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Simultaneous processing of information on multiple errors in visuomotor learning.

Kasuga S, Hirashima M, Nozaki D - PLoS ONE (2013)

Bottom Line: The proper association between planned and executed movements is crucial for motor learning because the discrepancies between them drive such learning.Our study explored how this association was determined when a single action caused the movements of multiple visual objects.These results indicated that the motor learning system utilized multiple sources of visual error information simultaneously to correct subsequent movement and that a certain averaging mechanism might be at work in the utilization process.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Science and Technology, Keio University, Yokohama, Japan.

ABSTRACT
The proper association between planned and executed movements is crucial for motor learning because the discrepancies between them drive such learning. Our study explored how this association was determined when a single action caused the movements of multiple visual objects. Participants reached toward a target by moving a cursor, which represented the right hand's position. Once every five to six normal trials, we interleaved either of two kinds of visual perturbation trials: rotation of the cursor by a certain amount (±15°, ±30°, and ±45°) around the starting position (single-cursor condition) or rotation of two cursors by different angles (+15° and -45°, 0° and 30°, etc.) that were presented simultaneously (double-cursor condition). We evaluated the aftereffects of each condition in the subsequent trial. The error sensitivity (ratio of the aftereffect to the imposed visual rotation) in the single-cursor trials decayed with the amount of rotation, indicating that the motor learning system relied to a greater extent on smaller errors. In the double-cursor trials, we obtained a coefficient that represented the degree to which each of the visual rotations contributed to the aftereffects based on the assumption that the observed aftereffects were a result of the weighted summation of the influences of the imposed visual rotations. The decaying pattern according to the amount of rotation was maintained in the coefficient of each imposed visual rotation in the double-cursor trials, but the value was reduced to approximately 40% of the corresponding error sensitivity in the single-cursor trials. We also found a further reduction of the coefficients when three distinct cursors were presented (e.g., -15°, 15°, and 30°). These results indicated that the motor learning system utilized multiple sources of visual error information simultaneously to correct subsequent movement and that a certain averaging mechanism might be at work in the utilization process.

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The results of experiments 1 and 2 are indicated in the same panel.A: The relationship between the aftereffects that were predicted by the linear integration model (eqs. 2 and 3) and the actual aftereffects. B: Comparisons between the error sensitivity (Ks) of the single-cursor trials and the estimated weighting parameter (Kd) of the double-cursor trials for each imposed visual rotation. The filled diamonds indicate Ks, and the open diamonds indicate Kd. Both Ks and Kd decayed as the magnitude of rotation increased, and Kd was about 40% of the corresponding Ks. The lines are disconnected between 10° and 15° because the data originated from different experiments. The error bars indicate ±1 SE. C: Linear regression between Kd and the corresponding Ks. The red plots indicate the parameters of experiment 1, and the blue plots indicate the parameters of experiment 2. The coefficients of regression and the confidence intervals (CI) are also shown. D: The relationship between the aftereffects that were predicted with the parameters that were estimated by leaving 1 cursor combination out at a time and the actual aftereffects.
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pone-0072741-g004: The results of experiments 1 and 2 are indicated in the same panel.A: The relationship between the aftereffects that were predicted by the linear integration model (eqs. 2 and 3) and the actual aftereffects. B: Comparisons between the error sensitivity (Ks) of the single-cursor trials and the estimated weighting parameter (Kd) of the double-cursor trials for each imposed visual rotation. The filled diamonds indicate Ks, and the open diamonds indicate Kd. Both Ks and Kd decayed as the magnitude of rotation increased, and Kd was about 40% of the corresponding Ks. The lines are disconnected between 10° and 15° because the data originated from different experiments. The error bars indicate ±1 SE. C: Linear regression between Kd and the corresponding Ks. The red plots indicate the parameters of experiment 1, and the blue plots indicate the parameters of experiment 2. The coefficients of regression and the confidence intervals (CI) are also shown. D: The relationship between the aftereffects that were predicted with the parameters that were estimated by leaving 1 cursor combination out at a time and the actual aftereffects.

Mentions: In order to investigate how the information from the cursors was used to modify the movement direction in the subsequent trial, we estimated a weighting parameter (Kd, eq. 2) for each imposed visual rotation. The linear integration model fit the actual data well (experiment 1, r2 = 0.88; experiment 2, r2 = 0.88; Fig. 4A). Two-way repeated-measures ANOVA (weighting parameter × rotation angle) showed that Kd decreased with the increasing magnitude of rotation, as in the case of Ks in the single-cursor trials (experiment 1, F5, 204 = 4.38, P<0.01; experiment 2, F3, 96 = 2.94, P<0.05; Fig. 4B). However, the main effect of the weighting parameter showed that the value of Kd for each rotated cursor was significantly smaller (experiment 1, F1, 204 = 3.89, P<0.01; experiment 2, F1, 96 = 21.4, P<0.01) than the corresponding Ks. The slopes of the linear regression between Kd and Ks were 0.40 (CI = 0.31 to 0.49) for experiment 1 and 0.36 (CI = 0.23 to 0.50) for experiment 2 (Fig. 4C).


Simultaneous processing of information on multiple errors in visuomotor learning.

Kasuga S, Hirashima M, Nozaki D - PLoS ONE (2013)

The results of experiments 1 and 2 are indicated in the same panel.A: The relationship between the aftereffects that were predicted by the linear integration model (eqs. 2 and 3) and the actual aftereffects. B: Comparisons between the error sensitivity (Ks) of the single-cursor trials and the estimated weighting parameter (Kd) of the double-cursor trials for each imposed visual rotation. The filled diamonds indicate Ks, and the open diamonds indicate Kd. Both Ks and Kd decayed as the magnitude of rotation increased, and Kd was about 40% of the corresponding Ks. The lines are disconnected between 10° and 15° because the data originated from different experiments. The error bars indicate ±1 SE. C: Linear regression between Kd and the corresponding Ks. The red plots indicate the parameters of experiment 1, and the blue plots indicate the parameters of experiment 2. The coefficients of regression and the confidence intervals (CI) are also shown. D: The relationship between the aftereffects that were predicted with the parameters that were estimated by leaving 1 cursor combination out at a time and the actual aftereffects.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3756985&req=5

pone-0072741-g004: The results of experiments 1 and 2 are indicated in the same panel.A: The relationship between the aftereffects that were predicted by the linear integration model (eqs. 2 and 3) and the actual aftereffects. B: Comparisons between the error sensitivity (Ks) of the single-cursor trials and the estimated weighting parameter (Kd) of the double-cursor trials for each imposed visual rotation. The filled diamonds indicate Ks, and the open diamonds indicate Kd. Both Ks and Kd decayed as the magnitude of rotation increased, and Kd was about 40% of the corresponding Ks. The lines are disconnected between 10° and 15° because the data originated from different experiments. The error bars indicate ±1 SE. C: Linear regression between Kd and the corresponding Ks. The red plots indicate the parameters of experiment 1, and the blue plots indicate the parameters of experiment 2. The coefficients of regression and the confidence intervals (CI) are also shown. D: The relationship between the aftereffects that were predicted with the parameters that were estimated by leaving 1 cursor combination out at a time and the actual aftereffects.
Mentions: In order to investigate how the information from the cursors was used to modify the movement direction in the subsequent trial, we estimated a weighting parameter (Kd, eq. 2) for each imposed visual rotation. The linear integration model fit the actual data well (experiment 1, r2 = 0.88; experiment 2, r2 = 0.88; Fig. 4A). Two-way repeated-measures ANOVA (weighting parameter × rotation angle) showed that Kd decreased with the increasing magnitude of rotation, as in the case of Ks in the single-cursor trials (experiment 1, F5, 204 = 4.38, P<0.01; experiment 2, F3, 96 = 2.94, P<0.05; Fig. 4B). However, the main effect of the weighting parameter showed that the value of Kd for each rotated cursor was significantly smaller (experiment 1, F1, 204 = 3.89, P<0.01; experiment 2, F1, 96 = 21.4, P<0.01) than the corresponding Ks. The slopes of the linear regression between Kd and Ks were 0.40 (CI = 0.31 to 0.49) for experiment 1 and 0.36 (CI = 0.23 to 0.50) for experiment 2 (Fig. 4C).

Bottom Line: The proper association between planned and executed movements is crucial for motor learning because the discrepancies between them drive such learning.Our study explored how this association was determined when a single action caused the movements of multiple visual objects.These results indicated that the motor learning system utilized multiple sources of visual error information simultaneously to correct subsequent movement and that a certain averaging mechanism might be at work in the utilization process.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Science and Technology, Keio University, Yokohama, Japan.

ABSTRACT
The proper association between planned and executed movements is crucial for motor learning because the discrepancies between them drive such learning. Our study explored how this association was determined when a single action caused the movements of multiple visual objects. Participants reached toward a target by moving a cursor, which represented the right hand's position. Once every five to six normal trials, we interleaved either of two kinds of visual perturbation trials: rotation of the cursor by a certain amount (±15°, ±30°, and ±45°) around the starting position (single-cursor condition) or rotation of two cursors by different angles (+15° and -45°, 0° and 30°, etc.) that were presented simultaneously (double-cursor condition). We evaluated the aftereffects of each condition in the subsequent trial. The error sensitivity (ratio of the aftereffect to the imposed visual rotation) in the single-cursor trials decayed with the amount of rotation, indicating that the motor learning system relied to a greater extent on smaller errors. In the double-cursor trials, we obtained a coefficient that represented the degree to which each of the visual rotations contributed to the aftereffects based on the assumption that the observed aftereffects were a result of the weighted summation of the influences of the imposed visual rotations. The decaying pattern according to the amount of rotation was maintained in the coefficient of each imposed visual rotation in the double-cursor trials, but the value was reduced to approximately 40% of the corresponding error sensitivity in the single-cursor trials. We also found a further reduction of the coefficients when three distinct cursors were presented (e.g., -15°, 15°, and 30°). These results indicated that the motor learning system utilized multiple sources of visual error information simultaneously to correct subsequent movement and that a certain averaging mechanism might be at work in the utilization process.

Show MeSH
Related in: MedlinePlus