According to psychomotor efficiency hypothesis (Hatfield & Hillman, 2001), expert performance is manifested by both physiological and mental efficiency. This efficiency is characterized by reduced cerebral cortical resource for processing psychomotor task demands. Thus, superior performance is accomplished with less effort and fewer neuron assemblies as well as motor units. The efficiency hypothesis is corroborated by a number of studies, which have found that reduced cerebral cortical activity in nonessential regions (e.g., left temporal region of the brain in skilled precision sports athletes) is highly related to skilled motor behavior. Another tenet of the efficiency hypothesis is that the reduction of communication/interference between the nonessential region and motor planning region is associated with superior performance. Deeny, Hillman, Janelle, and Hatfield (2003) empirically proved that the functional connectivity between the left temporal association (T3) and motor planning (Fz) regions of the cerebral cortex, as indexed by EEG coherence, was lower in higher achieved marksmen than in less achieved marksmen. This finding supports the notion that superior performance is accomplished with refined and simplified cerebral cortical processing, and thus supports the efficiency hypothesis. Our study intended to further test the efficiency hypothesis by an intraindividual comparison, in contrast to Deeny et al.'s interindividual comparison. The purpose of this study was to examine the relationship between basketball free-throw performance and communication/ interference among cortical areas. Specifically, the EEG coherences between central frontal site and T3, T4, P3, and P4 for good free throw performance were compared to that of poor free throw performance. We hypothesized that good performance would be associated with lower EEG coherence between the two left hemispheric sites and frontal site. Twelve highly skilled basketball players participated in this study. Each participant was instructed to shoot at least 50 baskets while the EEG was recorded. EEG from two seconds prior to each shot was segmented into four epochs, and classified into either good or poor performance based on whether the ball entered the basket. The coherences of low alpha (8-10 Hz), high alpha (10-13 Hz), and low beta (13-22 Hz) were separately subjected to 2 X 2 X 2 X 4 (performance X laterality X region X epoch) ANOVA. Results showed that EEG coherence across all three-frequency bands for good performance were significantly lower than those for poor performance. In addition, low alpha-coherence in the left parietal and central frontal areas were lower than in the right parietal. In terms of epoch effect, high alpha and low beta coherence decreased as the subject approached ball release. Lower EEG coherence between the frontal, parietal, and temporal areas during good performance suggests that successful performance is associated with less cognitive process interference from the parietal and temporal areas to the motor planning area (frontal). Lower coherence between left parietal and frontal areas implies brain specialization for task performance. The finding that coherence decreases as the subject approaches ball release may suggest an automatic processing for the task.
