Neuroscience 2005 Abstract
| Presentation Number: | 989.5 |
|---|---|
| Abstract Title: | Appearance of a new object in the visual field increases pointing errors in subjects with parietal lobe lesions. |
| Authors: |
Darling, W. G.*1
; Viaene, A. N.1
; Bartelt, R. B.1
; Vecera, S. P.3
; Rizzo, M.2
1Dept Exercise Sci, Univ. of Iowa, Iowa City, IA 2Neurology, Univ. of Iowa, Iowa City, IA 3Psychology, Univ. of Iowa, Iowa City, IA |
| Primary Theme and Topics |
Sensory and Motor Systems - Kinematics and EMG -- Reaching and pointing |
| Session: |
989. Kinematics and EMG: Reaching and Pointing II Poster |
| Presentation Time: | Wednesday, November 16, 2005 1:00 PM-2:00 PM |
| Location: | Washington Convention Center - Hall A-C, Board # GG27 |
| Keywords: | hand, movement, vision |
Eye movements to a visual target are disrupted by the appearance of a task-irrelevant object in the visual field such that gaze is captured by that object unless there is sufficient time to focus attention on the target(Theeuwes et al. 1998, Psych Sci 4:379). Previously, we showed that hand movements of healthy young adults were minimally disturbed in a non-specific manner by objects suddenly appearing in the visual field (Darling et al. 2004. SFN Abstracts 30:995.12). We asked here whether hand movements by subjects with unilateral lesions of posterior parietal lobule (PPL) are attracted by the sudden appearance of new objects. We employed a paradigm similar to that used previously and recorded hand movements to targets using a touch-screen mounted on a horizontal table about 25 cm below the computer display. Briefly, 19 subjects (age 24-76 years) with brain lesions (11 with lesions of PPL, 8 with lesions outside PPL) and 10 healthy adults of similar age viewed a central blue fixation dot surrounded by six gray circles (equally spaced on an imaginary circle) containing a black figure-eight premask. After 1 s all but one of the surrounding circles changed to red and the premasks changed to letters for a period of 200 ms, followed by a blank display. Subjects moved the preferred hand to the remaining gray circle as quickly as possible. On one half of the trials an additional red circle (distracter) appeared in one of six locations (equally spaced between the other circles). We found that subjects with left PPL lesions made larger errors than controls, especially when new objects appeared, but the hand was not attracted toward the new object. In contrast, subjects with right PPL lesions were less affected by appearance of new objects and made smaller errors than subjects with left PPL lesions. Thus, left PPL damage impairs ability to deal with appearance of new objects in the visual field, but the hand is not attracted to move toward the new object.
Supported by NIH grant P01 NS 19632
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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