title: A Rapid Tactile-Motor Reflex Automatically Guides Reaching toward Handheld Objects.
abstract: The ability to respond quickly and effectively when objects in the world suddenly change position is essential for skilled action, and previous work has documented how unexpected changes in the location of a visually presented target during reaching can elicit rapid reflexive (i.e., automatic) corrections of the hand's trajectory [1-12]. In object manipulation and tool use, the sense of touch can also provide information about changes in the location of reach targets. Consider the many tasks where we reach with one hand to part of an object grasped by the other hand: reaching to a berry while holding a branch, reaching for a cap while grasping a bottle, and reaching toward a dog's collar while holding the dog's leash. In such cases, changes in the position of the reach target, due to wind, slip, or an active agent, can be detected, in principle, through touch. Here, we show that when people reach with their right hand to a target attached to the far end of a rod contacted, at the near end, by their left hand, an unexpected change in target location caused by rod rotation rapidly evokes an effective reach correction. That is, spatial information about a change in target location provided by tactile inputs to one hand elicits a rapid correction of the other hand's trajectory. In addition to uncovering a tactile-motor reflex that can support manipulatory actions, our results demonstrate that automatic reach corrections to moving targets are not unique to visually registered changes in target location.
authors.affiliation: Department of Physiology and Pharmacology, Department of Psychology, Robarts Research Institute, Brain and Mind Institute, Western University, London, ON N6A 5B7, Canada; Department of Integrative Medical Biology, Umea University, 901 87 Umeå, Sweden. Electronic address: andrew.pruszynski@uwo.ca.
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Pruszynski
authors.affiliation: Department of Integrative Medical Biology, Umea University, 901 87 Umeå, Sweden.
authors.forename: Roland S
authors.initials: RS
authors.lastname: Johansson
authors.affiliation: Centre for Neuroscience Studies and Department of Psychology, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: J Randall
authors.initials: JR
authors.lastname: Flanagan
mesh_terms: D000328:Adult; D004576:Electromyography / Q000379:methods; D004867:Equipment Design; D006225:Hand / Q000502:physiology*; D006801:Humans; D033281:Nontherapeutic Human Experimentation; D010369:Pectoralis Muscles / Q000502:physiology; D011597:Psychomotor Performance; D012018:Reflex / Q000502:physiology*; D012399:Rotation; D014110:Touch