scholarly journals Neurophysiological changes in the visuomotor network after practicing a motor task

2018 ◽  
Vol 120 (1) ◽  
pp. 239-249 ◽  
Author(s):  
James E. Gehringer ◽  
David J. Arpin ◽  
Elizabeth Heinrichs-Graham ◽  
Tony W. Wilson ◽  
Max J. Kurz
Keyword(s):  
Motor Learning ◽  
Motor Planning ◽  
Motor Task ◽  
Force Production ◽  
Oscillatory Activity ◽  
Matching Task ◽  
Force Output ◽  
Motor Action ◽  
Visuomotor Transformations ◽  
Target Matching

Although it is well appreciated that practicing a motor task updates the associated internal model, it is still unknown how the cortical oscillations linked with the motor action change with practice. The present study investigates the short-term changes (e.g., fast motor learning) in the α- and β-event-related desynchronizations (ERD) associated with the production of a motor action. To this end, we used magnetoencephalography to identify changes in the α- and β-ERD in healthy adults after participants practiced a novel isometric ankle plantarflexion target-matching task. After practicing, the participants matched the targets faster and had improved accuracy, faster force production, and a reduced amount of variability in the force output when trying to match the target. Parallel with the behavioral results, the strength of the β-ERD across the motor-planning and execution stages was reduced after practice in the sensorimotor and occipital cortexes. No pre/postpractice changes were found in the α-ERD during motor planning or execution. Together, these outcomes suggest that fast motor learning is associated with a decrease in β-ERD power. The decreased strength likely reflects a more refined motor plan, a reduction in neural resources needed to perform the task, and/or an enhancement of the processes that are involved in the visuomotor transformations that occur before the onset of the motor action. These results may augment the development of neurologically based practice strategies and/or lead to new practice strategies that increase motor learning. NEW & NOTEWORTHY We aimed to determine the effects of practice on the movement-related cortical oscillatory activity. Following practice, we found that the performance of the ankle plantarflexion target-matching task improved and the power of the β-oscillations decreased in the sensorimotor and occipital cortexes. These novel findings capture the β-oscillatory activity changes in the sensorimotor and occipital cortexes that are coupled with behavioral changes to demonstrate the effects of motor learning.

scholarly journals Age-related differences in the motor planning of a lower leg target matching task

2015 ◽  
Vol 44 ◽  
pp. 299-306 ◽  
Author(s):  
Brenda L. Davies ◽  
James E. Gehringer ◽  
Max J. Kurz
Keyword(s):  
Motor Planning ◽  
Lower Leg ◽  
Matching Task ◽  
Age Related ◽  
Target Matching

Intermittency in the Control of Continuous Force Production

2000 ◽  
Vol 84 (4) ◽  
pp. 1708-1718 ◽  
Author(s):  
Andrew B. Slifkin ◽  
David E. Vaillancourt ◽  
Karl M. Newell
Keyword(s):  
Visual Feedback ◽  
Visual Information ◽  
Spectral Power ◽  
Force Production ◽  
Motor Output ◽  
Force Variability ◽  
Force Output ◽  
Feedback Information ◽  
Information Processes ◽  
Feedback Frequency

The purpose of the current investigation was to examine the influence of intermittency in visual information processes on intermittency in the control continuous force production. Adult human participants were required to maintain force at, and minimize variability around, a force target over an extended duration (15 s), while the intermittency of on-line visual feedback presentation was varied across conditions. This was accomplished by varying the frequency of successive force-feedback deliveries presented on a video display. As a function of a 128-fold increase in feedback frequency (0.2 to 25.6 Hz), performance quality improved according to hyperbolic functions (e.g., force variability decayed), reaching asymptotic values near the 6.4-Hz feedback frequency level. Thus, the briefest interval over which visual information could be integrated and used to correct errors in motor output was approximately 150 ms. The observed reductions in force variability were correlated with parallel declines in spectral power at about 1 Hz in the frequency profile of force output. In contrast, power at higher frequencies in the force output spectrum were uncorrelated with increases in feedback frequency. Thus, there was a considerable lag between the generation of motor output corrections (1 Hz) and the processing of visual feedback information (6.4 Hz). To reconcile these differences in visual and motor processing times, we proposed a model where error information is accumulated by visual information processes at a maximum frequency of 6.4 per second, and the motor system generates a correction on the basis of the accumulated information at the end of each 1-s interval.

Effects of hypoxia and hypercapnia on geniohyoid contractility and endurance

1991 ◽  
Vol 71 (2) ◽  
pp. 709-715 ◽  
Author(s):  
R. J. Salmone ◽  
E. Van Lunteren
Keyword(s):  
Force Production ◽  
Upper Airway ◽  
Muscle Performance ◽  
Severe Hypoxia ◽  
Force Frequency ◽  
Force Output ◽  
Frequency Curve ◽  
Dilator Muscle ◽  
Index Ratio ◽  
Mild Hypoxia

Sleep apnea and other respiratory diseases produce hypoxemia and hypercapnia, factors that adversely affect skeletal muscle performance. To examine the effects of these chemical alterations on force production by an upper airway dilator muscle, the contractile and endurance characteristics of the geniohyoid muscle were examined in situ during severe hypoxia (arterial PO2 less than 40 Torr), mild hypoxia (PO2 45–65 Torr), and hypercapnia (PCO2 55–80 Torr) and compared with hyperoxic-normocapnic conditions in anesthetized cats. Muscles were studied at optimal length, and contractile force was assessed in response to supramaximal electrical stimulation of the hypoglossal nerve (n = 7 cats) or geniohyoid muscle (n = 2 cats). There were no significant changes in the twitch kinetics or force-frequency curve of the geniohyoid muscle during hypoxia or hypercapnia. However, the endurance of the geniohyoid, as reflected in the fatigue index (ratio of force at 2 min to initial force in response to 40-Hz stimulation at a duty cycle 0.33), was significantly reduced by severe hypoxia but not by hypercapnia or mild hypoxia. In addition, the downward shift in the force-frequency curve after the repetitive stimulation protocol was greater during hypoxia than hyperoxia, especially at higher frequencies. In conclusion, the ability of the geniohyoid muscle to maintain force output during high levels of activation is adversely affected by severe hypoxia but not mild hypoxia or hypercapnia. However, none of these chemical perturbations affected muscle contractility acutely.

scholarly journals Dual contributions of cerebellar-thalamic networks to learning and offline consolidation of a complex motor task

2020 ◽  
Author(s):  
Andres P Varani ◽  
Romain W Sala ◽  
Caroline Mailhes-Hamon ◽  
Jimena L Frontera ◽  
Clément Léna ◽  
...  
Keyword(s):  
Motor Learning ◽  
Motor Task ◽  
Cerebellar Nuclei ◽  
Specific Inhibition ◽  
Thalamic Nuclei ◽  
Related Information ◽  
Midline Thalamus ◽  
Ventral Thalamus ◽  
Complex Motor ◽  
Offline Processing

SUMMARYThe contribution of cerebellum to motor learning is often considered to be limited to adaptation, a short-timescale tuning of reflexes and previous learned skills. Yet, the cerebellum is reciprocally connected to two main players of motor learning, the motor cortex and the basal ganglia, via the ventral and midline thalamus respectively. Here, we evaluated the contribution of cerebellar neurons projecting to these thalamic nuclei in a skilled locomotion task in mice. In the cerebellar nuclei, we found task-specific neuronal activities during the task, and lasting changes after the task suggesting an offline processing of task-related information. Using pathway-specific inhibition, we found that dentate neurons projecting to the midline thalamus contribute to learning and retrieval, while interposed neurons projecting to the ventral thalamus contribute to the offline consolidation of savings. Our results thus show that two parallel cerebello-thalamic pathways perform distinct computations operating on distinct timescales in motor learning.

scholarly journals Motor learning and transfer: from feedback to feedforward control

2019 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Motor Learning ◽  
Muscle Activity ◽  
Shoulder Joint ◽  
Stretch Reflex ◽  
Feedforward Control ◽  
Motor Task ◽  
Joint Torques ◽  
Motor Commands ◽  
Shoulder Muscle ◽  
Long Latency

AbstractPrevious work has demonstrated that when learning a new motor task, the nervous system modifies feedforward (ie. voluntary) motor commands and that such learning transfers to fast feedback (ie. reflex) responses evoked by mechanical perturbations. Here we show the inverse, that learning new feedback responses transfers to feedforward motor commands. Sixty human participants (34 females) used a robotic exoskeleton and either 1) received short duration mechanical perturbations (20 ms) that created pure elbow rotation or 2) generated self-initiated pure elbow rotations. They did so with the shoulder joint free to rotate (normal arm dynamics) or locked (altered arm dynamics) by the robotic manipulandum. With the shoulder unlocked, the perturbation evoked clear shoulder muscle activity in the long-latency stretch reflex epoch (50-100ms post-perturbation), as required for countering the imposed joint torques, but little muscle activity thereafter in the so-called voluntary response. After locking the shoulder joint, which alters the required joint torques to counter pure elbow rotation, we found a reliable reduction in the long-latency stretch reflex over many trials. This reduction transferred to feedforward control as we observed 1) a reduction in shoulder muscle activity during self-initiated pure elbow rotation trials and 2) kinematic errors (ie. aftereffects) in the direction predicted when failing to compensate for normal arm dynamics, even though participants never practiced self-initiated movements with the shoulder locked. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

scholarly journals Neck linker docking is critical for Kinesin-1 force generation in cells but at a cost to motor speed and processivity

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Breane G Budaitis ◽  
Shashank Jariwala ◽  
Dana N Reinemann ◽  
Kristin I Schimert ◽  
Guido Scarabelli ◽  
...  
Keyword(s):  
Optical Trap ◽  
Force Production ◽  
Force Generation ◽  
Motor Speed ◽  
Force Output ◽  
Mechanical Element ◽  
Membrane Bound ◽  
Dynamics Simulations ◽  
Run Lengths ◽  
In Cells

Kinesin force generation involves ATP-induced docking of the neck linker (NL) along the motor core. However, the roles of the proposed steps of NL docking, cover-neck bundle (CNB) and asparagine latch (N-latch) formation, during force generation are unclear. Furthermore, the necessity of NL docking for transport of membrane-bound cargo in cells has not been tested. We generated kinesin-1 motors impaired in CNB and/or N-latch formation based on molecular dynamics simulations. The mutant motors displayed reduced force output and inability to stall in optical trap assays but exhibited increased speeds, run lengths, and landing rates under unloaded conditions. NL docking thus enhances force production but at a cost to speed and processivity. In cells, teams of mutant motors were hindered in their ability to drive transport of Golgi elements (high-load cargo) but not peroxisomes (low-load cargo). These results demonstrate that the NL serves as a mechanical element for kinesin-1 transport under physiological conditions.

scholarly journals Learning the same motor task twice impairs its retention in a time- and dose-dependent manner

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202556
Author(s):  
R. Hamel ◽  
L. Dallaire-Jean ◽  
É. De La Fontaine ◽  
J. F. Lepage ◽  
P. M. Bernier
Keyword(s):  
Motor Learning ◽  
Refractory Period ◽  
Motor Task ◽  
Dependent Manner ◽  
Learning Session ◽  
Concurrent Learning ◽  
Performance Improvements ◽  
Dependent Process ◽  
Initial Learning ◽  
Dose Dependent

Anterograde interference emerges when two differing tasks are learned in close temporal proximity, an effect repeatedly attributed to a competition between differing task memories. However, recent development alternatively suggests that initial learning may trigger a refractory period that occludes neuroplasticity and impairs subsequent learning, consequently mediating interference independently of memory competition. Accordingly, this study tested the hypothesis that interference can emerge when the same motor task is being learned twice, that is when competition between memories is prevented. In a first experiment, the inter-session interval (ISI) between two identical motor learning sessions was manipulated to be 2 min, 1 h or 24 h. Results revealed that retention of the second session was impaired as compared to the first one when the ISI was 2 min but not when it was 1 h or 24 h, indicating a time-dependent process. Results from a second experiment replicated those of the first one and revealed that adding a third motor learning session with a 2 min ISI further impaired retention, indicating a dose-dependent process. Results from a third experiment revealed that the retention impairments did not take place when a learning session was preceded by simple rehearsal of the motor task without concurrent learning, thus ruling out fatigue and confirming that retention is impaired specifically when preceded by a learning session. Altogether, the present results suggest that competing memories is not the sole mechanism mediating anterograde interference and introduce the possibility that a time- and dose-dependent refractory period—independent of fatigue—also contributes to its emergence. One possibility is that learning transiently perturbs the homeostasis of learning-related neuronal substrates. Introducing additional learning when homeostasis is still perturbed may not only impair performance improvements, but also memory formation.

scholarly journals Children with cerebral palsy have altered oscillatory activity in the motor and visual cortices during a knee motor task

2017 ◽  
Vol 15 ◽  
pp. 298-305 ◽  
Author(s):  
Max J. Kurz ◽  
Amy L. Proskovec ◽  
James E. Gehringer ◽  
Elizabeth Heinrichs-Graham ◽  
Tony W. Wilson
Keyword(s):  
Cerebral Palsy ◽  
Motor Task ◽  
Oscillatory Activity ◽  
Children With Cerebral Palsy ◽  
Visual Cortices

Inter-Personal Motor Synergy: Co-working Strategy Depends on Task Constraints

2021 ◽  
Author(s):  
Sara Honarvar ◽  
Mia Caminita ◽  
Hossein Ehsani ◽  
Hyun Joon Kwon ◽  
Yancy Diaz-Mercado ◽  
...  
Keyword(s):  
Force Production ◽  
Matching Task ◽  
Task Constraint ◽  
Experimental Conditions ◽  
Task Constraints ◽  
Force Matching ◽  
Additional Task ◽  
Central Nervous Systems ◽  
Fixed Condition ◽  
Motor Synergy

We investigated the role of task constraints on inter-personal interactions. Twenty-one pairs of co-workers performed a finger force production task on force sensors placed at two ends of a seesaw-like apparatus and matched a combined target force of 20N for 23 seconds over ten trials. There were two experimental conditions: 1) FIXED: the seesaw apparatus was mechanically held in place so that the only task constraint was to match the 20N resultant force, and 2) MOVING: the lever in the apparatus was allowed to rotate freely around its fulcrum, acting like a seesaw, so an additional task constraint to (implicitly) balance the resultant moment was added. We hypothesized that the additional task constraint of moment stabilization imposed on the MOVING condition would deteriorate task performance compared to the FIXED condition; however, this was rejected as the performance of the force matching task was similar between two conditions. We also hypothesized that the central nervous systems (CNSs) would employ distinct co-working strategies or inter-personal motor synergy (IPMS) between conditions to satisfy different task constraints, which was supported by our results. Negative covariance between co-worker's forces in the FIXED condition suggested a force stabilization strategy, while positive covariance in the MOVING condition suggested a moment stabilization strategy, implying that independent CNSs adopt distinct IPMSs depending on task constraints. We speculate that, in the absence of a central neural controller, shared visual and mechanical connections between co-workers may suffice to trigger modulations in the cerebellum of each CNS to satisfy competing task constraints.

Differences in spectral profiles between rostral and caudal premotor cortex when hand-eye actions are decoupled

2013 ◽  
Vol 110 (4) ◽  
pp. 952-963 ◽  
Author(s):  
Patricia F. Sayegh ◽  
Kara M. Hawkins ◽  
Kari L. Hoffman ◽  
Lauren E. Sergio
Keyword(s):  
Visual Stimulus ◽  
Rhesus Macaques ◽  
Premotor Cortex ◽  
Standard Condition ◽  
Motor Task ◽  
Movement Control ◽  
Oscillatory Activity ◽  
Visually Guided ◽  
Control Research ◽  
Spectral Profiles

The aim of this research was to understand how the brain controls voluntary movement when not directly interacting with the object of interest. In the present study, we examined the role of premotor cortex in this behavior. The goal of this study was to characterize the oscillatory activity within the caudal and rostral subdivisions of dorsal premotor cortex (PMdc and PMdr) with a change from the most basic reaching movement to one that involves a simple dissociation between the actions of the eyes and hand. We were specifically interested in how PMdr and PMdc respond when the eyes and hand are decoupled by moving along different spatial planes. We recorded single-unit activity and local field potentials within PMdr and PMdc from two rhesus macaques during performance of two types of visually guided reaches. During the standard condition, a visually guided reach was performed whereby the visual stimulus guiding the movement was the target of the reach itself. During the nonstandard condition, the visual stimulus provided information about the direction of the required movement but was not the target of the motor output. We observed distinct task-related and topographical differences between PMdr and PMdc. Our results support functional differences between PMdr and PMdc during visually guided reaching. PMdr activity appears more involved in integrating the rule-based aspects of a visually guided reach, whereas PMdc is more involved in the online updating of the decoupled reach. More broadly, our results highlight the necessity of accounting for the nonstandard nature of a motor task when interpreting movement control research data.

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