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Grasping preparation enhances orientation change detection.

Gutteling TP, Kenemans JL, Neggers SF - PLoS ONE (2011)

Bottom Line: By analyzing discrimination response probabilities, we found increased perceptual sensitivity to orientation changes when subjects were instructed to grasp the bar, rather than point to it.Here, no differences in visual sensitivity between grasping and pointing were found.The present results constitute first direct evidence for increased perceptual sensitivity to a visual feature that is relevant for a certain skeletomotor act during the movement preparation phase.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands. T.Gutteling@umcutrecht.nl

ABSTRACT
Preparing a goal directed movement often requires detailed analysis of our environment. When picking up an object, its orientation, size and relative distance are relevant parameters when preparing a successful grasp. It would therefore be beneficial if the motor system is able to influence early perception such that information processing needs for action control are met at the earliest possible stage. However, only a few studies reported (indirect) evidence for action-induced visual perception improvements. We therefore aimed to provide direct evidence for a feature-specific perceptual modulation during the planning phase of a grasping action. Human subjects were instructed to either grasp or point to a bar while simultaneously performing an orientation discrimination task. The bar could slightly change its orientation during grasping preparation. By analyzing discrimination response probabilities, we found increased perceptual sensitivity to orientation changes when subjects were instructed to grasp the bar, rather than point to it. As a control experiment, the same experiment was repeated using bar luminance changes, a feature that is not relevant for either grasping or pointing. Here, no differences in visual sensitivity between grasping and pointing were found. The present results constitute first direct evidence for increased perceptual sensitivity to a visual feature that is relevant for a certain skeletomotor act during the movement preparation phase. We speculate that such action-induced perception improvements are controlled by neuronal feedback mechanisms from cortical motor planning areas to early visual cortex, similar to what was recently established for spatial perception improvements shortly before eye movements.

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Grasping angle preshaping.Mean orientation of the thumb-index vector, as a function of target bar orientation (45 or −45 deg) and experiment (orientation/luminance) in the grasping condition. The horizontal axis represents the percent movement completed (0–100%), where 0% is movement onset and 100% is the point where the bar on screen is grasped. Error bars represent the standard error (SE).
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pone-0017675-g006: Grasping angle preshaping.Mean orientation of the thumb-index vector, as a function of target bar orientation (45 or −45 deg) and experiment (orientation/luminance) in the grasping condition. The horizontal axis represents the percent movement completed (0–100%), where 0% is movement onset and 100% is the point where the bar on screen is grasped. Error bars represent the standard error (SE).

Mentions: To test for proper angle pre-shaping of the hand during grasping (that is, the alignment of the orientation of the hand with respect to the target in-flight), angle timeseries were separated for target angles of 45 and −45 degrees. These timeseries were divided in 25 time windows (where time windows 1 is movement onset and time window 25 is movement offset) and tested for significant deviation. This yields the time point in which the angle of the target bar influences the grasping action. The preshaping timecourse was averaged over all bar positions. For the orientation experiment, the difference between target angles reached significance from time window 7 (of 25) onwards (t = 4.97, p<0.001). This means pre-shaping of the hand was differentiated to target orientation from 28–32% of the grasping movement duration and onwards, which corresponds to 171–196 ms after movement onset, as the mean movement duration is 610 ms. In the luminance experiment it was slightly earlier, in time window 5 (t(15) = 3.92, p = 0.001; 20–24% of the grasping duration, 566 ms, or 113–136 ms after movement onset). See also Figure 6 for the time course of grasping preshaping to both bar orientations.


Grasping preparation enhances orientation change detection.

Gutteling TP, Kenemans JL, Neggers SF - PLoS ONE (2011)

Grasping angle preshaping.Mean orientation of the thumb-index vector, as a function of target bar orientation (45 or −45 deg) and experiment (orientation/luminance) in the grasping condition. The horizontal axis represents the percent movement completed (0–100%), where 0% is movement onset and 100% is the point where the bar on screen is grasped. Error bars represent the standard error (SE).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3050920&req=5

pone-0017675-g006: Grasping angle preshaping.Mean orientation of the thumb-index vector, as a function of target bar orientation (45 or −45 deg) and experiment (orientation/luminance) in the grasping condition. The horizontal axis represents the percent movement completed (0–100%), where 0% is movement onset and 100% is the point where the bar on screen is grasped. Error bars represent the standard error (SE).
Mentions: To test for proper angle pre-shaping of the hand during grasping (that is, the alignment of the orientation of the hand with respect to the target in-flight), angle timeseries were separated for target angles of 45 and −45 degrees. These timeseries were divided in 25 time windows (where time windows 1 is movement onset and time window 25 is movement offset) and tested for significant deviation. This yields the time point in which the angle of the target bar influences the grasping action. The preshaping timecourse was averaged over all bar positions. For the orientation experiment, the difference between target angles reached significance from time window 7 (of 25) onwards (t = 4.97, p<0.001). This means pre-shaping of the hand was differentiated to target orientation from 28–32% of the grasping movement duration and onwards, which corresponds to 171–196 ms after movement onset, as the mean movement duration is 610 ms. In the luminance experiment it was slightly earlier, in time window 5 (t(15) = 3.92, p = 0.001; 20–24% of the grasping duration, 566 ms, or 113–136 ms after movement onset). See also Figure 6 for the time course of grasping preshaping to both bar orientations.

Bottom Line: By analyzing discrimination response probabilities, we found increased perceptual sensitivity to orientation changes when subjects were instructed to grasp the bar, rather than point to it.Here, no differences in visual sensitivity between grasping and pointing were found.The present results constitute first direct evidence for increased perceptual sensitivity to a visual feature that is relevant for a certain skeletomotor act during the movement preparation phase.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands. T.Gutteling@umcutrecht.nl

ABSTRACT
Preparing a goal directed movement often requires detailed analysis of our environment. When picking up an object, its orientation, size and relative distance are relevant parameters when preparing a successful grasp. It would therefore be beneficial if the motor system is able to influence early perception such that information processing needs for action control are met at the earliest possible stage. However, only a few studies reported (indirect) evidence for action-induced visual perception improvements. We therefore aimed to provide direct evidence for a feature-specific perceptual modulation during the planning phase of a grasping action. Human subjects were instructed to either grasp or point to a bar while simultaneously performing an orientation discrimination task. The bar could slightly change its orientation during grasping preparation. By analyzing discrimination response probabilities, we found increased perceptual sensitivity to orientation changes when subjects were instructed to grasp the bar, rather than point to it. As a control experiment, the same experiment was repeated using bar luminance changes, a feature that is not relevant for either grasping or pointing. Here, no differences in visual sensitivity between grasping and pointing were found. The present results constitute first direct evidence for increased perceptual sensitivity to a visual feature that is relevant for a certain skeletomotor act during the movement preparation phase. We speculate that such action-induced perception improvements are controlled by neuronal feedback mechanisms from cortical motor planning areas to early visual cortex, similar to what was recently established for spatial perception improvements shortly before eye movements.

Show MeSH