Pointing to a visual target that disappears prior to movement requires the maintenance of a memory representation about the location of the target. It has been shown that a target can be stored egocentrically, allocentrically, or in both frames of reference simultaneously. The main goal of the present study was to compare the accuracy and kinematics of a pointing movement to a remembered target when egocentric, allocentric, or combined egocentric and allocentric coding was possible. The task was to localize, memorize, and reach to a remembered target. Condition 1 was the “no-context” condition and involved presenting the target in a completely dark environment (egocentric condition). For 2 other conditions, the target was presented within a visual context provided by an illuminated square. Condition 2 was the “stationary-context” condition and involved keeping the context at the same position during the whole trial (egocentric and/or allocentric coding). Condition 3 was a “moved-context” condition that involved shifting the context to a different location during the recall delay (allocentric coding). Movement accuracy and kinematics results were strikingly similar for the moved-context and stationary-context conditions. These results suggest that when both allocentric and egocentric coding are possible, an allocentric strategy is used.
Martin Lemay, Christopher P. Bertram and George E. Stelmach
Brianne L. Foulon, Valérie Lemay, Victoria Ainsworth and Kathleen A. Martin Ginis
The purpose of this study was to determine preferences of people with spinal cord injury (SCI) and health care professionals (HCP) regarding the content and format of a SCI physical activity guide to support recently released SCI physical activity guidelines. Seventy-eight people with SCI and 80 HCP completed a survey questionnaire. Participants with SCI identified desired content items and their preferences for format. HCP rated the helpfulness of content items to prescribe physical activity. All content items were rated favorably by participants with SCI and useful by HCP. The risks and benefits of activity and inactivity, and strategies for becoming more active, were rated high by both samples. Photographs and separate information for those with paraplegia versus tetraplegia were strongly endorsed. These data were used to guide the development of an SCI physical activity guide to enhance the uptake of physical activity guidelines for people with SCI. The guide was publically released November 11, 2011.