scholarly journals Strengthened Corticosubcortical Functional Connectivity during Muscle Fatigue

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Zhiguo Jiang ◽  
Xiao-Feng Wang ◽  
Guang H. Yue
Keyword(s):  
Motor Control ◽  
Functional Connectivity ◽  
Quantile Regression ◽  
Muscle Fatigue ◽  
Motor Performance ◽  
Primary Motor Cortex ◽  
Motor Task ◽  
Voluntary Contraction ◽  
Control Network ◽  
Subcortical Structures

The present study examined functional connectivity (FC) between functional MRI (fMRI) signals of the primary motor cortex (M1) and each of the three subcortical neural structures, cerebellum (CB), basal ganglia (BG), and thalamus (TL), during muscle fatigue using the quantile regression technique. Understanding activation relation between the subcortical structures and the M1 during prolonged motor performance should help delineate how central motor control network modulates acute perturbations at peripheral sensorimotor system such as muscle fatigue. Ten healthy subjects participated in the study and completed a 20-minute intermittent handgrip motor task at 50% of their maximal voluntary contraction (MVC) level. Quantile regression analyses were carried out to compare the FC between the contralateral (left) M1 and CB, BG, and TL in the minimal (beginning 100 s) versus significant (ending 100 s) fatigue stages. Widespread, statistically significant increases in FC were found in bilateral BG, CB, and TL with the left M1 during significant versus minimal fatigue stages. Our results imply that these subcortical nuclei are critical components in the motor control network and actively involved in modulating voluntary muscle fatigue, possibly, by working together with the M1 to strengthen the descending central command to prolong the motor performance.

scholarly journals Fatigue induces behavioural improvements in the unfatigued hand via altered functional connectivity and neurochemicals in cortical motor areas

2021 ◽  
Author(s):  
Justin W Andrushko ◽  
Jacob M Levenstein ◽  
Catharina Zich ◽  
Evan C Edmond ◽  
Jon Campbell ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Motor Performance ◽  
Primary Motor Cortex ◽  
Maximum Voluntary Contraction ◽  
Reaction Time Task ◽  
Voluntary Contraction ◽  
Sensorimotor Network ◽  
Before And After ◽  
Contralateral Hand ◽  
Fatiguing Exercise

In humans, motor learning is underpinned by changes in functional connectivity (FC) across the sensorimotor network. Unilateral exercise-induced fatigue increases FC in the ipsilateral primary motor cortex (M1) and supplementary motor area (SMA); areas involved in motor planning and execution of the contralateral hand. Unilateral fatiguing exercise is therefore a promising potential approach to augment motor performance in the non-fatigued, contralateral, hand. In a within-participant, controlled, randomized, cross-over design, 15 right-handed adults had two magnetic resonance imaging (MRI) sessions, where functional MRI and MR Spectroscopic Imaging were acquired before and after repeated right-hand contractions at either 5% or 50% maximum voluntary contraction (MVC). Before and after scanning, response times (RTs) were determined in both hands, and after scanning, participants performed a serial reaction time task (SRTT) with their left, unfatigued, hand. Nine minutes of 50% MVC contractions resulted in fatigue. This unimanual fatigue improved motor performance, as indexed by decreased RTs, in the contralateral hand. Although fatigue had no significant effects on sequence learning, fatigue led to a significant increase in the transfer of the learned skill to the untrained hand. These behavioural effects were supported by significant neural changes: an increase in SMA-SMA functional connectivity, and increased connectivity between right M1 and right Orbitofrontal Cortex. At a neurochemical level, the degree of fatigue-induced decrease in GABA in left M1, left and right SMA correlated with subsequent behavioural improvements in the left-hand. These results support unilateral fatiguing exercise as a potential therapeutic intervention in a range of neurological and orthopedic conditions.

scholarly journals Motor demand-dependent improvement in accuracy following low-frequency transcranial magnetic stimulation of left motor cortex

2011 ◽  
Vol 106 (4) ◽  
pp. 1614-1621 ◽  
Author(s):  
Cathrin M. Buetefisch ◽  
Benjamin Hines ◽  
Linda Shuster ◽  
Paola Pergami ◽  
Adam Mathes
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Motor Performance ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Motor Task ◽  
Low Frequency ◽  
Afferent Input ◽  
Low Frequency Rtms

The role of primary motor cortex (M1) in the control of voluntary movements is still unclear. In brain functional imaging studies of unilateral hand performance, bilateral M1 activation is inconsistently observed, and disruptions of M1 using repetitive transcranial magnetic stimulation (rTMS) lead to variable results in the hand motor performance. As the motor tasks differed qualitatively in these studies, it is conceivable that M1 contribution differs depending on the level of skillfulness. The objective of the present study was to determine whether M1 contribution to hand motor performance differed depending on the level of precision of the motor task. Here, we used low-frequency rTMS of left M1 to determine its effect on the performance of a pointing task that allows the parametric increase of the level of precision and thereby increase the level of required precision quantitatively. We found that low-frequency rTMS improved performance in both hands for the task with the highest demand on precision, whereas performance remained unchanged for the tasks with lower demands. These results suggest that the functional relevance of M1 activity for motor performance changes as a function of motor demand. The bilateral effect of rTMS to left M1 would also support the notion of M1 functions at a higher level in motor control by integrating afferent input from nonprimary motor areas.

scholarly journals EEG-Based Spectral Analysis Showing Brainwave Changes Related to Modulating Progressive Fatigue During a Prolonged Intermittent Motor Task

2021 ◽  
Author(s):  
Easter S. Suviseshamuthu ◽  
Vikram Shenoy Handiru ◽  
Didier Allexandre ◽  
Armand Hoxha ◽  
Soha Saleh ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Spectral Power ◽  
Maximum Voluntary Contraction ◽  
Motor Task ◽  
Voluntary Contraction ◽  
Muscle Contractions ◽  
Healthy Population ◽  
Time Frequency ◽  
Beta Power ◽  
Source Level

ABSTRACTRepeatedly performing a submaximal motor task for a prolonged period of time leads to muscle fatigue manifested by its reduced capacity to generate force or power. Fatigue resulted from voluntary muscle contractions comprises a central and peripheral component, which demands a gradually increasing effort to perform the task as time elapses. However, we still lack a complete understanding of brain contribution to the enhancement of effort to cope with progressing fatigue because of repeated submaximal muscle contractions. The knowledge of how the muscle fatigue modulates brain activities in healthy population will help rationalize why certain patients experience exacerbated fatigue while carrying out mundane tasks. The intermittent motor tasks closely resemble many activities of daily living (ADL), thus remaining physiologically relevant to study fatigue. The scope of this study is therefore to investigate the EEG-based brain activation patterns in healthy subjects performing intermittent submaximal muscle contractions until self-perceived exhaustion. Fourteen participants (median age 51.5 years; age range 26 − 72 years; 5 males) repeated elbow flexion contractions at 40% maximum voluntary contraction by following visual cues displayed on an oscilloscope screen until subjective exhaustion. Each contraction lasted ≈ 5 s with a 2-s rest between trials. The force, EEG, and surface EMG (from elbow joint muscles) data were simultaneously collected. After preprocessing, we selected a subset of trials at the beginning, middle, and end of the study session representing brain activities germane to mild, moderate, and severe fatigue conditions, respectively, to compare and contrast the changes in the EEG time-frequency (TF) characteristics across the conditions. The TF analyses were conducted both at the channel and source level. The outcome of channel- and source-level analyses reveals that the theta, alpha, and beta power spectral densities (PSDs) vary in proportion to fatigue levels in cortical motor areas. Importantly, the pairwise PSD differences between the fatigue conditions survived the statistical inferential tests with a p-value threshold of 0.05. We observed a statistically significant change in the band-specific spectral power in relation to the graded fatigue from both the steady- and post-contraction EEG data. The findings would enhance our understanding on the etiology and physiology of voluntary motor-action-related fatigue and provide pointers to counteract the perception of muscle weakness and lack of motor endurance associated with ADL. The study outcome would help evaluate how clinical conditions such as neurological disorders and cancer treatment alter neural mechanisms underlying fatigue in future studies, and develop therapeutic strategies for restoring the patients’ ability to participate in ADL by mitigating the central and muscle fatigue.

scholarly journals Somatosensory electrical stimulation improves skill acquisition, consolidation, and transfer by increasing sensorimotor activity and connectivity

2018 ◽  
Vol 120 (1) ◽  
pp. 281-290 ◽  
Author(s):  
Menno P. Veldman ◽  
Natasha M. Maurits ◽  
Inge Zijdewind ◽  
Nicola A. Maffiuletti ◽  
Stella van Middelkoop ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Skill Acquisition ◽  
Motor Performance ◽  
Sensorimotor Integration ◽  
Primary Motor Cortex ◽  
Subcortical Structures ◽  
Left Hand ◽  
Phase Slope ◽  
Neuronal Mechanisms ◽  
Multifactorial Approach

The interaction between the somatosensory and motor systems is important for normal human motor function and learning. Enhancing somatosensory input using somatosensory electrical stimulation (SES) can increase motor performance, but the neuronal mechanisms underlying these effects are largely unknown. With EEG, we examined whether skill acquisition, consolidation, and interlimb transfer after SES was related to increased activity in sensorimotor regions, as assessed by the N30 somatosensory evoked potential or rather increased connectivity between these regions, as assessed by the phase slope index (PSI). Right- and left-hand motor performance and EEG measures were taken before, immediately after, and 24 h ( day 2) after either SES ( n = 12; 5 men) or Control ( n = 12; 5 men). The results showed skill acquisition and consolidation in the stimulated right hand immediately after SES (6%) and on day 2 (9%) and interlimb transfer to the nonstimulated left hand on day 2 relative to Control (8%, all P < 0.05). Increases in N30 amplitudes correlated with skill acquisition while PSI from electrodes that represent the posterior parietal and primary somatosensory cortex to the electrode representing the primary motor cortex correlated with skill consolidation. In contrast, interlimb transfer did not correlate with the EEG-derived neurophysiological estimates obtained in the present study, which may indicate the involvement of subcortical structures in interlimb transfer after SES. In conclusion, weak peripheral somatosensory inputs in the form of SES improve skill acquisition, consolidation, and interlimb transfer that coincide with different cortical adaptations, including enhanced N30 amplitudes and PSI.NEW & NOTEWORTHY The relationship between adaptations in synaptic plasticity and motor learning following somatosensory electrical stimulation (SES) is incompletely understood. Here, we used for the first time a multifactorial approach that examined skill acquisition, consolidation, and interlimb transfer following 20 min of SES. In addition, we quantified sensorimotor integration and the magnitude and direction of connectivity with EEG. Following artificial electrical stimulation, increases in sensorimotor integration and connectivity were found to correlate with skill acquisition and consolidation, respectively.

scholarly journals Development of a trunk motor paradigm for use in neuroimaging

2020 ◽  
Vol 11 (1) ◽  
pp. 193-200
Author(s):  
Elizabeth Saunders ◽  
Brian C. Clark ◽  
Leatha A. Clark ◽  
Dustin R. Grooms
Keyword(s):  
Motor Control ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Erector Spinae ◽  
Head Motion ◽  
Low Back ◽  
Cyclic Contraction ◽  
Cyclic Contractions ◽  
Measurement Units ◽  
Healthy Participants

AbstractThe purpose of this study was to quantify head motion between isometric erector spinae (ES) contraction strategies, paradigms, and intensities in the development of a neuroimaging protocol for the study of neural activity associated with trunk motor control in individuals with low back pain. Ten healthy participants completed two contraction strategies; (1) a supine upper spine (US) press and (2) a supine lower extremity (LE) press. Each contraction strategy was performed at electromyographic (EMG) contraction intensities of 30, 40, 50, and 60% of an individually determined maximum voluntary contraction (MVC) (±10% range for each respective intensity) with real-time, EMG biofeedback. A cyclic contraction paradigm was performed at 30% of MVC with US and LE contraction strategies. Inertial measurement units (IMUs) quantified head motion to determine the viability of each paradigm for neuroimaging. US vs LE hold contractions induced no differences in head motion. Hold contractions elicited significantly less head motion relative to cyclic contractions. Contraction intensity increased head motion in a linear fashion with 30% MVC having the least head motion and 60% the highest. The LE hold contraction strategy, below 50% MVC, was found to be the most viable trunk motor control neuroimaging paradigm.

Altered Resting-State Frontoparietal Control Network in Children with Attention-Deficit/Hyperactivity Disorder

2015 ◽  
Vol 21 (4) ◽  
pp. 271-284 ◽  
Author(s):  
Hsiang-Yuan Lin ◽  
Wen-Yih Isaac Tseng ◽  
Meng-Chuan Lai ◽  
Kayako Matsuo ◽  
Susan Shur-Fen Gau
Keyword(s):  
Attention Deficit Hyperactivity Disorder ◽  
Prefrontal Cortex ◽  
Functional Connectivity ◽  
Resting State ◽  
Control Network ◽  
Children With Adhd ◽  
Hyperactivity Disorder ◽  
Anterior Prefrontal Cortex ◽  
The Right ◽  
Frontoparietal Control Network

AbstractThe frontoparietal control network, anatomically and functionally interposed between the dorsal attention network and default mode network, underpins executive control functions. Individuals with attention-deficit/hyperactivity disorder (ADHD) commonly exhibit deficits in executive functions, which are mainly mediated by the frontoparietal control network. Involvement of the frontoparietal control network based on the anterior prefrontal cortex in neurobiological mechanisms of ADHD has yet to be tested. We used resting-state functional MRI and seed-based correlation analyses to investigate functional connectivity of the frontoparietal control network in a sample of 25 children with ADHD (7–14 years; mean 9.94±1.77 years; 20 males), and 25 age-, sex-, and performance IQ-matched typically developing (TD) children. All participants had limited in-scanner head motion. Spearman’s rank correlations were used to test the associations between altered patterns of functional connectivity with clinical symptoms and executive functions, measured by the Conners’ Continuous Performance Test and Spatial Span in the Cambridge Neuropsychological Test Automated Battery. Compared with TD children, children with ADHD demonstrated weaker connectivity between the right anterior prefrontal cortex (PFC) and the right ventrolateral PFC, and between the left anterior PFC and the right inferior parietal lobule. Furthermore, this aberrant connectivity of the frontoparietal control network in ADHD was associated with symptoms of impulsivity and opposition-defiance, as well as impaired response inhibition and attentional control. The findings support potential integration of the disconnection model and the executive dysfunction model for ADHD. Atypical frontoparietal control network may play a pivotal role in the pathophysiology of ADHD. (JINS, 2015, 21, 271–284)

scholarly journals Demand on skillfulness modulates interhemispheric inhibition of motor cortices

2016 ◽  
Vol 115 (6) ◽  
pp. 2803-2813 ◽  
Author(s):  
Miles Wischnewski ◽  
Greg M. Kowalski ◽  
Farrah Rink ◽  
Samir R. Belagaje ◽  
Marc W. Haut ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Motor Task ◽  
Conditioning Stimulus ◽  
Motor Evoked Potential ◽  
Inhibitory Effect ◽  
Left Hand ◽  
The Mean ◽  
Small Targets ◽  
Healthy Participants

The role of primary motor cortex (M1) in the control of hand movements is still unclear. Functional magnetic resonance imaging (fMRI) studies of unimanual performance reported a relationship between level of precision of a motor task and additional ipsilateral M1 (iM1) activation. In the present study, we determined whether the demand on accuracy of a movement influences the magnitude of the inhibitory effect between primary motor cortices (IHI). We used transcranial magnetic stimulation (TMS) to measure active IHI (aIHI) of the iM1 on the contralateral M1 (cM1) in the premovement period of a left-hand motor task. Ten healthy participants manipulated a joystick to point to targets of two different sizes. For aIHI, the conditioning stimulus (CS) was applied to iM1, and the test stimulus (TS) to cM1, with an interstimulus interval of 10 ms. The amount of the inhibitory effect of the CS on the motor-evoked potential (MEP) of the subsequent TS was expressed as percentage of the mean MEP amplitude evoked by the single TS. Across different time points of aIHI measurements in the premovement period, there was a significant effect for target size on aIHI. Preparing to point to small targets was associated with weaker aIHI compared with pointing to large targets. The present findings suggest that, during the premovement period, aIHI from iM1 on cM1 is modulated by the demand on accuracy of the motor task. This is consistent with task fMRI findings showing bilateral M1 activation during high-precision movements but only unilateral M1 activity during low-precision movements.

Intramuscular and surface electromyogram changes during muscle fatigue

1986 ◽  
Vol 60 (4) ◽  
pp. 1179-1185 ◽  
Author(s):  
T. Moritani ◽  
M. Muro ◽  
A. Nagata
Keyword(s):  
Muscle Fatigue ◽  
Biceps Brachii ◽  
Surface Emg ◽  
Firing Frequency ◽  
Voluntary Contraction ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Surface Electromyogram ◽  
Spike Amplitude ◽  
Frequency Power

Twelve male subjects were tested to determine the effects of motor unit (MU) recruitment and firing frequency on the surface electromyogram (EMG) frequency power spectra during sustained maximal voluntary contraction (MVC) and 50% MVC of the biceps brachii muscle. Both the intramuscular MU spikes and surface EMG were recorded simultaneously and analyzed by means of a computer-aided intramuscular spike amplitude-frequency histogram and frequency power spectral analysis, respectively. Results indicated that both mean power frequency (MPF) and amplitude (rmsEMG) of the surface EMG fell significantly (P less than 0.001) together with a progressive reduction in MU spike amplitude and firing frequency during sustained MVC. During 50% MVC there was a significant decline in MPF (P less than 0.001), but this decline was accompanied by a significant increase in rmsEMG (P less than 0.001) and a progressive MU recruitment as evidenced by an increased number of MUs with relatively large spike amplitude. Our data suggest that the surface EMG amplitude could better represent the underlying MU activity during muscle fatigue and the frequency powers spectral shift may or may not reflect changes in MU recruitment and rate-coding patterns.

scholarly journals The Effects of Functionally Guided, Connectivity-Based rTMS on Amygdala Activation

2021 ◽  
Vol 11 (4) ◽  
pp. 494
Author(s):  
Lysianne Beynel ◽  
Ethan Campbell ◽  
Maria Naclerio ◽  
Jeffrey T. Galla ◽  
Angikar Ghosal ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Psychiatric Disorders ◽  
Interaction Analysis ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Preliminary Evidence ◽  
Therapeutic Effects ◽  
Subcortical Structures ◽  
Video Clips ◽  
Amygdala Activation ◽  
Psychophysiological Interaction

While repetitive transcranial magnetic stimulation (rTMS) is widely used to treat psychiatric disorders, innovations are needed to improve its efficacy. An important limitation is that while psychiatric disorders are associated with fronto-limbic dysregulation, rTMS does not have sufficient depth penetration to modulate affected subcortical structures. Recent advances in task-related functional connectivity provide a means to better link superficial and deeper cortical sources with the possibility of increasing fronto-limbic modulation to induce stronger therapeutic effects. The objective of this pilot study was to test whether task-related, connectivity-based rTMS could modulate amygdala activation through its connectivity with the medial prefrontal cortex (mPFC). fMRI was collected to identify a node in the mPFC showing the strongest connectivity with the amygdala, as defined by psychophysiological interaction analysis. To promote Hebbian-like plasticity, and potentially stronger modulation, 5 Hz rTMS was applied while participants viewed frightening video-clips that engaged the fronto-limbic network. Significant increases in both the mPFC and amygdala were found for active rTMS compared to sham, offering promising preliminary evidence that functional connectivity-based targeting may provide a useful approach to treat network dysregulation. Further research is needed to better understand connectivity influences on rTMS effects to leverage this information to improve therapeutic applications.

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