Is there a "neural efficiency" in athletes? A high-resolution EEG study.

"Neural efficiency" hypothesis posits that cortical activity is spatially focused in experts. Here we tested the hypothesis that compared to non-athletes, elite athletes are characterized by a reduced cortical activation during visuo-motor tasks related to the field of expertise, as a function of movement side. EEG data (56 channels; EB-Neuro) were continuously recorded in the following right-handed subjects: 11 non-athletes, 11 elite fencing athletes, and 11 elite karate athletes. During the EEG recordings, they observed pictures with fencing and karate attacks, and had to quickly click a right (left) keyboard button for the attacks at right (left) monitor side. The EEG data were averaged with respect to the movement onset, and were spatially enhanced by surface Laplacian estimation. The potentials related to the preparation (readiness potential) and initiation (motor potential) of the movements were measured. For the right movement, the potentials overlying supplementary motor and contralateral sensorimotor areas were higher in amplitude in the non-athletes than in the elite karate and fencing athletes. Furthermore, the amplitude of the motor potential over ipsilateral sensorimotor area was higher in the elite karate than fencing athletes, and its distribution over bilateral sensorimotor areas was less asymmetrical in the karate than in the other two groups. For the left movement, these potentials showed no difference between the groups. The present results suggest that "neural efficiency" hypothesis does not fully account for the organization of motor systems in elite athletes. "Neural efficiency" would depend on several factors including side of the movement, hemisphere, and kind of athletes.

Visual event-related potentials in elite and amateur athletes.

In the present study, we tested the hypothesis that the neural synchronization estimated in visual cortex during visuo-spatial demands shows different features in elite karate athletes when compared to amateur karate athletes and non-athletes. EEG recordings (56 channels; EB-Neuro) were performed from 17 elite karate athletes, 14 amateur karate athletes, and 15 non-athletes, during the observation of pictures with basket and karate attacks. They clicked a right (left) keyboard button for basket or karate attacks at right (left) monitor side. Results pointed to no difference of late occipital VEPs/ERPs after basket versus karate attacks in the non-athletes (300-800 ms post-stimulus). In the amateur karate athletes, occipital VEPs/ERPs at 300-450 ms post-stimulus (P3-P4 components) were lower in amplitude for the karate than basket attacks. In the elite karate athletes, the occipital VEPs/ERPs further declined in amplitude at 300-450 ms post-stimulus (P3 and P4 components) and enhanced at about 800 ms post-stimulus ("N2" component) for the karate than basket attacks. A control study showed that in 10 elite fencers, the same was true for the fencing compared to the karate attacks. These results support the hypothesis that peculiar mechanisms of occipital neural synchronization can be observed in elite athletes during visuo-spatial demands, possibly to underlie sustained visuo-spatial attention and self-control.

Pre-stimulus alpha rhythms are correlated with post-stimulus sensorimotor performance in athletes and non-athletes: a high-resolution EEG study.

OBJECTIVE: In this study, we tested the hypothesis that a pre-stimulus brief (1 min) 10-Hz audio-visual flickering stimulation modulates alpha EEG rhythms and cognitive-motor performance in elite athletes and in non-athletes during visuo-spatial demands. METHODS: Electroencephalographic (EEG) data were recorded (56 channels; EB-Neuro) in 14 elite fencing athletes and in 14 non-athletes during visuo-spatial-motor demands (i.e. subjects had to react to pictures of fencing and karate attacks). The task was performed after pre-stimulus 15- (placebo) or 10-Hz (experimental) flickering audio-visual stimulation lasting 1 min and after no stimulation (baseline). RESULTS: With reference to the baseline condition, only the 10-Hz stimulation induced a negative correlation between pre-stimulus alpha power and reaction time in the fencing athletes and non-athletes as a single group. The higher the enhancement of alpha power before the pictures, the stronger the improvement of the reaction time. The maximum effects were observed in right posterior parietal area (P4 electrode) overlying sensorimotor integrative cortex. Similar results were obtained in a control experiment in which eight elite karate subjects had to react to pictures of karate and basket attacks. CONCLUSIONS: The present results suggest that a preliminary 10-Hz sensory stimulation can modulate EEG alpha rhythms and sensorimotor performance in both elite athletes and non-athletes engaged in visuo-spatial-motor demands. SIGNIFICANCE: Identification of the EEG state of sporting experts prior to their performance provides a plausible rationale for the modulation of alpha rhythms to enhance sporting performance in athletes and sensorimotor performance in patients to be rehabilitated.

Cortical alpha rhythms are correlated with body sway during quiet open-eyes standing in athletes: a high-resolution EEG study.

Electroencephalographic (EEG; Be-plus Eb-Neuro) and stabilogram (RGM) data were simultaneously recorded in 19 elite karate and 18 fencing athletes and in 10 non-athletes during quiet upright standing at open- and closed-eyes condition in order to investigate the correlation between cortical activity and body sway when the visual inputs are available for balance. Our working hypothesis is that, at difference of non-athletes, athletes are characterized by enhanced cortical information processing as indexed by the amplitude reduction of EEG oscillations at alpha rhythms (about 8-12 Hz) during open- referenced to closed-eyes condition (event-related desynchronization, ERD). Balance during quiet standing was indexed by body "sway area". Correlation between alpha ERD and event-related change of the sway area was computed by a non-parametric test (p<0.05). It was found that alpha ERD (10-12 Hz) is stronger in amplitude in the karate and fencing athletes than in the non-athletes at ventral centro-parietal electrodes of the right hemisphere (p<0.02). Furthermore, there was a statistically significant correlation in the karate athletes between right ventral centro-parietal alpha ERD and body sway area (r=0.61; p<0.008): specifically, the greater the alpha ERD, the greater the percentage reduction of the body sway area when the visual inputs were available. These results suggest that parasylvian alpha ERD of the right hemisphere may reflect the cortical information processing for the balance in elite athletes subjected to a long training for equilibrium control.