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Pointing to two imaginary targets at the same time: Bimanual allocentric and egocentric localization in visual form agnosic D.F

Carey, D.P.; Dijkerman, H.C.; Milner, A.D.

Pointing to two imaginary targets at the same time: Bimanual allocentric and egocentric localization in visual form agnosic D.F Thumbnail


Authors

D.P. Carey

H.C. Dijkerman

A.D. Milner



Abstract

We have previously shown the visual form agnosic patient D.F. has spared sensorimotor utilization of visual information relative to her poor perceptual processing of the same stimulus attributes. Her visuomotor skills are, however, only normal when egocentric visual coding can be used in the task. In other words, her egocentric sensorimotor processing is intact while her ‘allocentric’ coding of spatial position is impaired. The current investigation extends these previous observations by comparing D.F.’s performance in bimanual pointing to pairs of stimuli directly (the egocentric task) versus pointing to the homologous positions on an adjacent workspace (pantomimed reaching, the allocentric task). The results showed greatly superior pointing accuracy in direct pointing compared to pantomimed pointing. The mechanisms supporting her limited but remaining sensitivity to spatial relationships during pantomimed pointing remain unknown. These residual skills may reflect partially spared categorical coding and/or internal sensorimotor self-cueing.

Citation

Carey, D., Dijkerman, H., & Milner, A. (2009). Pointing to two imaginary targets at the same time: Bimanual allocentric and egocentric localization in visual form agnosic D.F. Neuropsychologia, 47(6), 1469-1475. https://doi.org/10.1016/j.neuropsychologia.2009.02.001

Journal Article Type Article
Publication Date May 1, 2009
Deposit Date Oct 8, 2009
Publicly Available Date Mar 28, 2024
Journal Neuropsychologia
Print ISSN 0028-3932
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 47
Issue 6
Pages 1469-1475
DOI https://doi.org/10.1016/j.neuropsychologia.2009.02.001
Keywords Visual form agnosia, Two visual systems, Bimanual aiming, Spatial processing: allocentric, Egocentric.

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