Stroboscopic vision prolongs visual motion perception in the central nervous system.

Stroboscopic training has repeatedly been shown to improve visual and visuomotor performance in sports. Although recent research suggests that stroboscopic vision puts a training stimulus to the central nervous system, the underlying mechanism how it affects motion perception and processing in the brain is still unknown. Twenty-six participants performed a computer-based simple reaction test in response to a visual motion stimulus under normal (baseline) and stroboscopic conditions (5 Hz frequency, 40% duty cycle) (stroboscopic). A third condition under normal vision intermittently stopped the motion stimulus at the same frequency and duty cycle as in the stroboscopic condition. This condition controlled for the amount of visual motion information independent of the shutter glasses (screen shutter) and provided information about the effect of luminance changes induced by the stroboscopic eyewear. A 64-channel EEG was recorded to determine the amplitude and latency of the N2 component as a correlate of visual motion perception in the motion-sensitive visual area MT. Reaction time under stroboscopic conditions was significantly delayed when compared to both the baseline (p < 0.001) and screen shutter (p < 0.001) conditions. This was accompanied by a significantly prolonged N2 latency (p < 0.001) and lower N2 amplitude (p < 0.001) with the shutter glasses. There was no difference in reaction time or N2 amplitude/latency between the baseline and screen shutter condition (p ≥ 0.176). Stroboscopic eyewear delays the speed of visual motion perception and processing in the central nervous system and reduces the visuomotor reaction speed. This may form the neurophysiological basis for performance gains following stroboscopic training.

Effects of Endurance Exercise Bouts in Hypoxia, Hyperoxia, and Normoxia on mTOR-Related Protein Signaling in Human Skeletal Muscle.

Przyklenk, A, Aussieker, T, Gutmann, B, Schiffer, T, Brinkmann, C, Strüder, HK, Bloch, W, Mierau, A, and Gehlert, S. Effects of endurance exercise bouts in hypoxia, hyperoxia, and normoxia on mTOR-related protein signaling in human skeletal muscle. J Strength Cond Res 34(8): 2276-2284, 2020-This study investigated the effects of short-term hypoxia (HY), hyperoxia (PER), and normoxia on anabolic signaling proteins in response to an acute bout of moderate endurance exercise (EEX) before and after an endurance exercise training intervention. Eleven healthy male subjects conducted one-legged cycling endurance exercise (3 × 30 min·wk for 4 weeks). One leg was trained under hypoxic (12% O2) or hyperoxic conditions (in a randomized cross-over design), and the other leg was trained in normoxia (20.9% O2) at the same relative workload. Musculus vastus lateralis biopsies were taken at baseline (T0) as well as immediately after the first (T1) and last (T2) training session to analyze anabolic signaling proteins and the myofiber cross-sectional area (FCSA). No significant differences were detected for FCSA between T0 and T2 under all oxygen conditions (p > 0.05). No significant differences (p > 0.05) were observed for BNIP3, phosphorylated RSK1, ERK1/2, FoxO3a, mTOR, and S6K1 between all conditions and time points. Phosphorylated Akt/PKB decreased significantly (p < 0.05) at T1 in PER and at T2 in HY and PER. Phosphorylated rpS6 decreased significantly (p < 0.05) at T1 only in PER, whereas nonsignificant increases were shown in HY at T2 (p = 0.10). Despite no significant regulations, considerable reductions in eEF2 phosphorylation were detected in HY at T1 and T2 (p = 0.11 and p = 0.12, respectively). Short-term hypoxia in combination with moderate EEX induces favorable acute anabolic signaling responses in human skeletal muscle.

Motion-Onset Visual Potentials Evoked in a Sport-Specific Visuomotor Reaction Task.

Although neural visual processes play a crucial role in sport, experiments have been restricted to laboratory conditions lacking ecological validity. Therefore, this study examined the feasibility of measuring visual evoked potentials in a sport-specific visuomotor task. A total of 18 international elite young table tennis athletes (mean age 12.5 years) performed a computer-based and a sport-specific visuomotor reaction task in response to radial motion-onset stimuli on a computer screen and table tennis balls played by a ball machine, respectively. A 64-channel electroencephalography system identified the N2 and N2-r motion-onset visual evoked potentials in the motion-sensitive midtemporal visual area. Visual evoked potential amplitudes were highly correlated between conditions (N2 r = .72, N2-r r = .74) although significantly lower in the sport-specific task than in the lab-based task (N2 p < .001, N2-r p < .001). The results suggest that sport-specific visual stimulation is feasible to evoke visual potentials. This emphasizes the investigation of visual processes under more ecologically valid conditions in sport and exercise science.

The Achilles tendon is mechanosensitive in older adults: adaptations following 14†weeks versus 1.5†years of cyclic strain exercise.

The aging musculoskeletal system experiences a general decline in structure and function, characterized by a reduced adaptability to environmental stress. We investigated whether the older human Achilles tendon (AT) demonstrates mechanosensitivity (via biomechanical and morphological adaptations) in response to long-term mechanical loading. Thirty-four female adults (60-75 years) were allocated to either a medium-term (14 weeks; N=21) high AT strain cyclic loading exercise intervention or a control group (N=13), with 12 participants continuing with the intervention for 1.5 years. AT biomechanical properties were assessed using ultrasonography and dynamometry. Tendon cross-sectional area (CSA) was investigated by means of magnetic resonance imaging. A 22% exercise-related increment in ankle plantarflexion joint moment, along with increased AT stiffness (598.2±141.2 versus 488.4±136.9 N mm-1 at baseline), Young's modulus (1.63±0.46 versus 1.37±0.39 GPa at baseline) and about 6% hypertrophy along the entire free AT were identified after 14 weeks of strength training, with no further improvement after 1.5 years of intervention. The aging AT appears to be capable of increasing its stiffness in response to 14 weeks of mechanical loading exercise by changing both its material and dimensional properties. Continuing exercise seems to maintain, but not cause further adaptive changes in tendons, suggesting that the adaptive time-response relationship of aging tendons subjected to mechanical loading is nonlinear.

Cortical Correlates of Human Balance Control.

Balance control is a fundamental component of human every day motor activities such as standing or walking, and its impairment is associated with an increased risk of falling. However, in humans the exact neurobiological mechanisms underlying balance control are still unclear. Specifically, although previous studies have identified a number of cortical regions that become significantly activated during real or imagined balancing, the interactions within and between the relevant cortical regions remain to be investigated. The working hypothesis of this study is that cortical networks contribute to an optimization of balance control, and that this contribution can be revealed by partial directed coherence-a time-variant, frequency-selective and directed functional connectivity analysis tool. Electroencephalographic activity was recorded in 37 subjects during single-leg balancing on a stable as well as an unstable surface. Results of this study show that in the transition from balancing on a stable surface to an unstable surface, two topographically delimitable connectivity networks (weighted directed networks) are established; one associated with the alpha and one with the theta frequency band. The theta network sequence can be described as a set of subnetworks (modules) comprising the frontal, central and parietal cortex with individual temporal and spatial developments within and between those modules. In the alpha network, the occipital electrodes O1 and O2 act as a source, and the interactions propagate predominantly in the directions from occipital to parietal and to centro-parietal areas. These important findings indicate that balance control is supported by at least two functional cortical networks.

Endurance Exercise in Hypoxia, Hyperoxia and Normoxia: Mitochondrial and Global Adaptations.

We hypothesized short-term endurance exercise (EN) in hypoxia (HY) to exert decreased mitochondrial adaptation, peak oxygen consumption (VO2peak) and peak power output (PPO) compared to EN in normoxia (NOR) and hyperoxia (PER). 11 male subjects performed repeated unipedal cycling EN in HY, PER, and NOR over 4 weeks in a cross-over design. VO2peak, PPO, rate of perceived exertion (RPE) and blood lactate (Bla) were determined pre- and post-intervention to assess physiological demands and adaptation. Skeletal muscle biopsies were collected to determine molecular mitochondrial signaling and adaptation. Despite reduced exercise intensity (P<0.05), increased Bla and RPE levels in HY revealed higher metabolic load compared to PER (P<0.05) and NOR (n.s.). PPO increased in all groups (P<0.05) while VO2peak and mitochondrial signaling were unchanged (P>0.05). Electron transport chain complexes tended to increase in all groups with the highest increase in HY (n.s.). EN-induced mitochondrial adaptability and exercise capacity neither decreased significantly in HY nor increased in PER compared to NOR. Despite decreased exercise intensity, short term EN under HY may not necessarily impair mitochondrial adaptation and exercise capacity while PER does not augment adaptation. HY might strengthen adaptive responses under circumstances when absolute training intensity has to be reduced.

Effects of physical exercise on individual resting state EEG alpha peak frequency.

Previous research has shown that both acute and chronic physical exercises can induce positive effects on brain function and this is associated with improvements in cognitive performance. However, the neurophysiological mechanisms underlying the beneficial effects of exercise on cognitive processing are not well understood. This study examined the effects of an acute bout of physical exercise as well as four weeks of exercise training on the individual resting state electroencephalographic (EEG) alpha peak frequency (iAPF), a neurophysiological marker of the individual's state of arousal and attention, in healthy young adults. The subjects completed a steady state exercise (SSE) protocol or an exhaustive exercise (EE) protocol, respectively, on two separate days. EEG activity was recorded for 2 min before exercise, immediately after exercise, and after 10 min of rest. All assessments were repeated following four weeks of exercise training to investigate whether an improvement in physical fitness modulates the resting state iAPF and/or the iAPF response to an acute bout of SSE and EE. The iAPF was significantly increased following EE (P = 0.012) but not following SSE. It is concluded that the iAPF is increased following intense exercise, indicating a higher level of arousal and preparedness for external input.

Impact of exercise on pro inflammatory cytokine levels and epigenetic modulations of tumor-competitive lymphocytes in Non-Hodgkin-Lymphoma patients-randomized controlled trial.

INTRODUCTION: Physical activity is associated with decreased cancer (recurrence) risk and a reduction in treatment-specific side effects. Exercise modulates cytokine expression and shows beneficial effects on cancer patients' immune system. We investigated the following: (i) whether Non-Hodgkin-Lymphoma patients have increased serum macrophage migration inhibiting factor (MIF) and Interleukin-6 (IL-6) levels after immunochemotherapy; (ii) whether physical activity influences cytokine serum levels; and (iii) whether serum cytokine levels are associated with histone modifications in tumor-competitive immune cells. METHODS: Thirty patients and 10 healthy controls were randomised into an intervention and a control group. Participants of the intervention group exercised once for 30 min at moderate intensity on a bicycle ergometer. Blood samples were collected twice, before and after the intervention. MIF and IL-6 serum concentrations were detected by ELISA. Natural killer cells and CD8(+) T-lymphocytes were isolated by magnetic labeled cell sorting. Isolated cells were stained and analyzed for global histone acetylation at histone 4, lysine 5 and histone three, lysine 9. RESULTS: Patients showed higher serum MIF and IL-6 baseline levels, and reduced NK-cell histone acetylation, indicating a reduced transcriptional activity of tumor-competitive lymphocytes. Changes in MIF correlated with altered NK-cell histone acetylation, leading to the hypothesis that MIF impacts NK-cells via epigenetic modifications. Further, the exercise intervention was associated with an increase in IL-6 and CD8(+) T-lymphocyte histone acetylation. CONCLUSIONS: We conclude that exercise induces changes in cytokine levels, thereby possibly affecting epigenetic patterns and activity of tumor-competitive lymphocytes.

Interhemispheric transfer time correlates with white matter integrity of the corpus callosum in healthy older adults.

The corpus callosum (CC) has been identified as an important structure in the context of cognitive aging (Fling et al., 2011). Interhemispheric transfer time (IHTT) is regularly used in order to estimate interhemispheric integration enabled by the CC (Marzi, 2010; Nowicka and Tacikowski, 2011). However, only little is known with regards to the relationship between IHTT and the structural properties of the CC with only few studies with specific samples and methods available (Whitford et al., 2011). Thus, the present study aimed at investigating this relationship applying an event-related potentials (ERP) based approach of estimating IHTT as well as diffusion weighted imaging (DWI) with fractional anisotropy (FA) as an indicator of white matter integrity (WMI) of the genu, corpus and splenium of the CC. 56 healthy older adults performed a Dimond Task while ERPs were recorded and underwent DWI scanning. IHTT derived from posterior electrode sites correlated significantly with FA of the splenium (r = -0.286*, p = .03) but not the corpus (r = -0.187, p = .08) or genu (r = -0.189, p = .18). The present results support the notion that IHTT is related to WMI of the posterior CC. It may be concluded that ERP based IHTT is a suitable indicator of CC structure and function, however, likely specific to the interhemispheric transfer of visual information. Future studies may wish to confirm these findings in a more divers sample further exploring the precise interrelation between IHTT and structural or functional properties of the CC.

Stroboscopic Eyewear Applied During Warm-Up Does Not Provide Additional Benefits to the Sport-Specific Reaction Speed in Highly Trained Table Tennis Athletes.

PURPOSE: While long-term training with stroboscopic eyewear suggests performance-enhancing effects on visuomotor abilities, it remains unclear whether a short-term application, for example, during a warm-up, results in immediate performance gains. This study evaluated potential performance-enhancing effects of stroboscopic eyewear applied during warm-up on reaction speed that may provide athletes an edge in visuomotor-demanding sports. METHODS: Twenty-eight international-level table tennis athletes participated in this study. Participants performed their individual 10-minute table-tennis-specific warm-up under normal visual conditions and with stroboscopic eyewear. Prior to and after the warm-up, visuomotor reaction time was assessed in a sport-specific reaction test where athletes had to return 30 table tennis balls played by a ball machine at high speed to their backhand side. Reaction time was determined as the interval between ball output and movement onset as triggered by a mechanical switch. Furthermore, the time between ball-table contact and ball-racket contact (hit time) was analyzed as an indicator of how early the athletes intercepted the ball. RESULTS: Reaction time significantly improved following the warm-up (P < .001, ηp2=.393). However, there was no additional benefit of the stroboscopic eyewear (P = .338, ηp2=.034). No changes after the warm-up were observed for hit time (P = .246, ηp2=.055). CONCLUSIONS: The results indicate that warm-up facilitated visuomotor reaction speed; however, stroboscopic eyewear did not provide additional positive effects when compared to a warm-up under normal visual conditions. While shutter glasses may be useful for training over longer periods, short-term positive effects were not supported in this study.

The relationship between interhemispheric transfer time and physical activity as well as cardiorespiratory fitness in healthy older adults.

The structural and functional degradation of the corpus callosum (CC) has been shown to play an important role in the context of cognitive aging (Reuter-Lorenz and Stanczak, 2000). This is also reflected by findings of elongated interhemispheric transfer time (IHTT) in older adults (Riedel et al., 2022). At the same time, a protective effect of physical activity (PA) and cardiorespiratory fitness (CRF) on brain health including the CC is widely accepted (Hillman et al., 2008; Loprinzi et al., 2020). Based on this idea, the present study investigated the relationship between IHTT and PA/CRF in 107 healthy older adults (m: 64, f: 43) aged 67.69 ± 5.18. IHTT was calculated detecting event-related potentials (ERPs) using an established Dimond-Task. PA was evaluated using accelerometry resulting in estimates of overall bodily motion and time spent at higher intensity PA. CRF was estimated using graded exercise testing, approximating running speed at 4 mmol/l blood lactate concentration. The results showed a negative correlation between IHTTright→left and PA overall as well as in the male subgroup and between IHTTleft→right and CRF in women. This indicates a potential relationship between IHTT and PA/CRF. While the present investigation is only the first to hint at such a relationship taking into account the differential effects with regards to sex, mode of PA/CRF and IHTT direction, it is in line with previous findings and theoretical suggestions linking brain health to PA/CRF in the context of aging. Further research is needed in order to increase our understanding of the underlying mechanisms and of the influence of sex, PA intensity, degree of CRF and significance of IHTT direction.

The impact of aging on interhemispheric transfer time and respective sex differences.

Age-related cognitive decline has been attributed to degeneration of the corpus callosum (CC), which allows for interhemispheric integration and information processing [22,69]. Along with decreased structural integrity, altered functional properties of the CC may cause impaired cognitive performance in older adults, yet this aspect of age-related decline remains insufficiently researched [59]. In this context, potential sex-related differences have been proposed [31,58]. A promising parameter, which has been suggested to estimate functional properties of the CC is the interhemispheric transfer time (IHTT), which is ideally obtained from event-related potentials (ERP) evoked by lateralized stimuli [45]. To examine the possible functional consequences of aging with regards to the CC, the present study investigated the IHTT of 107 older (67.69 ±â€¯5.18y) as well as of 23 younger participants (25.09 ±â€¯2.59y). IHTT was obtained using an established letter matching task and targeting early N170 ERP components at posterior electrode sites. The results revealed significantly elongated IHTT in older compared to younger participants, but no significant sex differences. Furthermore, there was a significant positive correlation between IHTT and age, predominantly driven by the female participants. The present findings add support to the notion, that IHTT is subject to age-related elongation reflecting impaired interhemispheric transmission. Age-related decline in women appears to occur at a different age range compared to men.

Visual Perception and Visuomotor Reaction Speed Are Independent of the Individual Alpha Frequency.

While the resting-state individual alpha frequency (IAF) is related to the cognitive performance and temporal resolution of visual perception, it remains unclear how it affects the neural correlates of visual perception and reaction processes. This study aimed to unravel the relation between IAF, visual perception, and visuomotor reaction time. One hundred forty-eight (148) participants (28 non-athletes, 39 table tennis players, and 81 badminton players) investigated in three previous studies were considered. During a visuomotor reaction task, the visuomotor reaction time (VMRT) and EMG onset were determined. In addition, a 64-channel EEG system identified the N2, N2-r, and BA6 negativity potentials representing the visual and motor processes related to visuomotor reactions. Resting-state individual alpha frequency (IAF) in visual and motor regions was compared based on sport experience (athletes vs. non-athletes), discipline (badminton vs. table tennis), and reaction performance (fast vs. medium vs. slow reaction time). Further, the differences in the IAF were determined in relation to the speed of neural visual (high vs. medium vs. low N2/N2-r latency) and motor (high vs. medium vs. low BA6 negativity latency). Group comparisons did not reveal any difference in the IAF between athletes and non-athletes (p = 0.352, η p 2 = 0.02) or badminton and table tennis players (p = 0.221, η p 2 = 0.02). Similarly, classification based on the behavioral or neural performance indicators did not reveal any effects on the IAF (p ≥ 0.158, η p 2 ≤ 0.027). IAF was not correlated to any of the behavioral or neural parameters (r ≤ 0.10, p ≥ 0.221). In contrast to behavioral results on cognitive performance and visual temporal resolution, the resting state IAF seemed unrelated to the visual perception and visuomotor reaction speed in simple reaction tasks. Considering the previous results on the correlations between the IAF, cognitive abilities, and temporal sampling of visual information, the results suggest that a higher IAF may facilitate the amount and frequency but not the speed of information transfer.

Short- and Long-Term Stroboscopic Training Effects on Visuomotor Performance in Elite Youth Sports. Part 1: Reaction and Behavior.

PURPOSE: Recent research suggests that stroboscopic training is an effective tool to improve visual and visuomotor performance. However, many studies were limited by small samples, short training interventions, inexperienced athletes, and an exclusive focus on short-term effects. This first part of the study evaluates the short- and long-term effects of stroboscopic training on visuomotor reaction speed in elite athletes. METHODS: Forty-five young elite badminton athletes participated in this study, of which 32 (13.7 yr) were included in the final data analysis. Participants were assigned to an intervention (stroboscopic vision) or control group (normal vision). Both groups performed identical badminton-specific training drills implemented into the regular training schedule. Before and after a 10-wk training period and after a 6-wk retention interval, athletes performed a laboratory reaction test to determine EMG onset and visuomotor reaction time (VMRT). In addition, a field test investigated stroboscopic training effects on the quality of ball-racquet contact and net drop performance. RESULTS: VMRT decreased immediately after stroboscopic training (pre, 251 ms; post, 238 ms; P = 0.005, d = 0.63), and reactions remained significantly faster after the retention interval (retention, 241 ms; P = 0.041, d = 0.50). Analyses on EMG onset data suggested these adaptations were attributable to the premotor rather than the motor time. VMRT remained unchanged in the control group (pre, 252 ms; post, 256; retention, 253 ms; P > 0.99). Field test performance improvements were observed for the quality of ball-racquet contact and net drop performance; however, changes were not different between groups. CONCLUSIONS: Stroboscopic training induced short- and long-term accelerations of visuomotor reaction speed in elite badminton players. Stroboscopic eyewear may be an effective training tool to accelerate visuomotor reactions in highly skilled athletes.

Short- and Long-Term Stroboscopic Training Effects on Visuomotor Performance in Elite Youth Sports. Part 2: Brain-Behavior Mechanisms.

PURPOSE: Stroboscopic training has repeatedly been shown to improve visuomotor abilities. However, although performance improvements were attributed to visual processes, information on the neurophysiological mechanisms is missing. Part 2 of this study investigated the effects of stroboscopic training on neural visual and motor functions and its contribution to training-induced changes in visuomotor reaction time. METHODS: Forty-five young elite badminton athletes participated in this study, of which 32 (age, 13.7 yr) were included in the final data analysis. Participants were assigned to an intervention (stroboscopic vision) or control group (normal vision). Before and after a 10-wk training and after a 6-wk retention period, participants performed visual perception and reaction tasks in response to visual motion stimuli. The N2 and N2-r motion onset visual-evoked potentials, its linear combination (Vlc), and the BA6 negativity potential were determined using a 64-channel EEG. RESULTS: A significant TIME-GROUP effect was observed for the Vlc score (P = 0.019, ηp2 = 0.18), indicating a lower Vlc in the intervention group. However, post hoc tests did not reach significance. Within-subject correlation analyses revealed that changes in reaction speed were related to latency changes in N2 (r = 0.59, P < 0.001), N2-r (r = -0.64, P < 0.001), and the combined Vlc (r = 0.68, P < 0.001). Regression analyses across participants including multiple (N2/N2-r) or single (Vlc) predictors provided an explained variance of >60% (N2/N2-r, r2 = 0.62; Vlc, r2 = 0.64). No training effects or correlations were observed for the BA6 negativity. CONCLUSIONS: The results indicate that faster visuomotor reactions after stroboscopic training are accompanied by accelerated visual perception and processing, whereas motor processes seemed to be unaffected. Stroboscopic training may be promising to specifically address the visual system in visuomotor-demanding sports.

Auditory Information Accelerates the Visuomotor Reaction Speed of Elite Badminton Players in Multisensory Environments.

Although vision is the dominating sensory system in sports, many situations require multisensory integration. Faster processing of auditory information in the brain may facilitate time-critical abilities such as reaction speed however previous research was limited by generic auditory and visual stimuli that did not consider audio-visual characteristics in ecologically valid environments. This study investigated the reaction speed in response to sport-specific monosensory (visual and auditory) and multisensory (audio-visual) stimulation. Neurophysiological analyses identified the neural processes contributing to differences in reaction speed. Nineteen elite badminton players participated in this study. In a first recording phase, the sound profile and shuttle speed of smash and drop strokes were identified on a badminton court using high-speed video cameras and binaural recordings. The speed and sound characteristics were transferred into auditory and visual stimuli and presented in a lab-based experiment, where participants reacted in response to sport-specific monosensory or multisensory stimulation. Auditory signal presentation was delayed by 26 ms to account for realistic audio-visual signal interaction on the court. N1 and N2 event-related potentials as indicators of auditory and visual information perception/processing, respectively were identified using a 64-channel EEG. Despite the 26 ms delay, auditory reactions were significantly faster than visual reactions (236.6 ms vs. 287.7 ms, p < 0.001) but still slower when compared to multisensory stimulation (224.4 ms, p = 0.002). Across conditions response times to smashes were faster when compared to drops (233.2 ms, 265.9 ms, p < 0.001). Faster reactions were paralleled by a lower latency and higher amplitude of the auditory N1 and visual N2 potentials. The results emphasize the potential of auditory information to accelerate the reaction time in sport-specific multisensory situations. This highlights auditory processes as a promising target for training interventions in racquet sports.

Dorsolateral Prefrontal Functional Connectivity Predicts Working Memory Training Gains.

Background: Normal aging is associated with working memory decline. A decrease in working memory performance is associated with age-related changes in functional activation patterns in the dorsolateral prefrontal cortex (DLPFC). Cognitive training can improve cognitive performance in healthy older adults. We implemented a cognitive training study to assess determinants of generalization of training gains to untrained tasks, a key indicator for the effectiveness of cognitive training. We aimed to investigate the association of resting-state functional connectivity (FC) of DLPFC with working memory performance improvement and cognitive gains after the training. Method: A sample of 60 healthy older adults (mean age: 68 years) underwent a 4-week neuropsychological training, entailing a working memory task. Baseline resting-state functional MRI (rs-fMRI) images were acquired in order to investigate the FC of DLPFC. To evaluate training effects, participants underwent a neuropsychological assessment before and after the training. A second follow-up assessment was applied 12 weeks after the training. We used cognitive scores of digit span backward and visual block span backward tasks representing working memory function. The training group was divided into subjects who had and who did not have training gains, which was defined as a higher improvement in working memory tasks than the control group (N = 19). Results: A high FC of DLPFC of the right hemisphere was significantly associated with training gains and performance improvement in the visuospatial task. The maintenance of cognitive gains was restricted to the time period directly after the training. The training group showed performance improvement in the digit span backward task. Conclusion: Functional activation patterns of the DLPFC were associated with the degree of working memory training gains and visuospatial performance improvement. Although improvement through cognitive training and acquisition of training gains are possible in aging, they remain limited.

Exaggerated force production in altered Gz-levels during parabolic flight: the role of computational resources allocation.

The purpose of the present experiment was to examine whether the previously observed exaggerated isometric force production in changed-Gz during parabolic flight (Mierau et al. 2008) can be explained by a higher computational demand and, thus, inadequate allocation of the brain's computational resources to the task. Subjects (n = 12) were tested during the micro-Gz, high-Gz and normal-Gz episodes of parabolic flight. They produced isometric forces of different magnitudes and directions, according to visually prescribed vectors with their right, dominant hand and performed a choice reaction-time task with their left hand. Tasks were performed either separately (single-task) or simultaneously (dual-task). Dual-task interference was present for both tasks, indicating that each task was resources-demanding. However, this interference remained unaffected by the Gz-level. It was concluded that exaggerated force production in changed-Gz is probably not related to inadequate allocation of the brain's computational resources to the force production task. Statement of Relevance: The present study shows that deficient motor performance in changed-Gz environments (both micro-Gz and high-Gz) is not necessarily related to inadequate computational resources allocation, as was suggested in some previous studies. This finding is of great relevance not only for fundamental research, but also for the training and safety of humans operating in changed-Gz environments, such as astronauts and jet pilots.

The Impact of Age on the Association Between Physical Activity and White Matter Integrity in Cognitively Healthy Older Adults.

Cognition emerges from coordinated processing among distributed cortical brain regions, enabled through interconnected white matter networks. Cortical disconnection caused by age-related decline in white matter integrity (WMI) is likely to contribute to age-related cognitive decline. Physical activity (PA) has been suggested to have beneficial effects on white matter structure. However, its potential to counteract age-related decline in WMI is not yet well established. The present explorative study analyzed if PA was associated with WMI in cognitively healthy older adults and if this association was modulated by age. Forty-four cognitively healthy older individuals (aged 60-88 years) with diffusion-tensor imaging (DTI) and PA measurements were included from the AgeGain study. Voxelwise analysis using Tract-Based Spatial Statistics (TBSS) demonstrated that PA was associated with WMI in older adults. However, results emphasized that this association was restricted to high age. The association between PA and WMI was found in widespread white matter regions suggesting a global rather than a regional effect. Supplementary analyses demonstrated an association between the integrity of these regions and the performance in memory [verbal learning and memory test (VLMT)] and executive functioning (Tower of London).Results of the present explorative study support the assumption that PA is associated with WMI in older adults. However, results emphasize that this association is restricted to high age. Since cognitive decline in the elderly is typically most pronounced in later stages of aging, PA qualifies as a promising tool to foster resilience against age-related cognitive decline, via the preservation of the integrity of the brains WM.

Improved sensorimotor adaptation after exhaustive exercise is accompanied by altered brain activity.

Acute exercise has been shown to exhibit different effects on human sensorimotor behavior; however, the causes and mechanisms of the responses are often not clear. The primary aim of the present study was to determine the effects of incremental running until exhaustion on sensorimotor performance and adaptation in a tracking task. Subjects were randomly assigned to a running group (RG), a tracking group (TG), or a running followed by tracking group (RTG), with 10 subjects assigned to each group. Treadmill running velocity was initially set at 2.0 m s(-1), increasing by 0.5 m s(-1) every 5 min until exhaustion. Tracking consisted of 35 episodes (each 40 s) where the subjects' task was to track a visual target on a computer screen while the visual feedback was veridical (performance) or left-right reversed (adaptation). Resting electroencephalographic (EEG) activity was recorded before and after each experimental condition (running, tracking, rest). Tracking performance and the final amount of adaptation did not differ between groups. However, task adaptation was significantly faster in RTG compared to TG. In addition, increased alpha and beta power were observed following tracking in TG but not RTG although exhaustive running failed to induce significant changes in these frequency bands. Our results suggest that exhaustive running can facilitate adaptation processes in a manual tracking task. Attenuated cortical activation following tracking in the exercise condition was interpreted to indicate cortical efficiency and exercise-induced facilitation of selective central processes during actual task demands.