Sport, Bewegung, Training und das zentrale Nervensystem

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Purpose</jats:title> <jats:p>Exhaustive cardiovascular load can affect neural processing and is associated with decreases in sensorimotor performance. The purpose of this study was to explore intensity-dependent modulations in brain network efficiency in response to treadmill running assessed from resting-state electroencephalography (EEG) measures.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Sixteen trained participants were tested for individual peak oxygen uptake (VO<jats:sub>2 peak</jats:sub>) and performed an incremental treadmill exercise at 50% (10 min), 70% (10 min) and 90% speed VO<jats:sub>2 peak</jats:sub> (all-out) followed by cool-down running and active recovery. Before the experiment and after each stage, borg scale (BS), blood lactate concentration (B<jats:sub>La</jats:sub>), resting heartrate (HR<jats:sub>rest</jats:sub>) and 64-channel EEG resting state were assessed. To analyze network efficiency, graph theory was applied to derive small world index (SWI) from EEG data in theta, alpha-1 and alpha-2 frequency bands.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Analysis of variance for repeated measures revealed significant main effects for intensity on BS, B<jats:sub>La</jats:sub>, HR<jats:sub>rest</jats:sub> and SWI. While BS, B<jats:sub>La</jats:sub> and HR<jats:sub>rest</jats:sub> indicated maxima after all-out, SWI showed a reduction in the theta network after all-out.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Our explorative approach suggests intensity-dependent modulations of resting-state brain networks, since exhaustive exercise temporarily reduces brain network efficiency. Resting-state network assessment may prospectively play a role in training monitoring by displaying the readiness and efficiency of the central nervous system in different training situations.</jats:p> </jats:sec>

<jats:title>Abstract </jats:title><jats:p>Mobile Electroencephalography (EEG) provides insights into cortical contributions to postural control. Although changes in theta (4–8 Hz) and alpha frequency power (8–12 Hz) were shown to reflect attentional and sensorimotor processing during balance tasks, information about the effect of stance leg on cortical processing related to postural control is lacking. Therefore, the aim was to examine patterns of cortical activity during single-leg stance with varying surface stability. EEG and force plate data from 21 healthy males (22.43 ± 2.23 years) was recorded during unipedal stance (left/right) on a stable and unstable surface. Using source-space analysis, power spectral density was analyzed in the theta, alpha-1 (8–10 Hz) and alpha-2 (10–12 Hz) frequency bands. Repeated measures ANOVA with the factors leg and surface stability revealed significant interaction effects in the left (<jats:italic>p</jats:italic> = 0.045, <jats:italic>η</jats:italic><jats:sub><jats:italic>p</jats:italic></jats:sub><jats:sup>2</jats:sup> = 0.13) and right motor clusters (<jats:italic>F</jats:italic> = 16.156; <jats:italic>p</jats:italic> = 0.001, <jats:italic>η</jats:italic><jats:sub><jats:italic>p</jats:italic></jats:sub><jats:sup>2</jats:sup> = 0.41). Furthermore, significant main effects for surface stability were observed for the fronto-central cluster (theta), left and right motor (alpha-1), as well as for the right parieto-occipital cluster (alpha-1/alpha-2). Leg dependent changes in alpha-2 power may indicate lateralized patterns of cortical processing in motor areas during single-leg stance. Future studies may therefore consider lateralized patterns of cortical activity for the interpretation of postural deficiencies in unilateral lower limb injuries.</jats:p>

<jats:p>Whereas initial findings have already identified cortical patterns accompanying proprioceptive deficiencies in patients after anterior cruciate ligament reconstruction (ACLR), little is known about compensatory sensorimotor mechanisms for re-establishing postural control. Therefore, the aim of the present study was to explore leg dependent patterns of cortical contributions to postural control in patients 6 weeks following ACLR. A total of 12 patients after ACLR (25.1 ± 3.2 years, 178.1 ± 9.7 cm, 77.5 ± 14.4 kg) and another 12 gender, age, and activity matched healthy controls participated in this study. All subjects performed 10 × 30 s. single leg stances on each leg, equipped with 64-channel mobile electroencephalography (EEG). Postural stability was quantified by area of sway and sway velocity. Estimations of the weighted phase lag index were conducted as a cortical measure of functional connectivity. The findings showed significant group × leg interactions for increased functional connectivity in the anterior cruciate ligament (ACL) injured leg, predominantly including fronto−parietal [<jats:italic>F</jats:italic><jats:sub>(1, 22)</jats:sub> = 8.41, <jats:italic>p</jats:italic> ≤ 0.008, η<jats:sup>2</jats:sup> = 0.28], fronto−occipital [<jats:italic>F</jats:italic><jats:sub>(1, 22)</jats:sub> = 4.43, <jats:italic>p</jats:italic> ≤ 0.047, η<jats:sup>2</jats:sup> = 0.17], parieto−motor [<jats:italic>F</jats:italic><jats:sub>(1, 22)</jats:sub> = 10.30, <jats:italic>p</jats:italic> ≤ 0.004, η<jats:sup>2</jats:sup> = 0.32], occipito−motor [<jats:italic>F</jats:italic><jats:sub>(1, 22)</jats:sub> = 5.21, <jats:italic>p</jats:italic> ≤ 0.032, η<jats:sup>2</jats:sup> = 0.19], and occipito−parietal [<jats:italic>F</jats:italic><jats:sub>(1, 22)</jats:sub> = 4.60, <jats:italic>p</jats:italic> ≤ 0.043, η<jats:sup>2</jats:sup> = 0.17] intra−hemispherical connections in the contralateral hemisphere and occipito−motor [<jats:italic>F</jats:italic><jats:sub>(1, 22)</jats:sub> = 7.33, <jats:italic>p</jats:italic> ≤ 0.013, η<jats:sup>2</jats:sup> = 0.25] on the ipsilateral hemisphere to the injured leg. Higher functional connectivity in patients after ACLR, attained by increased emphasis of functional connections incorporating the somatosensory and visual areas, may serve as a compensatory mechanism to control postural stability of the injured leg in the early phase of rehabilitation. These preliminary results may help to develop new neurophysiological assessments for detecting functional deficiencies after ACLR in the future.</jats:p>

<jats:title>Abstract</jats:title><jats:p>The interaction of acute exercise and the central nervous system evokes increasing interest in interdisciplinary research fields of neuroscience. Novel approaches allow to monitor large-scale brain networks from mobile electroencephalography (EEG) applying graph theory, but it is yet uncertain whether brain graphs extracted after exercise are reliable. We therefore aimed to investigate brain graph reliability extracted from resting state EEG data before and after submaximal exercise twice within one week in male participants. To obtain graph measures, we extracted global small-world-index (SWI), clustering coefficient (CC) and characteristic path length (PL) based on weighted phase leg index (wPLI) and spectral coherence (Coh) calculation. For reliability analysis, Intraclass-Correlation-Coefficient (ICC) and Coefficient of Variation (CoV) were computed for graph measures before (REST) and after POST) exercise. Overall results revealed poor to excellent measures at PRE and good to excellent ICCs at POST in the theta, alpha-1 and alpha-2, beta-1 and beta-2 frequency band. Based on bootstrap-analysis, a positive effect of exercise on reliability of wPLI based measures was observed, while exercise induced a negative effect on reliability of Coh-based graph measures. Findings indicate that brain graphs are a reliable tool to analyze brain networks in exercise contexts, which might be related to the neuroregulating effect of exercise inducing functional connections within the connectome. Relative and absolute reliability demonstrated good to excellent reliability after exercise. Chosen graph measures may not only allow analysis of acute, but also longitudinal studies in exercise-scientific contexts. </jats:p>