Andreas Mierau

EEG activity and mood in health orientated runners after different exercise intensities.

An increasing number of studies within the recent years connected physical exercise with changes in brain cortical activity. Most of this data (1) refers to aerobic exercise and (2) does not correlate to psychological parameters although it is well known that exercise has a positive effect on mood. In times where health activities play a major role it is increasingly necessary to connect somato-physiological and somatopsychological components of physical activity. This study aimed to find changes in EEG activity and mood after low, preferred and high intensity running. EEG and actual state of mood were recorded before and after exercise. Results showed an effect for the preferred and high intensity velocity in both, EEG and mood. As only the higher frequency areas N18 Hz showed persisting decreases post-exercise we concluded that this might be a sign of outlasting effects of exercise on brain cortical activity which may have influences on general well-being. We could also show that there is a clear relationship between EEG activity and mood reflecting a basic principle of cortical excitation.

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 individuals 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.

Brain and exercise : a first approach using electrotomography

PURPOSE The impact of exercise on brain function has gained broad interest. Because hemodynamic and imaging studies are difficult to perform during and after exercise, electroencephalography (EEG) is often the method of choice. Within this study, we aimed 1) to extend prior work examining changes in scalp-recorded brain electrical activity associated with exercise and 2) to use a distributed source localization algorithm (standardized low-resolution brain electromagnetic tomography [sLORETA]) to model the probable neural sources of changes in EEG activity after exercise. METHODS Electrocortical activity of 22 recreational runners (21-45 yr) was recorded before and after exhaustive treadmill ergometry. Data were analyzed using sLORETA. RESULTS There was an increase in alpha-1 activity (7.5-10 Hz) immediately after exercise, which was localized to the left frontal gyrus (Brodmann area 8). This finding is consistent with alterations in emotional processing. Fifteen minutes after exercise, a decrease in alpha-2 (10-12.5 Hz), beta-1 (12.5-18 Hz), and gamma activities (35-48 Hz) was observed in Brodmann areas 18 and 20-22, which are well known to be involved in language processing. CONCLUSION This study demonstrates that sLORETA is a robust method that allows brain activity maps to be generated from standardized EEG recordings following exercise.

Cortical processes associated with continuous balance control as revealed by EEG spectral power.

Balance is a crucial component in numerous every day activities such as locomotion. Previous research has reported distinct changes in cortical theta activity during transient balance instability. However, there remains little understanding of the neural mechanisms underlying continuous balance control. This study aimed to investigate cortical theta activity during varying difficulties of continuous balance tasks, as well as examining the relationship between theta activity and balance performance. 37 subjects completed nine balance tasks with different levels of surface stability and base of support. Throughout the balancing task, electroencephalogram (EEG) was recorded from 32 scalp locations. ICA-based artifact rejection was applied and spectral power was analyzed in the theta frequency band. Theta power increased in the frontal, central, and parietal regions of the cortex when balance tasks became more challenging. In addition, fronto-central and centro-parietal theta power correlated with balance performance. This study demonstrates the involvement of the cerebral cortex in maintaining upright posture during continuous balance tasks. Specifically, the results emphasize the important role of frontal and parietal theta oscillations in balance control.

Increased brain cortical activity during parabolic flights has no influence on a motor tracking task

Previous studies showed that changing forces of gravity as they typically occur during parabolic flights might be responsible for adaptional processes of the CNS. However, until now it has not been differentiated between primary influences of weightlessness and secondary influences due to psycho-physiological factors (e.g., physical or mental strain). With the aim of detecting parabolic flight related changes in central cortical activity, a resting EEG was deduced in 16 subjects before, during and after parabolic flights. After subdividing EEG into α-, β-,δ- and θ-wave bands, an increase in β-power was noticeable inflight, whereas α1-power was increased postflight. No changes could be observed for the control group. To control possible effects of cortical activation, a manual tracking task with mirror inversion was performed during either the phase of weightlessness or during the normal gravity phase of a parabolic flight. No differences in performance nor in adaptation could be observed between both groups. A third group, performing under normal and stress-free conditions in a lab showed similar tracking values. We assume that the specific increase in brain activity is a sign of an increase in arousal inflight. This does support previous assumptions of non-specific stressors during parabolic flights and has to be considered as a relevant factor for experiments on central nerve adaptation. Although no influences of stress and/or weightlessness on motor perfromance and adaptation could be observed, we suggest that an “inflight” control group seems to be more adequate than a laboratory control group to investigate gravity-dependent changes in motor control.

Post-chemotherapy cognitive impairment in patients with B-cell non-Hodgkin lymphoma: a first comprehensive approach to determine cognitive impairments after treatment with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone or rituximab and bendamustine

Abstract To assess the effects of chemoimmunotherapy on post-chemotherapy cognitive impairments (PCCI) in patients with B-cell non-Hodgkin lymphoma (NHL), we used objective and subjective measures of cognitive functions in combination with serum parameters and neuroelectric recordings. Self-perceived status of cognition, fatigue and emotional functioning were reduced in patients (n = 30) compared to healthy controls (n = 10). Cognitive performance was impaired in patients with NHL compared to controls and a norm sample (n = 1179). PCCI was more severe in patients treated with rituximab and bendamustine (BR) than in patients who received R in combination with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) polychemotherapy (R-CHOP). Individual alpha peak frequency and serum brain-derived neurotrophic factor (BDNF) levels in patients with NHL correlated with accuracy in the objective cognition test. Higher serum interleukin-6 (IL-6) concentrations were associated with higher fatigue levels. Patients with NHL and especially those who were treated with BR were affected by PCCI. BDNF and IL-6 might be involved in the pathogenesis of PCCI and fatigue.

Changes in cortical activity associated with adaptive behavior during repeated balance perturbation of unpredictable timing

The compensation for a sudden balance perturbation, unpracticed and unpredictable in timing and magnitude is accompanied by pronounced postural instability that is suggested to be causal to falls. However, subsequent presentations of an identical perturbation are characterized by a marked decrease of the amplitude of postural reactions; a phenomenon called adaptation or habituation. This study aimed to identify cortical characteristics associated with adaptive behavior during repetitive balance perturbations based on single-trial analyses of the P1 and N1 perturbation-evoked potentials. Thirty-seven young men were exposed to ten transient balance perturbations while balancing on the dominant leg. Thirty two-channel electroencephalography (EEG), surface electromyography (EMG) of the ankle plantar flexor muscles and postural sway (i.e., Euclidean distance of the supporting platform) were recorded simultaneously. The P1 and N1 potentials were localized and the amplitude/latency was analyzed trial by trial. The best match sources for P1 and N1 potentials were located in the parietal (Brodmann area (BA) 5) and midline fronto-central cortex (BA 6), respectively. The amplitude and latency of the P1 potential remained unchanged over trials. In contrast, a significant adaptation of the N1 amplitude was observed. Similar adaptation effects were found with regard to postural sway and ankle plantarflexors EMG activity of the non-dominant (free) leg; i.e., an indicator for reduced muscular co-contraction and/or less temporary bipedal stance to regain stability. Significant but weak correlations were found between N1 amplitude and postural sway as well as EMG activity. These results highlight the important role of the midline fronto-central cortex for adaptive behavior associated with balance control.

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

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.

Human-Robot Interaction: Does Robotic Guidance Force Affect Gait-Related Brain Dynamics during Robot-Assisted Treadmill Walking?

In order to determine optimal training parameters for robot-assisted treadmill walking, it is essential to understand how a robotic device interacts with its wearer, and thus, how parameter settings of the device affect locomotor control. The aim of this study was to assess the effect of different levels of guidance force during robot-assisted treadmill walking on cortical activity. Eighteen healthy subjects walked at 2 km.h-1 on a treadmill with and without assistance of the Lokomat robotic gait orthosis. Event-related spectral perturbations and changes in power spectral density were investigated during unassisted treadmill walking as well as during robot-assisted treadmill walking at 30%, 60% and 100% guidance force (with 0% body weight support). Clustering of independent components revealed three clusters of activity in the sensorimotor cortex during treadmill walking and robot-assisted treadmill walking in healthy subjects. These clusters demonstrated gait-related spectral modulations in the mu, beta and low gamma bands over the sensorimotor cortex related to specific phases of the gait cycle. Moreover, mu and beta rhythms were suppressed in the right primary sensory cortex during treadmill walking compared to robot-assisted treadmill walking with 100% guidance force, indicating significantly larger involvement of the sensorimotor area during treadmill walking compared to robot-assisted treadmill walking. Only marginal differences in the spectral power of the mu, beta and low gamma bands could be identified between robot-assisted treadmill walking with different levels of guidance force. From these results it can be concluded that a high level of guidance force (i.e., 100% guidance force) and thus a less active participation during locomotion should be avoided during robot-assisted treadmill walking. This will optimize the involvement of the sensorimotor cortex which is known to be crucial for motor learning.

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

ABSTRACT 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), Youngs 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. Highlighted Article: The stiffness of the aging Achilles tendon increases after 14 weeks of mechanical loading exercise by changing its material and dimensional properties, whereas continuing exercise causes no further adaptive changes.