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Visuomotor adaptation needs a validation of prediction error by feedback error.

Gaveau V, Prablanc C, Laurent D, Rossetti Y, Priot AE - Front Hum Neurosci (2014)

Bottom Line: As far as subjects remained unaware of the optical deviation and self-assigned pointing errors, prediction error alone was insufficient to induce adaptation.These results indicate a critical role of hand-to-target feedback error signals in visuomotor adaptation; consistent with recent neurophysiological findings, they suggest that a combination of feedback and prediction error signals is necessary for eliciting aftereffects.They also suggest that feedback error updates the prediction of reafferences when a visual perturbation is introduced gradually and cognitive factors are eliminated or strongly attenuated.

View Article: PubMed Central - PubMed

Affiliation: INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center Bron, France.

ABSTRACT
The processes underlying short-term plasticity induced by visuomotor adaptation to a shifted visual field are still debated. Two main sources of error can induce motor adaptation: reaching feedback errors, which correspond to visually perceived discrepancies between hand and target positions, and errors between predicted and actual visual reafferences of the moving hand. These two sources of error are closely intertwined and difficult to disentangle, as both the target and the reaching limb are simultaneously visible. Accordingly, the goal of the present study was to clarify the relative contributions of these two types of errors during a pointing task under prism-displaced vision. In "terminal feedback error" condition, viewing of their hand by subjects was allowed only at movement end, simultaneously with viewing of the target. In "movement prediction error" condition, viewing of the hand was limited to movement duration, in the absence of any visual target, and error signals arose solely from comparisons between predicted and actual reafferences of the hand. In order to prevent intentional corrections of errors, a subthreshold, progressive stepwise increase in prism deviation was used, so that subjects remained unaware of the visual deviation applied in both conditions. An adaptive aftereffect was observed in the "terminal feedback error" condition only. As far as subjects remained unaware of the optical deviation and self-assigned pointing errors, prediction error alone was insufficient to induce adaptation. These results indicate a critical role of hand-to-target feedback error signals in visuomotor adaptation; consistent with recent neurophysiological findings, they suggest that a combination of feedback and prediction error signals is necessary for eliciting aftereffects. They also suggest that feedback error updates the prediction of reafferences when a visual perturbation is introduced gradually and cognitive factors are eliminated or strongly attenuated.

No MeSH data available.


Related in: MedlinePlus

(A) Pointing aftereffects as a function of target for the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Standard errors are indicated by vertical bars. (B) Pointing aftereffects as a function of repetition number in the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Error bars show ± 1 SE of the mean across subjects for each condition. For the “terminal feedback error” condition, the best-fitting exponential-decay curve is shown.
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Figure 3: (A) Pointing aftereffects as a function of target for the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Standard errors are indicated by vertical bars. (B) Pointing aftereffects as a function of repetition number in the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Error bars show ± 1 SE of the mean across subjects for each condition. For the “terminal feedback error” condition, the best-fitting exponential-decay curve is shown.

Mentions: Repeated-measure ANOVA on the mean pointing errors showed a significant effect of session for the “terminal feedback error” condition [F(1,8) = 23.18; p < 0.005] but not for the “movement prediction error” condition [F(1,8) = 001; p = 0.98]. There was no significant interaction between the session and target factors [F(3,24) = 0.14; p = 0.93] for the “terminal feedback error” condition, consistent with homogenous transfer of adaptation to untrained target locations (see Figure 3A). T-tests showed a significant aftereffect for each target: 48 ± 8.2 mm for T1 [t(8) = 5.83, p < 0.0005]; 48.1 ± 8.7 mm for T2 [t(8) = 5.55, p < 0.0001]; 49.1 ± 10.2 mm for T3 [t(8) = 4.8, p < 0.005]; 45 ± 14.5 mm for T4 [t(8) = 3.11, p < 0.05]. The average aftereffect, 47.6 mm, represented 33.5% of the 25-diopter (142 mm) deviation. No significant aftereffects were found for any of the target positions in the “movement prediction error” condition (minimum p > 0.56).


Visuomotor adaptation needs a validation of prediction error by feedback error.

Gaveau V, Prablanc C, Laurent D, Rossetti Y, Priot AE - Front Hum Neurosci (2014)

(A) Pointing aftereffects as a function of target for the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Standard errors are indicated by vertical bars. (B) Pointing aftereffects as a function of repetition number in the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Error bars show ± 1 SE of the mean across subjects for each condition. For the “terminal feedback error” condition, the best-fitting exponential-decay curve is shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4219430&req=5

Figure 3: (A) Pointing aftereffects as a function of target for the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Standard errors are indicated by vertical bars. (B) Pointing aftereffects as a function of repetition number in the “terminal feedback error” and “movement prediction error” conditions. Each point represents the mean aftereffect across all subjects during the “terminal feedback error” condition (filled red circles) or the “movement prediction error” condition (open blue circles). Error bars show ± 1 SE of the mean across subjects for each condition. For the “terminal feedback error” condition, the best-fitting exponential-decay curve is shown.
Mentions: Repeated-measure ANOVA on the mean pointing errors showed a significant effect of session for the “terminal feedback error” condition [F(1,8) = 23.18; p < 0.005] but not for the “movement prediction error” condition [F(1,8) = 001; p = 0.98]. There was no significant interaction between the session and target factors [F(3,24) = 0.14; p = 0.93] for the “terminal feedback error” condition, consistent with homogenous transfer of adaptation to untrained target locations (see Figure 3A). T-tests showed a significant aftereffect for each target: 48 ± 8.2 mm for T1 [t(8) = 5.83, p < 0.0005]; 48.1 ± 8.7 mm for T2 [t(8) = 5.55, p < 0.0001]; 49.1 ± 10.2 mm for T3 [t(8) = 4.8, p < 0.005]; 45 ± 14.5 mm for T4 [t(8) = 3.11, p < 0.05]. The average aftereffect, 47.6 mm, represented 33.5% of the 25-diopter (142 mm) deviation. No significant aftereffects were found for any of the target positions in the “movement prediction error” condition (minimum p > 0.56).

Bottom Line: As far as subjects remained unaware of the optical deviation and self-assigned pointing errors, prediction error alone was insufficient to induce adaptation.These results indicate a critical role of hand-to-target feedback error signals in visuomotor adaptation; consistent with recent neurophysiological findings, they suggest that a combination of feedback and prediction error signals is necessary for eliciting aftereffects.They also suggest that feedback error updates the prediction of reafferences when a visual perturbation is introduced gradually and cognitive factors are eliminated or strongly attenuated.

View Article: PubMed Central - PubMed

Affiliation: INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center Bron, France.

ABSTRACT
The processes underlying short-term plasticity induced by visuomotor adaptation to a shifted visual field are still debated. Two main sources of error can induce motor adaptation: reaching feedback errors, which correspond to visually perceived discrepancies between hand and target positions, and errors between predicted and actual visual reafferences of the moving hand. These two sources of error are closely intertwined and difficult to disentangle, as both the target and the reaching limb are simultaneously visible. Accordingly, the goal of the present study was to clarify the relative contributions of these two types of errors during a pointing task under prism-displaced vision. In "terminal feedback error" condition, viewing of their hand by subjects was allowed only at movement end, simultaneously with viewing of the target. In "movement prediction error" condition, viewing of the hand was limited to movement duration, in the absence of any visual target, and error signals arose solely from comparisons between predicted and actual reafferences of the hand. In order to prevent intentional corrections of errors, a subthreshold, progressive stepwise increase in prism deviation was used, so that subjects remained unaware of the visual deviation applied in both conditions. An adaptive aftereffect was observed in the "terminal feedback error" condition only. As far as subjects remained unaware of the optical deviation and self-assigned pointing errors, prediction error alone was insufficient to induce adaptation. These results indicate a critical role of hand-to-target feedback error signals in visuomotor adaptation; consistent with recent neurophysiological findings, they suggest that a combination of feedback and prediction error signals is necessary for eliciting aftereffects. They also suggest that feedback error updates the prediction of reafferences when a visual perturbation is introduced gradually and cognitive factors are eliminated or strongly attenuated.

No MeSH data available.


Related in: MedlinePlus