Strategy changes and activation of the prefrontal cortex

We investigated the relationship between strategy variations in skill acquisition and the use of prefrontal cortex. We used a computerized mirror drawing task in which the participants repeated tracing a star-shape displayed on a computer monitor using a joystick. Changes of the cerebral blood flow were measured by near infra-red spectroscopy (NIRS). Performance measures were traced lengths and the number of errors. The results suggest that when a human was conducting a skilled performance such as smooth tracing, the decrease of activation of the prefrontal cortex (PFC) was observed. But it was NOT observed when the same human was conducting an unskilled performance. The study also showed that adding or subtracting assistance influenced brain activation and suggested that strategy changes occurred. The activation of PFC can be a useful source of information to know the performance status in skill acquisition and to know appropriate timing of assistance.