Perceived effort affects choice of limb and reaction time of movements.

MedStar author(s):
Citation: Journal of Neurophysiology. 125(1):63-73, 2021 01 01.PMID: 33146065Institution: MedStar National Rehabilitation NetworkForm of publication: Journal ArticleMedline article type(s): Journal ArticleSubject headings: *Arm/ph [Physiology] | *Choice Behavior | *Movement | Adult | Female | Functional Laterality | Humans | Male | Reaction Time | Visual PerceptionYear: 2021Local holdings: Available online from MWHC library: 1997 - present (after 1 year)ISSN:
  • 0022-3077
Name of journal: Journal of neurophysiologyAbstract: The decision regarding which arm to use to perform a task reflects a complex process that can be influenced by many factors, including effort requirements of acquiring the goal. In this study, we considered a virtual reality environment in which people reached to a visual target in three-dimensional space. To vary the cost of reaching, we altered the visual feedback associated with motion of one arm but not the other. This altered the extent of motion that was required to reach, thus changing the effort required to acquire the goal. We then measured how that change in effort affected the decision regarding which arm to use, as well as the preparation time for the movement that ensued. As expected, with increased visual amplification of one arm (reduced effort to reach the goal), subjects increased the probability of choosing that arm. Surprisingly, however, the reaction times to start these movements were also reduced: despite constancy of the visual representation of the target, reaction times were shorter for movements with less effort. Thus, as the perceived effort associated with accomplishing a goal was reduced for a given limb, the decision-making process was biased toward use of that limb. Furthermore, movements that were perceived to be less effortful were performed with shorter reaction times. These results suggest that visual amplification can alter the perceived effort associated with using a limb, thus increasing frequency of use. This may provide a useful method to increase use of a limb during rehabilitation. NEW & NOTEWORTHY We report that visual amplification may serve as an effective means to alter the perceived effort associated with use of a limb. This method may provide an effective tool with which use of the affected limb can be encouraged noninvasively after neurological injury.All authors: Lee SW, Lum PS, Shadmehr R, Wang JOriginally published: Journal of Neurophysiology. 125(1):63-73, 2021 Jan 01.Fiscal year: FY2021Fiscal year of original publication: FY2021Digital Object Identifier: ORCID: Date added to catalog: 2021-02-17
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Item type Current library Collection Call number Status Date due Barcode
Journal Article MedStar Authors Catalog Article 33146065 Available 33146065

Available online from MWHC library: 1997 - present (after 1 year)

The decision regarding which arm to use to perform a task reflects a complex process that can be influenced by many factors, including effort requirements of acquiring the goal. In this study, we considered a virtual reality environment in which people reached to a visual target in three-dimensional space. To vary the cost of reaching, we altered the visual feedback associated with motion of one arm but not the other. This altered the extent of motion that was required to reach, thus changing the effort required to acquire the goal. We then measured how that change in effort affected the decision regarding which arm to use, as well as the preparation time for the movement that ensued. As expected, with increased visual amplification of one arm (reduced effort to reach the goal), subjects increased the probability of choosing that arm. Surprisingly, however, the reaction times to start these movements were also reduced: despite constancy of the visual representation of the target, reaction times were shorter for movements with less effort. Thus, as the perceived effort associated with accomplishing a goal was reduced for a given limb, the decision-making process was biased toward use of that limb. Furthermore, movements that were perceived to be less effortful were performed with shorter reaction times. These results suggest that visual amplification can alter the perceived effort associated with using a limb, thus increasing frequency of use. This may provide a useful method to increase use of a limb during rehabilitation. NEW & NOTEWORTHY We report that visual amplification may serve as an effective means to alter the perceived effort associated with use of a limb. This method may provide an effective tool with which use of the affected limb can be encouraged noninvasively after neurological injury.

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