Modelling Skill Acquiring Process using Electomyogram Analysis : A case study of arm reaching task

2003 ◽  
Vol 2003 (0) ◽  
pp. 135
Author(s):  
K. Kita ◽  
W. Yu ◽  
R. Katoh ◽  
H. Yokoi ◽  
Y. Kakazu
Keyword(s):  
Reaching Task ◽  
Arm Reaching

Analysis of skill acquisition process: A case study of arm reaching task

2009 ◽  
Vol 57 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Kahori Kita ◽  
Ryu Kato ◽  
Hiroshi Yokoi ◽  
Tamio Arai
Keyword(s):  
Skill Acquisition ◽  
Acquisition Process ◽  
Reaching Task ◽  
Arm Reaching

Modest Gaze-Related Discharge Modulation in Monkey Dorsal Premotor Cortex During a Reaching Task Performed With Free Fixation

2002 ◽  
Vol 88 (2) ◽  
pp. 1064-1072 ◽  
Author(s):  
Paul Cisek ◽  
John F. Kalaska
Keyword(s):  
Premotor Cortex ◽  
Cell Activity ◽  
Delay Period ◽  
Gaze Direction ◽  
Dorsal Premotor Cortex ◽  
Experimental Conditions ◽  
Reaching Task ◽  
Oculomotor Behavior ◽  
Arm Reaching ◽  
Gaze Angle

Recent studies have shown that gaze angle modulates reach-related neural activity in many cortical areas, including the dorsal premotor cortex (PMd), when gaze direction is experimentally controlled by lengthy periods of imposed fixation. We looked for gaze-related modulation in PMd during the brief fixations that occur when a monkey is allowed to look around freely without experimentally imposed gaze control while performing a center-out delayed arm-reaching task. During the course of the instructed-delay period, we found significant effects of gaze angle in 27–51% of PMd cells. However, for 90–95% of cells, these effects accounted for <20% of the observed discharge variance. The effect of gaze was significantly weaker than the effect of reach-related variables. In particular, cell activity during the delay period was more strongly related to the intended movement expressed in arm-related coordinates than in gaze-related coordinates. Under the same experimental conditions, many cells in medial parietal cortex exhibited much stronger gaze-related modulation and expressed intended movement in gaze-related coordinates. In summary, gaze direction-related modulation of cell activity is indeed expressed in PMd during the brief fixations that occur in natural oculomotor behavior, but its overall effect on cell activity is modest.

scholarly journals Chronic Stroke Survivors Improve Reaching Accuracy by Reducing Movement Variability at the Trained Movement Speed

2017 ◽  
Vol 31 (6) ◽  
pp. 499-508 ◽  
Author(s):  
Ulrike Hammerbeck ◽  
Nada Yousif ◽  
Damon Hoad ◽  
Richard Greenwood ◽  
Jörn Diedrichsen ◽  
...  
Keyword(s):  
Chronic Phase ◽  
Training Group ◽  
Chronic Stroke ◽  
Movement Speed ◽  
Stroke Survivors ◽  
Movement Variability ◽  
Reaching Task ◽  
Arm Reaching ◽  
Fast Training ◽  
Elbow Movement

Background. Recovery from stroke is often said to have “plateaued” after 6 to 12 months. Yet training can still improve performance even in the chronic phase. Here we investigate the biomechanics of accuracy improvements during a reaching task and test whether they are affected by the speed at which movements are practiced. Method. We trained 36 chronic stroke survivors (57.5 years, SD ± 11.5; 10 females) over 4 consecutive days to improve endpoint accuracy in an arm-reaching task (420 repetitions/day). Half of the group trained using fast movements and the other half slow movements. The trunk was constrained allowing only shoulder and elbow movement for task performance. Results. Before training, movements were variable, tended to undershoot the target, and terminated in contralateral workspace (flexion bias). Both groups improved movement accuracy by reducing trial-to-trial variability; however, change in endpoint bias (systematic error) was not significant. Improvements were greatest at the trained movement speed and generalized to other speeds in the fast training group. Small but significant improvements were observed in clinical measures in the fast training group. Conclusions. The reduction in trial-to-trial variability without an alteration to endpoint bias suggests that improvements are achieved by better control over motor commands within the existing repertoire. Thus, 4 days’ training allows stroke survivors to improve movements that they can already make. Whether new movement patterns can be acquired in the chronic phase will need to be tested in longer term studies. We recommend that training needs to be performed at slow and fast movement speeds to enhance generalization.

Experimental Observations on the Central Nervous System’s Governing Strategies on the Arm Reaching With Reduced Mobility

2012 ◽  
Author(s):  
Hyosang Moon ◽  
Nina P. Robson ◽  
Reza Langari ◽  
John J. Buchanan
Keyword(s):  
Motion Planning ◽  
Reaching Task ◽  
Dynamic Constraints ◽  
Hand Path ◽  
Minimum Jerk ◽  
Arm Reaching ◽  
Inverse Kinematics Problem ◽  
Planning Strategies ◽  
Point To Point ◽  
Reduced Mobility

For the motion planning of a point–to–point reaching task with a healthy arm, the CNS tends to plan the shortest hand path between two task points with a bell–shaped velocity profile. If any kinematic or dynamic constraints are imposed on the arm, the CNS adapts to the changes by incorporating learning mechanism into the motion planning. This paper seeks to identify the modified motion planning strategies of the CNS when the elbow joint is constrained to move. We present an experimental protocol, where subjects perform point–to–point reaching tasks with a lightweight elbow brace to restrict the joint kinematics with a minimal effect on the arm dynamics. From the experimental observations, the human strategies on each aspect of motion planning (i.e. hand path geometry, speed of the motion, and the arm posture selection) are hypothesized. The hypothesized strategies are developed as models and compared with the experimental data. As a result, we found that the hand path follows the rhumb line on the constraint workspace while the speed profile preserves a bell–shape, which can be roughly approximated by the minimum jerk model. In addition, by comparing the joint contributions data with and without the elbow constraint, it is hypothesized that the CNS resolves the redundancy of the inverse kinematics problem by reducing the kinetic energy of the limbs.

scholarly journals A Multiscale, Systems-level, Neuropharmacological Model of Cortico-Basal Ganglia System for Arm Reaching under Normal, Parkinsonian and Levodopa Medication Conditions

2021 ◽  
Author(s):  
Sandeep Sathyanandan Nair ◽  
Vignayanandam Ravindernath Muddapu ◽  
V. Srinivasa Chakravarthy
Keyword(s):  
Basal Ganglia ◽  
Success Rate ◽  
Cell Loss ◽  
Drug Dosage ◽  
Biophysical Model ◽  
Substantia Nigra Pars Compacta ◽  
Reaching Task ◽  
Arm Reaching ◽  
Proposed Model ◽  
Cardinal Symptoms

ABSTRACTThe root cause of Parkinson’s disease (PD) is the death of dopaminergic neurons in Substantia Nigra pars compacta (SNc). The exact cause of this cell death is still not known. Loss of SNc cells manifest as the cardinal symptoms of PD, including tremor, rigidity, bradykinesia, and postural imbalance. To investigate the PD condition in detail and understand the link between loss of cells in SNc and PD symptoms, it is important to have an integrated multiscale computational model that can replicate the symptoms at the behavioural level by evoking the key cellular and molecular underlying mechanisms that contribute to the pathology. In line with this objective, we present a multiscale integrated model of cortico-basal ganglia motor circuitry for arm reaching task, incorporating a detailed biophysical model of SNc dopaminergic neuron. Earlier researchers have shown that fluctuations in dopamine (DA) signals are analogous to reward/punishment signals, thereby prompting application of concepts from reinforcement learning (RL) to modelling the basal ganglia system. In our model, we replace the abstract representations of reward with the realistic variable of extracellular DA released by a network of SNc cells and incorporate it with the RL-based behavioural model, which simulates the arm reaching task. Our results showed that as SNc cell loss increases, the percentage success rate to reach the target decreases, and average time to reach the target increases. With levodopa (L-DOPA) medication, both the success rate and the average time to reach the target improved significantly. The proposed model also exhibits how differential dopaminergic axonal degeneration in basal ganglia results in various cardinal symptoms of PD as manifest in reaching movements. From the model results, we were able to show the side effects of L-DOPA mediation, such as wearing off and peak dosage dyskinesias. Moreover, from the results, we were able to predict the optimum dosage for varying degrees of cell loss and L-DOPA medication. The proposed model has a potential clinical application where drug dosage can be optimized as per patient characteristics. We conclude that our model presents a realistic and efficient way of simulating the PD pathology conditions and the effect of levodopa medication, thereby giving a reliable indicator towards the optimization of the drug dosage.

scholarly journals The serial reaction time task revisited: a study on motor sequence learning with an arm-reaching task

2008 ◽  
Vol 194 (1) ◽  
pp. 143-155 ◽  
Author(s):  
Clara Moisello ◽  
Domenica Crupi ◽  
Eugene Tunik ◽  
Angelo Quartarone ◽  
Marco Bove ◽  
...  
Keyword(s):  
Reaction Time ◽  
Sequence Learning ◽  
Reaction Time Task ◽  
Serial Reaction Time Task ◽  
Serial Reaction Time ◽  
Motor Sequence Learning ◽  
Motor Sequence ◽  
Reaching Task ◽  
Arm Reaching ◽  
Serial Reaction

Roles of the medial frontal cortices in the selection, storage and retrieval of response tactics in a voluntary arm-reaching task

2011 ◽  
Vol 71 ◽  
pp. e380
Author(s):  
Yoshiya Matsuzaka ◽  
Yuutaro Saito ◽  
Jun Tanji ◽  
Hajime Mushiake
Keyword(s):  
Reaching Task ◽  
Storage And Retrieval ◽  
Arm Reaching

scholarly journals Dopamine neurons encode errors in predicting movement trigger occurrence

2015 ◽  
Vol 113 (4) ◽  
pp. 1110-1123 ◽  
Author(s):  
Benjamin Pasquereau ◽  
Robert S. Turner
Keyword(s):  
Hazard Rate ◽  
Dynamic Environment ◽  
Reaction Times ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Prediction Errors ◽  
Reaching Task ◽  
Foreperiod Duration ◽  
Arm Reaching ◽  
Other Information

The capacity to anticipate the timing of events in a dynamic environment allows us to optimize the processes necessary for perceiving, attending to, and responding to them. Such anticipation requires neuronal mechanisms that track the passage of time and use this representation, combined with prior experience, to estimate the likelihood that an event will occur (i.e., the event's “hazard rate”). Although hazard-like ramps in activity have been observed in several cortical areas in preparation for movement, it remains unclear how such time-dependent probabilities are estimated to optimize response performance. We studied the spiking activity of dopamine neurons in the substantia nigra pars compacta of monkeys during an arm-reaching task for which the foreperiod preceding the “go” signal varied randomly along a uniform distribution. After extended training, the monkeys' reaction times correlated inversely with foreperiod duration, reflecting a progressive anticipation of the go signal according to its hazard rate. Many dopamine neurons modulated their firing rates as predicted by a succession of hazard-related prediction errors. First, as time passed during the foreperiod, slowly decreasing anticipatory activity tracked the elapsed time as if encoding negative prediction errors. Then, when the go signal appeared, a phasic response encoded the temporal unpredictability of the event, consistent with a positive prediction error. Neither the anticipatory nor the phasic signals were affected by the anticipated magnitudes of future reward or effort, or by parameters of the subsequent movement. These results are consistent with the notion that dopamine neurons encode hazard-related prediction errors independently of other information.

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