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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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Related in: MedlinePlus

Lack of significant differences in standard deviations (SD) of the aftereffects that were obtained from all participants between the single- and the double-cursor trials.A black bar indicates the averaged SD of all of the single-cursor trials. The white bars indicate the averaged SD of the double-cursor trials of the same direction (“Same direction”), without rotation (“With no rotation”), and of the opposite direction (“Opposite direction”). The error bars indicate ±1 SE.
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pone-0072741-g006: Lack of significant differences in standard deviations (SD) of the aftereffects that were obtained from all participants between the single- and the double-cursor trials.A black bar indicates the averaged SD of all of the single-cursor trials. The white bars indicate the averaged SD of the double-cursor trials of the same direction (“Same direction”), without rotation (“With no rotation”), and of the opposite direction (“Opposite direction”). The error bars indicate ±1 SE.

Mentions: The spatial averaging of targets is one strategy that can be utilized when there are multiple movement goals for reaching [14]. However, in our paradigm, the results showed that it was unlikely that our motor system utilized the averaged direction of cursors as an error. Figure 6 indicates how the aftereffects were related to the mean value of the two visual rotations: each color plot corresponds to each of the differences in the angles between the two rotations (the data for 0° indicates the data for the single-cursor trial). As the difference in the angles becomes greater, the aftereffect to the mean value of the rotations becomes smaller and the deviation from the single-cursor trial becomes greater. Therefore, the motor learning system does not simply utilize the averaged visual error information to correct the subsequent movement direction.


Simultaneous processing of information on multiple errors in visuomotor learning.

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

Lack of significant differences in standard deviations (SD) of the aftereffects that were obtained from all participants between the single- and the double-cursor trials.A black bar indicates the averaged SD of all of the single-cursor trials. The white bars indicate the averaged SD of the double-cursor trials of the same direction (“Same direction”), without rotation (“With no rotation”), and of the opposite direction (“Opposite direction”). The error bars indicate ±1 SE.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756985&req=5

pone-0072741-g006: Lack of significant differences in standard deviations (SD) of the aftereffects that were obtained from all participants between the single- and the double-cursor trials.A black bar indicates the averaged SD of all of the single-cursor trials. The white bars indicate the averaged SD of the double-cursor trials of the same direction (“Same direction”), without rotation (“With no rotation”), and of the opposite direction (“Opposite direction”). The error bars indicate ±1 SE.
Mentions: The spatial averaging of targets is one strategy that can be utilized when there are multiple movement goals for reaching [14]. However, in our paradigm, the results showed that it was unlikely that our motor system utilized the averaged direction of cursors as an error. Figure 6 indicates how the aftereffects were related to the mean value of the two visual rotations: each color plot corresponds to each of the differences in the angles between the two rotations (the data for 0° indicates the data for the single-cursor trial). As the difference in the angles becomes greater, the aftereffect to the mean value of the rotations becomes smaller and the deviation from the single-cursor trial becomes greater. Therefore, the motor learning system does not simply utilize the averaged visual error information to correct the subsequent movement direction.

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