From action goals to movement: How do we decide which hand to use when reaching for an object?

Abstract

Event Abstract Back to Event From action goals to movement: How do we decide which hand to use when reaching for an object? Richard Ivry1*, Flavio Oliveira1, Tim Verstynen1 and Joern Diedrichsen1 1 University of California, Department of Psychology, United States Deciding which hand to use for an action is one of the most frequent decisions people make in their everyday behavior. Consider the relatively simple decision of which hand to use to press an elevator button. While this decision does not require much conscious thought, it is influenced by a host of factors such as past experience, the current context and the spatial location of the button with respect to the hands. We examine this decision process in a speeded reaching task in which a target appeared at one of 10 locations along a semi-circle. Right-handed participants completed two conditions: In the Fixed condition, they were required to use one hand, either left or right in separate blocks. In the Choice condition, they were free to use either hand.Psychometric choice functions show a bias to use the dominant hand with the point of indifference shifted to the left of the midline. The reaction time data in the Choice condition were indicative of a competitive process that involves the parallel activation of action plans for each hand: RTs were slower for targets near the point of indifference compared to more eccentric targets. In contrast, the pattern was reversed (although not reliably so) in Fixed condition, presumably reflecting a bias to attend to the middle of the display. In a second experiment, we sought to perturb the competitive process with transcranial magnetic stimulation (TMS). A single pulse was applied to either left or right hemisphere posterior parietal cortex just after the onset of the target. When the TMS was applied over the left PPC, there was an increase in ipsilateral, left hand reaches. No change in performance was observed following stimulation over right PPC. These results provide further evidence of the role of PPC in the representation of response-specific decision variables. Whereas previous studies have focused on spatial decisions related to the selection of a target, the current study indicates that PPC, at least for the left hemisphere, is also involved in decisions related to the selection of an effector, even when the stimulus itself does not directly specify that information. Conference: Computations, Decisions and Movement, Giessen, Germany, 19 May - 22 May, 2010. Presentation Type: Poster Presentation Topic: Posters Citation: Ivry R, Oliveira F, Verstynen T and Diedrichsen J (2010). From action goals to movement: How do we decide which hand to use when reaching for an object?. Front. Comput. Neurosci. Conference Abstract: Computations, Decisions and Movement. doi: 10.3389/conf.fnins.2010.01.00007 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 01 Feb 2010; Published Online: 01 Feb 2010. * Correspondence: Richard Ivry, University of California, Department of Psychology, Berkeley, United States, ivry@berkeley.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Richard Ivry Flavio Oliveira Tim Verstynen Joern Diedrichsen Google Richard Ivry Flavio Oliveira Tim Verstynen Joern Diedrichsen Google Scholar Richard Ivry Flavio Oliveira Tim Verstynen Joern Diedrichsen PubMed Richard Ivry Flavio Oliveira Tim Verstynen Joern Diedrichsen Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.