those whose number of errors did not decrease. We thus concluded that (1) changes in oxy-hemoglobin concentration (Oxy-Hb) are higher in the mirror drawing task than in the usual drawing task; (2) oxy-Hb decreased in the right PFC when participants whose number of errors decreased repeated the task 4 days later, but did not decrease in the left PFC; (3) oxy-Hb decreased in the left PFC when participants whose number of errors did not decrease repeated the task 4 days later, but did not decrease in the right PFC. Our findings indicate that activation of the PFC can be used to assess skill levels in on-going tasks and may provide information on how to time assistance.