Exercise-Induced Changes of Multimodal Interactions Within the Autonomic Nervous Network

Physical exercise has been shown to modulate activity within the autonomic nervous system (ANS). Considering physical exercise as a holistic stimulus on the nervous system and specifically the ANS, uni- and multimodal analysis tools were applied to characterize centrally driven interactions and control of ANS functions. Nineteen young and physically active participants performed treadmill tests at individually determined moderate and high intensities. Continuous electrodermal activity (EDA), heart rate (HR), and skin temperature at wrist (Temp) were recorded by wireless multisensor devices (Empatica® E4, Milan, Italy) before and 30 min after exercise. Artifact-free continuous 3 min intervals were analyzed. For unimodal analysis, mean values were calculated, for bimodal and multimodal analysis canonical correlation analysis (CCA) was performed. Unimodal results indicate that physical exercise affects ANS activity. More specifically, Temp increased due to physical activity (moderate intensity: from 34.15°C to 35.34°C and high intensity: from 34.11°C to 35.09°C). HR increased more for the high (from 60.76 bpm to 79.89 bpm) than for the moderate (from 64.81 bpm to 70.83 bpm) intensity. EDA was higher for the high (pre: 8.06 μS and post: 9.37 μS) than for the moderate (pre: 4.31 μS and post: 3.91 μS) intensity. Bimodal analyses revealed high variations in correlations before exercise. The overall correlation coefficient showed varying correlations in pretest measures for all modality pairs (EDA-HR, HR-Temp, Temp-EDA at moderate: 0.831, 0.998, 0.921 and high: 0.706, 0, 0.578). After exercising at moderate intensity coefficients changed little (0.828, 0.744, 0.994), but increased substantially for all modality pairs after exercising at high intensity (0.976, 0.898, 0.926). Multimodal analysis confirmed bimodal results. Exercise-induced changes in ANS activity can be found in multiple ANS modalities as well as in their interactions. Those changes are intensity-specific: with higher intensity the interactions increase. Canonical correlations between different ANS modalities may therefore offer a feasible approach to determine exercise induced modulations of ANS activity

Age-related changes in force control under different task contexts

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Effects of age and fine motor expertise on the bilateral deficit in force initiation

Performance of a task carried out with two hands separately is better than the performance of the same task done with both hands at the same time. This so-called bilateral deficit may be reduced or counteracted by long-term practice. Little is known about age-related changes. We examined age- and expertise-related differences in the bilateral deficit in force initiation. Participants performed static and dynamic force modulation tasks either with the right and left hand separately or both hands simultaneously. In order to examine age-related differences, we compared novices of fine motor control (service employees) from three age groups, covering the working age (young n = 13, early middle-aged n = 10 and late middle-aged n = 12). To assess the influence of expertise, we considered precision mechanics as experts in fine motor control. To ensure the acquisition of expertise, only early middle-aged (n = 10) and late middle-aged (n = 14) experts were recruited. Regardless of the task, bimanual force initiation was slower than unimanual force initiation. This bilateral deficit was (1) more pronounced in the static than in the dynamic task, (2) higher in early and late middle-aged than in younger novices, and (3) lower in experts as compared to novices. Based on our results, we assume both interhemispheric inhibition and division of attention to contribute to the bilateral deficit and the expertise- and age-related differences, respectively. The results are promising for the possibility to overcome constraints of bilateral hand movements by long-term practice

Age-related changes in finger-force-control is characterized by force production with lower amplitudes

It has been repeatedly shown that precise finger force control declines with age. The tasks and evaluation parameters used to reveal age-related differences vary between studies. In order to examine effects of task characteristics, young adults (18-25 years) and late middle-aged adults (55-65 years) performed precision grip tasks with varying speed and force requirements. Different outcome variables were used to evaluate age-related differences. Age-related differences were confirmed for performance accuracy (TWR) and variability (relative root mean square error, rRMSE). The task characteristics, however, influenced accuracy and variability in both age groups: Force modulation performance at higher speed was poorer than at lower speed and at fixed force levels than at force levels adjusted to the individual maximum forces. This effect tended to be stronger for older participants for the rRMSE. A curve fit confirmed the age-related differences for both spatial force tracking parameters (amplitude and intercept) and for one temporal parameter (phase shift), but not for the temporal parameter frequency. Additionally, matching the timing parameters of the sine wave seemed to be more important than matching the spatial parameters in both young adults and late middle-aged adults. However, the effect was stronger for the group of late middle-aged, even though maximum voluntary contraction was not significantly different between groups. Our data indicate that changes in the processing of fine motor control tasks with increasing age are caused by difficulties of late middle-aged adults to produce a predefined amount of force in a short time

The role of eye movements in motor sequence learning

International audienceAn experiment that utilized a 16-element movement sequence was designed to determine the impact of eye movements on sequence learning. The participants were randomly assigned to two experimental groups: a group that was permitted to use eye movements (FREE) and a second group (FIX) that was instructed to fixate on a marker during acquisition (ACQ). A retention test (RET) was designed to provide a measure of learning, and two transfer tests were designed to determine the extent to which eye movements influenced sequence learning. The results demonstrated that both groups decreased the response time to produce the sequence, but the participants in the FREE group performed the sequence more quickly than participants of the FIX group during the ACQ, RET and the two transfer tests. Furthermore, continuous visual control of response execution was reduced over the course of learning. The results of the transfer tests indicated that oculomotor information regarding the sequence can be stored in memory and enhances response production

Touch perception throughout working life: Effects of age and expertise

Fine motor skills including precise tactile and haptic perception are essential to the manipulation of objects. With increasing age, one's perception decreases; however, little is known about the state of touch perception in middle-aged adults. This study investigated the extent to which the decline in touch perception affects adults throughout their working life. In addition, the influence of work-related expertise on tactile and haptic perception was examined in an attempt to determine whether expertise, in the form of the frequent use of the fingers, affects perception and counters age-related losses. The study was conducted with subjects from three age groups (18-25, 34-46, and 54-65 years) with two levels of expertise. Expertise was classified by the subjects' occupations. Five sensory tasks of touch perception were conducted. The results confirmed age-related changes in tactile perception over the span of one's working life. Older workers were proven to have lower tactile performance than younger adults. However, middle-aged workers were hardly affected by the perception losses and did not differ significantly from younger adults. Work-related expertise was not proven to either affect tactile and haptic perception or counteract age-related declines. We conclude that the age-related decline gets steeper in the late working life and that specific work-related expertise does not lead to generally improved touch perception that would result in lower thresholds and improved performance in non-expertise specific tasks

The influence of age and work-related expertise on fine motor control

Age-related decline of fine motor control commences even in middle adulthood. Less is known, however, whether age-related changes can be postponed through continuous practice. In this study we tested how age and professional expertise influence fine motor control in middle-aged adults. Forty-eight right-handed novices and experts (35 to 65 years) performed submaximal precision grip force modulation tasks with index or middle finger opposing the thumb, either with the right hand or the left hand. Novices revealed expected age-related differences in all performance measures (force initialization, mean applied force, variability), whereas experts outperformed novices in all outcome measures. Expertise seems to contribute to maintaining manual skills into older age, as indicated by the age and expertise interaction for the force initialization

The association between physical activity and attentional control in younger and older middle-aged adults: an ERP study.

This study investigates the association between physical activity level and attentional control in a group of younger and older middle-aged adults (MA). Participants performed a Flanker task; two types of conflict were analyzed: response and perceptual conflict. For perceptual conflict, behavioral findings suggest that, irrespective of age, physical activity is positively associated with attentional control. For response conflicts, only highly active younger MA showed better attentional control, indicated by increased amplitudes of the event related potential N2 and reduced interference costs by distracting information. Physical activity did not modulate P3 amplitudes. The findings are discussed with respect to physical activity as functional approach to maintain cognitive functioning across the lifespan