Visuomotor expertise and dimensional complexity of cerebral cortical activity.

Purpose: This study employed the correlation dimension (D2) to examine whether visuomotor expertise was inversely related to the complexity of cerebral cortical activity.

Method: Expert rifle shooters (N = 15) and novices (N = 21) completed 40 shots in the standing position during which the electroencephalogram (EEG) was recorded at 10 sites (F3, F4, C3, C4, T3, T4, P3, P4, O1, and O2) during a 5-s aiming period prior to trigger pull. D2 was derived for each trial and averaged across shots. A 2 x 2 x 5 (group x cerebral hemisphere x region) ANOVA was employed to contrast D2, while correlation analyses were used to determine the relationship between D2 and target shooting accuracy as well as variability of shot placement.

Results: As predicted, experts exhibited lower D2 (5.02 +/- 0.16 vs 5.49 +/- 0.13, respectively) and greater accuracy of shot placement ((339.8 +/- 44.7 vs 90.7 +/- 38.9 points out of 400 possible, respectively). Experts also exhibited an inverse relationship between D2 and shooting accuracy, while, in contrast, novices revealed a positive relationship.

Discussion: The results suggest that refinement and efficiency of cerebral cortical activity facilitates visuomotor performance. Lower complexity may be associated with less neuromotor "noise" in the brain, thus reducing interference with intended action.