Effect of visuomotor-map uncertainty on visuomotor adaptation

2012 ◽  
Vol 107 (6) ◽  
pp. 1576-1585 ◽  
Author(s):  
Naoki Saijo ◽  
Hiroaki Gomi
Keyword(s):  
Feedback Control ◽  
Probe Trial ◽  
Visual Target ◽  
Hand Movement ◽  
Visuomotor Adaptation ◽  
Proprioceptive Feedback ◽  
Visuomotor Rotation ◽  
Feedback Controls ◽  
Reaching Movement ◽  
End Point

Vision and proprioception contribute to generating hand movement. If a conflict between the visual and proprioceptive feedback of hand position is given, reaching movement is disturbed initially but recovers after training. Although previous studies have predominantly investigated the adaptive change in the motor output, it is unclear whether the contributions of visual and proprioceptive feedback controls to the reaching movement are modified by visuomotor adaptation. To investigate this, we focused on the change in proprioceptive feedback control associated with visuomotor adaptation. After the adaptation to gradually introduce visuomotor rotation, the hand reached the shifted position of the visual target to move the cursor to the visual target correctly. When the cursor feedback was occasionally eliminated (probe trial), the end point of the hand movement was biased in the visual-target direction, while the movement was initiated in the adapted direction, suggesting the incomplete adaptation of proprioceptive feedback control. Moreover, after the learning of uncertain visuomotor rotation, in which the rotation angle was randomly fluctuated on a trial-by-trial basis, the end-point bias in the probe trial increased, but the initial movement direction was not affected, suggesting a reduction in the adaptation level of proprioceptive feedback control. These results suggest that the change in the relative contribution of visual and proprioceptive feedback controls to the reaching movement in response to the visuomotor-map uncertainty is involved in visuomotor adaptation, whereas feedforward control might adapt in a manner different from that of the feedback control.

The Synergistic Organization of Muscle Recruitment Constrains Visuomotor Adaptation

2009 ◽  
Vol 101 (5) ◽  
pp. 2263-2269 ◽  
Author(s):  
Aymar de Rugy ◽  
Mark R. Hinder ◽  
Daniel G. Woolley ◽  
Richard G. Carson
Keyword(s):  
Time Course ◽  
Neural Circuits ◽  
Visual Target ◽  
Sensory Information ◽  
Visuomotor Adaptation ◽  
Visuomotor Rotation ◽  
Joint Torques ◽  
Flexion Extension ◽  
Isometric Torque ◽  
The Individual

Reaching to visual targets engages the nervous system in a series of transformations between sensory information and motor commands. That which remains to be determined is the extent to which the processes that mediate sensorimotor adaptation to novel environments engage neural circuits that represent the required movement in joint-based or muscle-based coordinate systems. We sought to establish the contribution of these alternative representations to the process of visuomotor adaptation. To do so we applied a visuomotor rotation during a center-out isometric torque production task that involved flexion/extension and supination/pronation at the elbow-joint complex. In separate sessions, distinct half-quadrant rotations (i.e., 45°) were applied such that adaptation could be achieved either by only rescaling the individual joint torques (i.e., the visual target and torque target remained in the same quadrant) or by additionally requiring torque reversal at a contributing joint (i.e., the visual target and torque target were in different quadrants). Analysis of the time course of directional errors revealed that the degree of adaptation was lower (by ∼20%) when reversals in the direction of joint torques were required. It has been established previously that in this task space, a transition between supination and pronation requires the engagement of a different set of muscle synergists, whereas in a transition between flexion and extension no such change is required. The additional observation that the initial level of adaptation was lower and the subsequent aftereffects were smaller, for trials that involved a pronation–supination transition than for those that involved a flexion–extension transition, supports the conclusion that the process of adaptation engaged, at least in part, neural circuits that represent the required motor output in a muscle-based coordinate system.

scholarly journals The extent of interlimb transfer following adaptation to a novel visuomotor condition does not depend on awareness of the condition

2011 ◽  
Vol 106 (1) ◽  
pp. 259-264 ◽  
Author(s):  
Jinsung Wang ◽  
Mukta Joshi ◽  
Yuming Lei
Keyword(s):  
Visuomotor Adaptation ◽  
Visuomotor Transformation ◽  
Visuomotor Rotation ◽  
Experimental Conditions ◽  
Reaching Movement ◽  
Rotation Condition ◽  
Cognitive Awareness ◽  
Adaptation Session ◽  
Rate Of Learning ◽  
The Right

There is a controversy in the literature as to whether transfer of motor learning across the arms occurs because of an individual's cognitive awareness of the learned condition. The purpose of this study was to test whether the extent of interlimb transfer following adaptation to a novel visuomotor rotation with one arm, as well as the rate of learning acquired by the other arm, would vary depending on the subjects' awareness of the rotation condition. Awareness of the condition was varied by employing three experimental conditions. In one condition, visual rotation of the display up to 32° was gradually introduced to minimize the subjects' awareness of the rotation during targeted reaching movement. In another condition, the 32° rotation was abruptly introduced from the beginning of the adaptation session. Finally, the subjects were informed regarding the rotation prior to the adaptation session. After adaptation with the left arm under the three conditions, subjects performed reaching movement with the right arm under the same 32° rotation condition. Our results showed that the amount of initial transfer, and also the changes in performance with the right arm, did not vary significantly across the three conditions. This finding suggests that interlimb transfer of visuomotor adaptation does not occur based on an individual's awareness of the manipulation, but rather as a result of implicit generalization of the obtained visuomotor transformation across the arms.

scholarly journals Prolonged thrombocytosis in mice after 5-fluorouracil results from failure to down-regulate megakaryocyte concentration. An experimental model that dissociates regulation of megakaryocyte size and DNA content from megakaryocyte concentration

Blood ◽  
1990 ◽  
Vol 76 (3) ◽  
pp. 508-515 ◽  
Author(s):  
PJ Chenaille ◽  
SA Steward ◽  
RA Ashmun ◽  
CW Jackson
Keyword(s):  
Feedback Control ◽  
Dna Content ◽  
Inverse Relationship ◽  
Feedback Regulation ◽  
Model System ◽  
Feedback Controls ◽  
Platelet Recovery ◽  
Normal Platelet ◽  
Platelet Number ◽  
C3h Mice

Abstract Rodents treated with 150 mg/kg of 5-fluorouracil (5-FU) exhibit a marked and prolonged rebound thrombocytosis, suggesting that feedback control of one or more megakaryocyte characteristics (size, polyploidy, or concentration) is altered. To determine the changes in megakaryocytes that lead to such a profound thrombocytosis, C3H mice were injected with 150 mg/kg 5-FU, and platelet and megakaryocyte responses were examined at frequent intervals from days 1 through 25. After 5-FU injection, all megakaryocyte indices decreased, as did platelet number. However, the decrease in platelets to one third of control was greater than the decreases in megakaryocyte indices, suggesting that thrombocytopoiesis was ineffective from days 3 through 7 post 5-FU. Megakaryocyte size began to recover on day 4, followed by polyploid DNA content on day 5, and megakaryocyte concentration and platelets at 7.5 days. Megakaryocyte size peaked on days 6 through 8 (1.25 x normal), followed by megakaryocyte polyploid DNA content on day 8, megakaryocyte concentration on days 9 through 12 (2 1/2 to 3x normal), and platelets on days 12 through 15 (2x normal). Platelet levels are thought to be important in the feedback regulation of megakaryocytes; however, only polyploid DNA content distributions showed a close inverse relationship to platelet counts during both the recovery and rebound thrombocytosis phases after 5-FU. In contrast, megakaryocyte size peaked before platelet recovery commenced, while megakaryocyte concentration increased in parallel with platelets from 7.5 to 10 days post 5-FU and continued to be maintained at 2 to 3 times normal through day 13, despite platelet levels that were more than twice normal. Both megakaryocyte size and polyploid DNA content distributions shifted toward lower values in response to the rebound thrombocytosis (DNA content on day 10 and size on days 12 and 13). Splenectomy did not substantially alter the pattern of post 5-FU rebound thrombocytosis or megakaryocyte response from that seen in intact mice, indicating that splenic megakaryocytes are not responsible for the prolonged thrombocytosis seen after this drug. In summary, the prolonged thrombocytosis after 5-FU administration results from failure to down-regulate the number of precursors entering the differentiating megakaryocyte compartment. These data indicate that megakaryocyte size and DNA content are responsive to different feedback controls than megakaryocyte concentration in this model system.

scholarly journals Eye movements do not play an important role in the adaptation of hand tracking to a visuomotor rotation

2019 ◽  
Vol 121 (5) ◽  
pp. 1967-1976 ◽  
Author(s):  
Niels Gouirand ◽  
James Mathew ◽  
Eli Brenner ◽  
Frederic R. Danion
Keyword(s):  
Eye Movements ◽  
Time Course ◽  
Motor Behavior ◽  
Hand Movement ◽  
Visuomotor Adaptation ◽  
Online Control ◽  
Hand Movements ◽  
Hand Tracking ◽  
Gaze Fixation ◽  
The Gaze

Adapting hand movements to changes in our body or the environment is essential for skilled motor behavior. Although eye movements are known to assist hand movement control, how eye movements might contribute to the adaptation of hand movements remains largely unexplored. To determine to what extent eye movements contribute to visuomotor adaptation of hand tracking, participants were asked to track a visual target that followed an unpredictable trajectory with a cursor using a joystick. During blocks of trials, participants were either allowed to look wherever they liked or required to fixate a cross at the center of the screen. Eye movements were tracked to ensure gaze fixation as well as to examine free gaze behavior. The cursor initially responded normally to the joystick, but after several trials, the direction in which it responded was rotated by 90°. Although fixating the eyes had a detrimental influence on hand tracking performance, participants exhibited a rather similar time course of adaptation to rotated visual feedback in the gaze-fixed and gaze-free conditions. More importantly, there was extensive transfer of adaptation between the gaze-fixed and gaze-free conditions. We conclude that although eye movements are relevant for the online control of hand tracking, they do not play an important role in the visuomotor adaptation of such tracking. These results suggest that participants do not adapt by changing the mapping between eye and hand movements, but rather by changing the mapping between hand movements and the cursor’s motion independently of eye movements. NEW & NOTEWORTHY Eye movements assist hand movements in everyday activities, but their contribution to visuomotor adaptation remains largely unknown. We compared adaptation of hand tracking under free gaze and fixed gaze. Although our results confirm that following the target with the eyes increases the accuracy of hand movements, they unexpectedly demonstrate that gaze fixation does not hinder adaptation. These results suggest that eye movements have distinct contributions for online control and visuomotor adaptation of hand movements.

Saccade Adaptation in Response to Altered Arm Dynamics

2003 ◽  
Vol 90 (6) ◽  
pp. 4016-4021 ◽  
Author(s):  
Thrishantha Nanayakkara ◽  
Reza Shadmehr
Keyword(s):  
Feedback Control ◽  
Real Time ◽  
Internal Model ◽  
Proprioceptive Feedback ◽  
Hand Position ◽  
Formidable Challenge ◽  
Random Direction ◽  
Intact Brain ◽  
Saccade Adaptation ◽  
The Brain

The delays in sensorimotor pathways pose a formidable challenge to the implementation of stable error feedback control, and yet the intact brain has little trouble maintaining limb stability. How is this achieved? One idea is that feedback control depends not only on delayed proprioceptive feedback but also on internal models of limb dynamics. In theory, an internal model allows the brain to predict limb position. Earlier we had found that during reaching, the brain estimates hand position in real-time in a coordinate system that can be used for generating saccades. Here we tested the idea that the estimate of hand position, as expressed through saccades, depends on an internal model that adapts to dynamics of the arm. We focused on the behavior of the eyes as perturbations were applied to the unseen hand. We found that when the hand was perturbed from stable posture with a 100-ms force pulse of random direction and magnitude, a saccade was generated on average at 182 ms postpulse onset to a position that was an unbiased estimate of real-time hand position. To test whether planning of saccades depended on an internal model of arm dynamics, arm dynamics were altered either predictably or unpredictably during the postpulse period. When arm dynamics were predictable, saccade amplitudes changed to reflect the change in the arm's behavior. We suggest that proprioceptive feedback from the arm is integrated into an adaptable internal model that computes an estimate of current hand position in eye-centered coordinates.

scholarly journals Can patients with cerebellar disease switch learning mechanisms to reduce their adaptation deficits?

Brain ◽  
2019 ◽  
Vol 142 (3) ◽  
pp. 662-673 ◽  
Author(s):  
Aaron L Wong ◽  
Cherie L Marvel ◽  
Jordan A Taylor ◽  
John W Krakauer
Keyword(s):  
Prediction Error ◽  
Poor Performance ◽  
Visuomotor Adaptation ◽  
Cerebellar Degeneration ◽  
Prediction Errors ◽  
Cerebellar Disease ◽  
Learning Mechanisms ◽  
Visuomotor Rotation ◽  
Age Related ◽  
Sensory Prediction

Abstract Systematic perturbations in motor adaptation tasks are primarily countered by learning from sensory-prediction errors, with secondary contributions from other learning processes. Despite the availability of these additional processes, particularly the use of explicit re-aiming to counteract observed target errors, patients with cerebellar degeneration are surprisingly unable to compensate for their sensory-prediction error deficits by spontaneously switching to another learning mechanism. We hypothesized that if the nature of the task was changed—by allowing vision of the hand, which eliminates sensory-prediction errors—patients could be induced to preferentially adopt aiming strategies to solve visuomotor rotations. To test this, we first developed a novel visuomotor rotation paradigm that provides participants with vision of their hand in addition to the cursor, effectively setting the sensory-prediction error signal to zero. We demonstrated in younger healthy control subjects that this promotes a switch to strategic re-aiming based on target errors. We then showed that with vision of the hand, patients with cerebellar degeneration could also switch to an aiming strategy in response to visuomotor rotations, performing similarly to age-matched participants (older controls). Moreover, patients could retrieve their learned aiming solution after vision of the hand was removed (although they could not improve beyond what they retrieved), and retain it for at least 1 year. Both patients and older controls, however, exhibited impaired overall adaptation performance compared to younger healthy controls (age 18–33 years), likely due to age-related reductions in spatial and working memory. Patients also failed to generalize, i.e. they were unable to adopt analogous aiming strategies in response to novel rotations. Hence, there appears to be an inescapable obligatory dependence on sensory-prediction error-based learning—even when this system is impaired in patients with cerebellar disease. The persistence of sensory-prediction error-based learning effectively suppresses a switch to target error-based learning, which perhaps explains the unexpectedly poor performance by patients with cerebellar degeneration in visuomotor adaptation tasks.

scholarly journals Trial-by-trial analysis of intermanual transfer during visuomotor adaptation

2011 ◽  
Vol 106 (6) ◽  
pp. 3157-3172 ◽  
Author(s):  
Jordan A. Taylor ◽  
Greg J. Wojaczynski ◽  
Richard B. Ivry
Keyword(s):  
Skill Acquisition ◽  
Training Transfer ◽  
Visuomotor Adaptation ◽  
Single Step ◽  
Hand Movements ◽  
Intermanual Transfer ◽  
Visuomotor Rotation ◽  
Left Hand ◽  
Right Hand ◽  
The Right

Studies of intermanual transfer have been used to probe representations formed during skill acquisition. We employ a new method that provides a continuous assay of intermanual transfer, intermixing right- and left-hand trials while limiting visual feedback to right-hand movements. We manipulated the degree of awareness of the visuomotor rotation, introducing a 22.5° perturbation in either an abrupt single step or gradually in ∼1° increments every 10 trials. Intermanual transfer was observed with the direction of left-hand movements shifting in the opposite direction of the rotation over the course of training. The transfer on left-hand trials was less than that observed in the right hand. Moreover, the magnitude of transfer was larger in our mixed-limb design compared with the standard blocked design in which transfer is only probed at the end of training. Transfer was similar in the abrupt and gradual groups, suggesting that awareness of the perturbation has little effect on intermanual transfer. In a final experiment, participants were provided with a strategy to offset an abrupt rotation, a method that has been shown to increase error over the course of training due to the operation of sensorimotor adaptation. This deterioration was also observed on left-hand probe trials, providing further support that awareness has little effect on intermanual transfer. These results indicate that intermanual transfer is not dependent on the implementation of cognitively assisted strategies that participants might adopt when they become aware that the visuomotor mapping has been perturbed. Rather, the results indicate that the information available to processes involved in adaptation entails some degree of effector independence.

scholarly journals Permanence of a Single Species System with Distributed Time Delay and Feedback Control

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Yali Shen ◽  
Fengqin Zhang ◽  
Kai Wang
Keyword(s):  
Time Delay ◽  
Feedback Control ◽  
Single Species ◽  
Feedback Controls ◽  
Distributed Time Delay

We study the permanence of a classofsingle species system with distributed time delay and feedback controls. General criteria on permanence are established in this paper. A very important fact is found in our results; that is, the feedback control is harmless to the permanence of species.

Hand-held tools with complex kinematics are efficiently incorporated into movement planning and online control

2012 ◽  
Vol 108 (7) ◽  
pp. 1954-1964 ◽  
Author(s):  
Lee A. Baugh ◽  
Erica Hoe ◽  
J. Randall Flanagan
Keyword(s):  
Online Control ◽  
Movement Planning ◽  
Control Mechanisms ◽  
Movement Initiation ◽  
Reaching Movement ◽  
Hand Motion ◽  
Reversal Condition ◽  
End Point ◽  
Point Motion ◽  
Time Required

Certain hand-held tools alter the mapping between hand motion and motion of the tool end point that must be controlled in order to perform a task. For example, when using a pool cue, the motion of the cue tip is reversed relative to the hand. Previous studies have shown that the time required to initiate a reaching movement (Fernandez-Ruiz J, Wong W, Armstrong IT, Flanagan JR. Behav Brain Res 219: 8–14, 2011), or correct an ongoing reaching movement (Gritsenko V, Kalaska JF. J Neurophysiol 104: 3084–3104, 2010), is prolonged when the mapping between hand motion and motion of a cursor controlled by the hand is reversed. Here we show that these time costs can be significantly reduced when the reversal is instantiated by a virtual hand-held tool. Participants grasped the near end of a virtual tool, consisting of a rod connecting two circles, and moved the end point to displayed targets. In the reversal condition, the rod translated through, and rotated about, a pivot point such that there was a left-right reversal between hand and end point motion. In the nonreversal control, the tool translated with the hand. As expected, when only the two circles were presented, movement initiation and correction times were much longer in the reversal condition. However, when full vision of the tool was provided, the reaction time cost was almost eliminated. These results indicate that tools with complex kinematics can be efficiently incorporated into sensorimotor control mechanisms used in movement planning and online control.

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