No abstract

Measurements based on the EEG have featured prominently in shaping present-day concepts of the neurocognitive aspects of skilled performance. The techniques include measurements of spectral power, interelectrode coherence, event-related potential components such as the P300, slow potentials, and the method of cognitive inference. The advantages offered by EEG-based approaches lies in their spatiotemporal resolution (potentially 1 mm and less than 1 millisecond, respectively) and the potential to preserve ecological validity, i.e., to obtain measurements of cortical function under the same conditions that the task is normally performed. These studies indicate that activity is reduced in specific regions of the cerebral cortex of experts relative to that observed in novices. These changes occur over time as a result of practice. The authors argue that such cortical change results in less attentional demand and less cognitive interference with motor planning and execution. The findings attest to the plasticity of the central nervous system when one is engaged in goal-directed learning, and hold implications for understanding how the nervous system acquires voluntary skills, whether in the context of the training of an athlete or the rehabilitation of a patient who has lost motor skills due to a disease of the nervous system.

Momentary reductions in the electrical activity of working muscles (EMG gaps) contribute to the explanation for the relationship between psychosocial stress and musculoskeletal problems in computer work. EMG activity and gaps in the left and right trapezii were monitored in 23 participants under low and high mental workload (LMW and HMW) demands during computer data entry. Increases in EMG activity and decreases in EMG-gap frequencies in both left and right trapezius muscles were greater during HMW than LMW. In addition, heart period and end-tidal CO2 were lower during HMW, whereas self-reported mood states were higher during HMW. The correspondence between lower end-tidal CO2 and lower EMG-gap frequencies suggests that hyperventilation (overbreathing) may mediate trapezius muscle activation. The reduction of EMG gaps suggests that the salutary benefits of momentary rest from musculoskeletal work are diminished during mental stress.

Electroencephalographic (EEG) and self-report measures of affect were obtained from 27 participants (14 F, 13 M) before, during, and following 30 min of continuous exercise at low and high intensities to determine the respective temporal courses of affective response. Mood was measured via a visual analog mood scale (VAMS), the Positive and Negative Affect Schedules (PANAS-PA and -NA), and EEG hemispheric asymmetry as obtained from three electrode pairs: F4-F3, F8-F7, and P4-P3. Participants reported higher VAMS and lower PANAS-NA scores during low-intensity exercise relative to baseline, and the higher scores were maintained during recovery. In contrast, they reported lower scores on the VAMS during high-intensity exercise relative to baseline that were subsequently elevated during recovery. Also, during high-intensity exercise the PANAS-NA scores were similar to baseline, but they were lower during recovery. Both the VAMS and PANAS-NA scores observed after exercise were similar regardless of intensity. Additionally, participants had higher PANAS-PA and EEG hemispheric asymmetry scores (i.e., F8-F7) during exercise at both intensities relative to baseline, then reported values similar to baseline levels on cessation of work. The magnitude of change from baseline for the PANAS-PA and EEG scores during exercise was similar regardless of exercise intensity.

The results support specificity of the physical activity/cognition relationship in older individuals. The results may be explained by additive benefit from participation in physical activity to the frontal lobe (i.e., beyond any benefits from cognitive stimulation), a region that mediates executive function and experiences accelerated age-related decline. In summary, habitual physical activity is positively related to executive performance in older men and women into the 10th decade.

Forty-five (22 women) sedentary young (18-30 years old) nonsmoking normotensive volunteers engaged in either 6 weeks of aerobic training (AT), weight training (WT), or a no-treatment (NT) condition to determine whether AT lowers systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), and rate-pressure product (RPP) during rest, psychological stress, and recovery periods. Estimated VO(2)max increased for the AT (32.1+/-1.1 to 38.4+/-1.0 ml.kg(-1).min(-1)). A smaller increase for the WT (30.5+/-1.1 to 33.8+/-1.0) was likely due to increased leg strength, and VO(2)max did not change for the NT (32.5+/-1.1 to 32.9+/-1.0). Heart rate and RPP levels were lower during psychological stress and recovery after training for AT relative to the WT and NT. Overall SBP was also lower in the AT relative to the NT but not the WT. In conclusion, aerobic training lowered cardiovascular activity levels during psychological stress and recovery in healthy young adults, implying a protective role against age-related increases in coronary heart disease for individuals who adopt aerobic exercise early in life and maintain the behavior across the life span.

No abstract

Motor readiness, visual attention, and reaction time (RT) were assessed in 15 elite table tennis players (TTP) and 15 controls (C) during Posner’s cued attention task. Lateralized readiness potentials (LRP) were derived from contingent negative variation (CNV) at Sites C3 and C4, elicited between presentation of directional cueing (S1) and the appearance of the imperative stimulus (S2), to assess preparation for hand movement while P1 and N1 component amplitudes were derived from occipital event-related potentials (ERPs) in response to S2 to assess visual attention. Both groups had faster RT to validly cued stimuli and slower RT to invalidly cued stimuli relative to the RT to neutral stimuli that were not preceded by directional cueing, but the groups did not differ in attention benefit or cost. However, TTP did have faster RT to all imperative stimuli; they maintained superior reactivity to S2 whether preceded by valid, invalid, or neutral warning cues. Although both groups generated LRP in response to the directional cues, TTP generated larger LRP to prepare the corresponding hand for movement to the side of the cued location. TTP also had an inverse cueing effect for N1 amplitude (i.e., amplitude of N1 to the invalid cue > amplitude of N1 to the valid cue) while C visually attended to the expected and unexpected locations equally. It appears that TTP preserve superior reactivity to stimuli of uncertain location by employing a compensatory strategy to prepare their motor response to an event associated with high probability, while simultaneously devoting more visual attention to an upcoming event of lower probability.