The influence of expertise on brain activation of the action observation network during anticipation of tennis and volleyball serves

Abstract

In many daily activities, and especially in sport, it is necessary to predict the effects of others' actions in order to initiate appropriate responses. Recently, researchers have suggested that the action-observation network (AON) including the cerebellum plays an essential role during such anticipation, particularly in sport expert performers. In the present study, we examined the influence of task-specific expertise on the AON by investigating differences between two expert groups trained in different sports while anticipating action effects. Altogether, 15 tennis and 16 volleyball experts anticipated the direction of observed tennis and volleyball serves while undergoing functional magnetic resonance imaging (fMRI). The expert group in each sport acted as novice controls in the other sport with which they had only little experience. When contrasting anticipation in both expertise conditions with the corresponding untrained sport, a stronger activation of AON areas (SPL, SMA), and particularly of cerebellar structures, was observed. Furthermore, the neural activation within the cerebellum and the SPL was linearly correlated with participant's anticipation performance, irrespective of the specific expertise. For the SPL, this relationship also holds when an expert performs a domain-specific anticipation task. Notably, the stronger activation of the cerebellum as well as of the SMA and the SPL in the expertise conditions suggests that experts rely on their more fine-tuned perceptual-motor representations that have improved during years of training when anticipating the effects of others' actions in their preferred sport. The association of activation within the SPL and the cerebellum with the task achievement suggests that these areas are the predominant brain sites involved in fast motor predictions. The SPL reflects the processing of domain-specific contextual information and the cerebellum the usage of a predictive internal model to solve the anticipation task.

Keywords: cerebellum; functional magnetic resonance imaging; motor expertise; sports-related anticipation; superior parietal lobe.

Figure 1

Screenshots of all four experimental conditions. Each of the 128 video clips lasted 2.9–4.6 s. (A) Male tennis player performing a tennis serve (Tennis Anticipation condition). (B) Female volleyball player performing a volleyball serve (Volleyball Anticipation condition). All serve sequences were stopped at ball–racket respective ball–hand contact. (C) Female tennis player bouncing the ball with her racket (Tennis Observation condition). (D) Male volleyball player bouncing the ball with his hand (Volleyball Observation condition).

Figure 2

Mean percentage of correct responses in the Tennis Anticipation and the Volleyball Anticipation condition of the tennis experts and the volleyball experts. Bars represent SD.

Figure 3

In the middle of the figure: Significant brain activation in all 31 participants for the contrast (Expertise Anticipation > Expertise Observation) > (Novice Anticipation > Novice Observation). The blue vertical and horizontal lines indicate the slice positions. T maps were thresholded at t = 2.00 (p < 0.05, FWE-corrected). Activation is rendered on a high-resolution T1 template (“colin brain”) as well as on the cerebellar SUIT template (Diedrichsen, 2006). Upper and lower part of the figure: Mean percent signal changes and standard errors in the preSMA, the SPL, and in Lobule VI and VIIIa of the cerebellum for the contrasts Tennis Anticipation > Tennis Observation and Volleyball Anticipation > Volleyball Observation, separated for both expertise groups. The signal changes were calculated by means of the SPM toolbox rfxplot (Gläscher, ; http://rfxplot.sourceforge.net).

Figure 4

(A) Brain areas showing significantly stronger activation as a function of the number of correct responses for the contrast Tennis and Volleyball Anticipation > Tennis and Volleyball Observation in all 31 participants (red marks). (B) Brain areas showing significantly stronger activation as a function of the number of correct responses in serve anticipation in the expertise sport for the contrast Expertise Anticipation > Expertise Observation in all 31 participants (blue marks). T maps were thresholded at t = 1.00 (p < 0.05, FWE-corrected). Activation is rendered on a high-resolution T1 template (“colin brain”) as well as on the cerebellar SUIT template (Diedrichsen, 2006).