Handgrip Task Research Articles

The modality effect of ego depletion: Auditory task modality reduces egodepletion.

An initial act of self-control that impairs subsequent acts of self-control is called ego depletion. The ego depletion phenomenon has been observed consistently. The modality effect refers to the effect of the presentation modality on the processing of stimuli. The modality effect was also robustly found in a large body of research. However, no study to date has examined the modality effects of ego depletion. This issue was addressed in the current study. In Experiment 1, after all participants completed a handgrip task, one group's participants completed a visual attention regulation task and the other group's participants completed an auditory attention regulation task, and then all participants again completed a handgrip task. The ego depletion phenomenon was observed in both the visual and the auditory attention regulation task. Moreover, participants who completed the visual task performed worse on the handgrip task than participants who completed the auditory task, which indicated that there was high ego depletion in the visual task condition. In Experiment 2, participants completed an initial task that either did or did not deplete self-control resources, and then they completed a second visual or auditory attention control task. The results indicated that depleted participants performed better on the auditory attention control task than the visual attention control task. These findings suggest that altering task modality may reduce ego depletion.

The neural mechanisms of re-experiencing physical fatigue sensation: a magnetoencephalography study.

It has been hypothesized that fatigue sensation impairs the ability and efficiency to perform activities and can be a cause of fatigue itself. As such, it is important to clarify the neural mechanisms of fatigue sensation. The re-experiencing of mental fatigue sensation involves brain regions including Brodmann's area (BA) 40, BA 39, and the pulvinar nucleus. In the present study, we examined neural activity caused by re-experiencing a physical fatigue sensation that had been experienced. Fifteen healthy male volunteers participated in fatigue and control experiments in a crossover fashion. In the fatigue experiment, participants performed a handgrip task for 10min to induce a physical fatigue sensation and then re-experienced the physical fatigue sensation during magnetoencephalography (MEG) session. In the control experiment, they did not perform the handgrip task but re-experienced the sensation without physical fatigue in an MEG session. Neural activity related to re-experiencing physical fatigue sensations of the right hand (right condition), left hand (left condition), and related to listening to the auditory cues (sound condition) was assessed using spatial filtering analyses of the MEG data. Changes in oscillatory band power in some brain regions, including BA 40, were common between the right and left conditions. A part of the neural activity related to the re-experiencing physical fatigue sensation, such as the decrease in alpha (8-13Hz) band power in the BA 40, was also observed in the sound condition. These findings may help to understand the neural mechanisms related to intentionally and unintentionally re-experiencing physical fatigue sensation.

Computational modelling of movement-related beta-oscillatory dynamics in human motor cortex

Oscillatory activity in the beta range, in human primary motor cortex (M1), shows interesting dynamics that are tied to behaviour and change systematically in disease. To investigate the pathophysiology underlying these changes, we must first understand how changes in beta activity are caused in healthy subjects. We therefore adapted a canonical (repeatable) microcircuit model used in dynamic causal modelling (DCM) previously used to model induced responses in visual cortex. We adapted this model to accommodate cytoarchitectural differences between visual and motor cortex. Using biologically plausible connections, we used Bayesian model selection to identify the best model of measured MEG data from 11 young healthy participants, performing a simple handgrip task. We found that the canonical M1 model had substantially more model evidence than the generic canonical microcircuit model when explaining measured MEG data. The canonical M1 model reproduced measured dynamics in humans at rest, in a manner consistent with equivalent studies performed in mice. Furthermore, the changes in excitability (self-inhibition) necessary to explain beta suppression during handgrip were consistent with the attenuation of sensory precision implied by predictive coding. These results establish the face validity of a model that can be used to explore the laminar interactions that underlie beta-oscillatory dynamics in humans in vivo. Our canonical M1 model may be useful for characterising the synaptic mechanisms that mediate pathophysiological beta dynamics associated with movement disorders, such as stroke or Parkinson's disease.

Positive Affect and Cognitive Restoration: Investigating the Role of Valence and Arousal.

Positive moods are thought to restore self-control resources following depletion. However, it is not well understood whether this effect is due to affective valence (pleasantness), arousal (activation), or a combination of both. Across four studies, we set out to investigate the role of positive moods on cognitive and behavioral measures of self-regulation in an ego-depletion paradigm. In studies 1 and 2, we independently manipulated affective valence and arousal and assessed self-regulation with a Stroop task. Results did not suggest a restorative effect of either on cognitive resources. In study 3, we employed both behavioral (the ‘handgrip task’) and cognitive (Stroop) assessments of self-regulation. Again, no significant effect of mood was observed on the Stroop task. Additionally, participants did not persist significantly longer on the handgrip task following a positive mood induction. Finally, in study 4, high vs. low states of arousal were manipulated and self-regulation was assessed via pre- and post-manipulation Stroop performance. In study 4, Stroop performance improved slightly more across time points for those in the high arousal condition than for those in the low arousal condition. Therefore, across four studies, we failed to find a consistent pattern of results suggesting that positive moods restore cognitive resources.

Evidence against the primacy of energy conservation: Exerted force in possible and impossible handgrip tasks.

Evidence against the primacy of energy conservation: Exerted force in possible and impossible handgrip tasks.

High frequency activation data used to validate localization of cortical electrodes during surgery for deep brain stimulation.

Movement related synchronization of high frequency activity (HFA, 76–100 Hz) is a somatotopic process with spectral power changes occurring during movement in the sensorimotor cortex (Miller et al., 2007) [1]. These features allowed movement-related changes in HFA to be used to functionally validate the estimations of subdural electrode locations, which may be placed temporarily for research in deep brain stimulation surgery, using the novel tool described in Randazzo et al. (2015) [2]. We recorded electrocorticography (ECoG) signals and localized electrodes in the region of the sensorimotor cortex during an externally cued hand grip task in 8 subjects. Movement related HFA was determined for each trial by comparing HFA spectral power during movement epochs to pre-movement baseline epochs. Significant movement related HFA was found to be focal in time and space, occurring only during movement and only in a subset of electrodes localized to the pre- and post-central gyri near the hand knob. To further demonstrate the use of movement related HFA to aid electrode localization, we provide a sample of the electrode localization tool, with data loaded to allow readers to map movement related HFA onto the cortical surface of a sample patient.

CONTROLLING ABSOLUTE FREQUENCY OF FEEDBACK IN A SELF-CONTROLLED SITUATION ENHANCES MOTOR LEARNING.

The guidance hypothesis suggested that excessive extrinsic feedback facilitates motor performance but blocks the processing of intrinsic information. The present study tested the tenet of guidance hypothesis in self-controlled feedback by controlling the feedback frequency. The motor learning effect of limiting absolute feedback frequency was examined. Thirty-six participants (25 men, 11 women; M age=25.1 yr., SD=2.2) practiced a hand-grip force control task on a dynamometer by the non-dominant hand with varying amounts of feedback. They were randomly assigned to: (a) Self-controlled, (b) Yoked with self-controlled, and (c) Limited self-controlled conditions. In acquisition, two-way analysis of variance indicated significantly lower absolute error in both the yoked and limited self-controlled groups than the self-controlled group. The effect size of absolute error between trials with feedback and without feedback in the limited self-controlled condition was larger than that of the self-controlled condition. In the retention and transfer tests, the Limited self-controlled feedback group had significantly lower absolute error than the other two groups. The results indicated an increased motor learning effect of limiting absolute frequency of feedback in the self-controlled condition.

Muscular forearm activation in hand-grip tasks with superimposition of mechanical vibrations

The purpose of this paper is to evaluate the muscular activation of the forearm, with or without vibration stimuli at different frequencies while performing a grip tasks of 45s at various level of exerted force. In 16 individuals, 9 females and 7 males, the surface electromyogram (EMG) of extensor carpi radialis longus and the flexor carpi ulnari muscles were assessed. At a short latency from onset EMG, RMS and the level of MU synchronization were assessed to evaluate the muscular adaptations. Whilst a trend of decay of EMG Median frequency (MDFd) was employed as an index of muscular fatigue. Muscular tasks consists of the grip of an instrumented handle at a force level of 20%, 30%, 40%, 60% of the maximum voluntary force. Vibration was supplied by a shaker to the hand in mono-frequential waves at 20, 30, 33 and 40Hz. In relation to EMG, RMS and MU synchronization, the muscular activation does not seem to change with the superimposition of the mechanical vibrations, on the contrary a lower MDFd was observed at 33Hz than in absence of vibration. This suggests an early muscular fatigue induced by vibration due to the fact that 33Hz is a resonance frequency for the hand-arm system.

Ipsi- and contralateral frontal cortex oxygenation during handgrip task does not follow decrease on maximal force output.

The effect of fatiguing exercise on the ipsi- and contralateral frontal cortex has not been fully clarified. The purpose of this study was to investigate by near-infrared spectroscopy (NIRS) the frontal cortex oxygenation response to a prolonged fatiguing repetitive handgrip exercise performed at maximal voluntary contraction. It was found a significant oxyhemoglobin concentration ([HbO2]) increase (p < 0.05), accompanied by a smaller and delayed deoxyhemoglobin concentration ([Hb]) decrease (p < 0.05), in both hemispheres. Then, it was indicated higher delayed oxygenation in ipsilateral oxygenation compared to contralateral oxygenation. These results provide further evidence that the complemental interaction between the ipsilateral and contralateral cortex during the fatiguing maximal exercise.

Humility facilitates higher self-control

Prior evidence and existing theories imply that humility engenders intra- and inter-personal attributes that facilitate self-regulatory abilities. Four experiments were conducted to test the hypothesis that humility predicts enhanced self-control. Participants who recalled humility experiences were found to be better able at sustaining their physical stamina in a handgrip task (Studies 1 and 4), resisting indulgence in chocolates (Study 2), and persevering in a frustrating tracing task (Study 3) than those who recalled neutral experiences. Studies 3 and 4 demonstrated that the effect of humility was distinct from that of self-esteem, which did not affect self-control. Study 2 ruled out two alternative hypotheses concerning achievement and compliance motives. We discuss how the findings might relate to outcomes associated with humility as evidenced in past studies.

Complementary activation of the ipsilateral primary motor cortex during a sustained handgrip task.

Near-infrared spectroscopy (NIRS) can be used to examine bilateral motor cortex activation during a sustained motor task in brain areas where increased oxygenation reflects cortical activation. This study examines the time course of activation of the bilateral motor cortex during a moderate-intensity handgrip task. Ten healthy right-handed male subjects participated in this study. Functional NIRS probes were placed over the cortex to measure motor cortical activations while the subjects performed a 180-s handgrip task incrementally [30-60% of the maximal voluntary contraction (MVC) at 0.17% increase/s] Contralateral primary motor cortex (ContraM1) oxygenation values significantly increased from baseline between 40 and 120 s after the start of the motor task (p < 0.05). Moreover, the ipsilateral primary motor cortex (IpsiM1) oxygenation values significantly increased from baseline between 140 and 180 s after the start of the motor task (p < 0.05). IpsiM1 oxygenation gradually increased from 140 to 180 s, whereas ContraM1 oxygenation gradually decreased from 120 to 180 s after the start of the motor task. These results suggest that the complementary functions of IpsiM1 become activated in response to the working of the ContraM1 during a continuous handgrip task.

P106. Brain connectivity in a simple motor task characterized by dynamic causal modeling of EEG FMRI signal

Introduction Dynamic causal modeling (DCM) based on functional magnetic resonance imaging (FMRI) and magneto-/electroencephalographic (MEEG) data has increasingly extended the understanding of intrinsic brain network dynamics in a variety of functional systems (Friston et al., Curr Opin Neurobiol, 2013). In the motor system, several studies have used DCM to detect causal information flow from secondary to primary motor areas during simple movements and bimanual coordination (Grefkes et al., Neuroimage, 2008). There is also evidence for non-linear cross-frequency interactions among motor areas (Chen et al., J of Neuroscience, 2010; Herz et al., Neuroimage, 2012). As such, data based on MEEG and FMRI provide complementary and synergistic insights into the dynamics of motor networks due to the higher spatial resolution of brain activity by FMRI versus the frequency-resolved coupling revealed by MEEG. A study combining FMRI- and EEG-based DCM for induced responses (DCM-IR) using the same task in the same participants to directly compare network architectures deriving from BOLD response and spectral neuroelectric dynamics has not been conducted so far. Specifically, such an approach is of interest as both modalities share principal similarities in the formulation of the DCM. We hypothesized that DCM based on induced responses and the BOLD-signal would reveal a similar network architecture. Methods To test this, we measured 14 young healthy individuals during a simple isometric hand grip task using FMRI and EEG separately, set up a common model space of six equally plausible models and modeled the coupling parameters within a core motor network during the right hand grip. Results Bayesian Model Selection revealed strongest evidence for a fully connected model in DCM for FMRI and a sparsely connected model in DCM-IR, comparing the individual interregional coupling parameters revealed interesting similarities: First, both modalities showed a significant grip-related increase in facilitatory coupling from the left SMA onto the left M1. Second, the left PMv also exerted a positive coupling onto the left M1 with a significant result for DCM-IR and a trend of significance for DCM for fMRI. Frequency-resolved coupling showed that the information flow from SMA to M1 was a linear alpha to alpha interaction but also a nonlinear cross-frequency interaction between faster oscillations in SMA (18–25 Hz) and full range alpha to beta (9–22 Hz) in left M1. Coupling between PMv and M1 was found from upper alpha (10–13 Hz) to lower beta (14–22 Hz). Conclusion The strategy of informing EEG source space configurations with FMRI location priors, cross-validating basic connectivity maps and then looking at the details of frequency coding allows for a deeper insight into the motor network architecture in the human brain. These results thus undermine the importance of these functional connections and validate the methodological approach of DCM to explore network architecture. Furthermore, extending findings from previous studies showing a covariation of the BOLD-signal and alpha/beta band power (Ritter et al., Human Brain Mapping, 2009; Yuan et al., Neuroimage, 2010), we here present evidence that these two signals not only share similarities in local activation patterns but also in the connectivity domain.

Investigating the modulation of brain activity associated with handgrip force and fatigue.

To investigate the effect of force level and fatigue on brain activity during handgrip tasks. Electroencephalography (EEG) signals were recorded from eleven healthy male subjects when they performed 25%, 50% and 75% maximal voluntary contraction (MVC), and were in fatigue state. EEG powers in different handgrip tasks were analyzed in the frequency domain and time domain respectively. The EEG power at 25%MVC was significantly lower than that at 75%MVC in gamma band (p< 0.05) for electrode C3, C4, Cz, Pz and Fz. EEG power at 25%MVC was also significantly lower than that at 75%MVC in beta band (p< 0.05) for electrode C3. However, the handgrip force level and fatigue did not affect the EEG powers for the other frequencies and electrodes (p> 0.05). The results suggest that handgrip force level may modulate the brain activity in certain frequency bands and cortical regions. EEG power is a useful tool to characterize the motor state.

Muscle Fatigue in the Three Heads of the Triceps Brachii During a Controlled Forceful Hand Grip Task with Full Elbow Extension Using Surface Electromyography.

The objective of the present study was to investigate the time to fatigue and compare the fatiguing condition among the three heads of the triceps brachii muscle using surface electromyography during an isometric contraction of a controlled forceful hand grip task with full elbow extension. Eighteen healthy subjects concurrently performed a single 90 s isometric contraction of a controlled forceful hand grip task and full elbow extension. Surface electromyographic signals from the lateral, long and medial heads of the triceps brachii muscle were recorded during the task for each subject. The changes in muscle activity among the three heads of triceps brachii were measured by the root mean square values for every 5 s period throughout the total contraction period. The root mean square values were then analysed to determine the fatiguing condition for the heads of triceps brachii muscle. Muscle fatigue in the long, lateral, and medial heads of the triceps brachii started at 40 s, 50 s, and 65 s during the prolonged contraction, respectively. The highest fatiguing rate was observed in the long head (slope = −2.863), followed by the medial head (slope = −2.412) and the lateral head (slope = −1.877) of the triceps brachii muscle. The results of the present study concurs with previous findings that the three heads of the triceps brachii muscle do not work as a single unit, and the fiber type/composition is different among the three heads.

Comparison of two isometric handgrip protocols on sympathetic arousal in women

Isometric handgrip is commonly used in stress research because the task reliably increases sympathetic arousal. Various handgrip protocols have been used; they vary in handgrip strength, duration of grip, and the number of cycles of handgrip and rest. However, most protocols require the calibration of a maximum voluntary contraction (MVC) prior to the handgrip task, which is not always convenient (i.e., in a functional magnetic resonance imaging study). Here, we wanted to test whether two handgrip protocols with different strength, duration and cycle protocols would reliably elicit sympathetic arousal in the absence of calibrating an MVC. Sixty-two healthy naturally cycling women and women on hormonal contraception participated in one of the two isometric handgrip protocols using a hand therapy ball of medium resistance. Women completed one of the following handgrip protocols: 1) 30% of a perceived maximum voluntary contraction for 3min or 2) 3cycles of maximum voluntary contraction for 18s with a one minute rest in between. All handgrip blocks were counterbalanced with a control condition. Sympathetic arousal was measured throughout the session via pupil diameter changes and salivary alpha-amylase. Results indicate that in the absence of calibrating an MVC, the handgrip tasks elicited different changes in sympathetic arousal. Pupil dilation responses increased significantly in the handgrip versus control blocks only in participants in the 18-s protocol. Additionally, more participants exhibited a salivary alpha-amylase response to the handgrip block in the 18-s condition compared to the 3-min condition. Thus, these results suggest that neuroimaging and behavioral studies with isometric handgrip should be able to successfully induce sympathetic nervous activity with the 18-s paradigm, regardless of the handgrip device and the ability to calibrate an MVC.

Influence of internal carotid artery stenosis, blood pressure, glycated hemoglobin, and hemoglobin level on fMRI signals of stroke patients

Objectives:To identify the effect of internal carotid artery (ICA) stenosis, blood pressure (BP), glycated hemoglobin (HbA1c), and hemoglobin level on blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals in stroke patients.Methods:A total of 18 stroke patients with acute cerebral infarction (13 males and 5 females) and 13 age-matched healthy controls (5 males and 8 females) were recruited. Among 18 stroke patients, 8 had significant ICA stenosis (>50%) and 10 had nonsignificant ICA stenosis (<50%). During handgrip task, stroke patients and normal controls were allowed to use their hands coincided with infarction and right hands, respectively.Results:The mean BOLD signals in patients with significant ICA stenosis were significantly less than that in patients with nonsignificant ICA stenosis. Mean arterial pressure (MAP) was significantly correlated with activated voxels of Brodmann area 4 (P < 0·01) and total activated voxels (P = 0·007), whereas hemoglobin and HbA1c showed no significant correlation with activated voxels of Brodmann area 4 or total activated voxels (P > 0·05).Conclusion:It is suggested that both ICA stenosis and arterial BP could influence BOLD signal, while HbA1c and hemoglobin level had no effect on BOLD signal.

Examination of contraction-induced muscle pain as a behavioral correlate of physical activity in women with and without fibromyalgia

Purpose: This study aimed to compare muscle pain intensity during a sustained isometric contraction in women with and without fibromyalgia (FM), and examine the association between muscle pain and self-reported levels of physical activity. Methods: Fourteen women with FM and 14 healthy women completed the study, where muscle pain ratings (MPRs) were obtained every 30 s during a 3 min isometric handgrip task at 25% maximal strength, and self-reported physical activity was quantified using the Baecke Physical Activity Questionnaire. Results: Women with FM were less physically active than healthy controls. During the isometric contraction, MPR progressively increased in both groups at a comparable rate, but women with FM generally reported a greater intensity of muscle pain than healthy controls. Among all women, average MPR scores were inversely associated with self-reported physical activity levels. Conclusions: Women with FM exhibit augmented muscle pain during isometric contractions and reduced physical activity than healthy controls. Furthermore, contraction-induced muscle pain is inversely associated with physical activity levels. These observations suggest that augmented muscle pain may serve as a behavioral correlate of reduced physical activity in women with FM.Implications for RehabilitationWomen with fibromyalgia experience a greater intensity of localized muscle pain in a contracting muscle compared to healthy women.The intensity of pain during muscle contraction is inversely associated with the amount of physical activity in women with and without fibromyalgia.Future studies should determine whether exercise adherence can be improved by considering the relationship between contraction-induced muscle pain and participation in routine physical activity.

Hand grips strength effect on motor function in human brain using fMRI: a pilot study

Several methods of motor tasks for fMRI scanning have been evolving from simple to more complex tasks. Motor tasks on upper extremity were applied in order to excite the increscent of motor activation on contralesional and ipsilateral hemispheres in brain. The main objective of this study is to study the different conditions for motor tasks on upper extremity that affected the brain activation. Ten healthy right handed with normal vision (3 male and 7 female, age range=20-30 years, mean=24.6 years, SD=2.21) participated in this study. Prior to the scanning, participants were trained on hand grip tasks using rubber ball and pressure gauge tool outside the scanner. During fMRI session, a block design with 30-s task blocks and alternating 30-s rest periods was employed while participants viewed a computer screen via a back projection-mirror system and instructed to follow the instruction by gripping their hand with normal and strong grips using a rubber ball. Statistical Parametric mapping (SPM8) software was used to determine the brain activation. Both tasks activated the primary motor (M1), supplementary motor area (SMA), dorsal and ventral of premotor cortex area (PMA) in left hemisphere while in right hemisphere the area of primary motor (M1) somatosensory was activated. However, the comparison between both tasks revealed that the strong hand grip showed the higher activation at M1, PMA and SMA on left hemisphere and also the area of SMA on right hemisphere. Both conditions of motor tasks could provide insights the functional organization on human brain.

Force time-history affects fatigue accumulation during repetitive handgrip tasks

Muscle fatigue is associated with a higher risk of workplace injury, in particular during repetitive tasks. This study aimed to identify the effect of a complex force–time history (a task with multiple different submaximal effort levels) on fatigue accumulation and recovery during a handgrip task. We measured surface electromyography of the brachioradialis (BRD) and flexor carpi ulnaris (FCU) of ten right hand dominant females with no history of upper limb injury while they performed a complex submaximal visually targeted gripping task. The task consisted of 15%, 30%, 45%, 30%, and 15% maximum voluntary contraction (MVC) plateaus. Each plateau was held for 15s, followed by a 3s MVC and 3s of rest. The “pyramid” was repeated until fatigue criteria were met. Grip force, average EMG and mean power frequency (MnPF) for first cycle and fatigued last cycle, were compared. Post-plateau peak grip force was on average 20.5% MVC lower during the last cycle (p<0.01). Post-plateau grip forces decreased on average by 5.1% MVC after the first 15% MVC plateau (from baseline), by 5.3% MVC after the 30% MVC plateau and 6.8% MVC after the 45% MVC plateau. Further accumulation of fatigue after the second 30% MVC plateau however was minimal, only decreasing by 1.6% MVC. Recovery appeared to occur during the last 15% MVC plateau with an increase in post plateau grip force of 1.6% MVC. Interestingly, MnPF parameters confirmed significant fatigue accumulation during the back end of a force pyramid. We conclude that in a pattern of contractions with ascending, then descending force intensity, voluntary force recovery was present when the preceding force was of a lower intensity. These findings indicate preceding demands play a role in fatigue accumulation during complex tasks.

Goal pursuit and energy conservation: energy investment increases with task demand but does not equal it

According to motivational intensity theory, energy investment in goal pursuit is determined by the motivation to avoid wasting energy. Two experiments tested this hypothesis by manipulating the difficulty of an isometric hand grip task across four levels in a between-persons (Study 1) and a within-persons (Study 2) design. Supporting motivational intensity theory’s prediction, the results showed that invested energy—indicated by exerted grip force—was a function of task difficulty: The higher the difficulty, the higher the energy investment. However, the data also indicated that participants invested considerably more energy than required, questioning the primacy of energy conservation.