Neuroscience 2005 Abstract
| Presentation Number: | 642.5 |
|---|---|
| Abstract Title: | Priming and the role of attention in hemispatial neglect. |
| Authors: |
Van Vleet, T. M.*1,2
; Robertson, L. C.1,2
1Neuroscience, Univ. of California, Berkeley, Berkeley, CA 2CA, 424 Yale Ave, 94708, |
| Primary Theme and Topics |
Cognition and Behavior - Human Cognition, Behavior, and Anatomy -- Attention |
| Session: |
642. Attention IV Poster |
| Presentation Time: | Tuesday, November 15, 2005 8:00 AM-9:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # FF7 |
| Keywords: | attention, neglect, binding, vision |
Feature integration theory maintains the necessity of attention in binding feature elements to form an accurate perception of a target consisting of conjoined features. Hemispatial neglect provides a unique opportunity to examine this theory in the context of a profound attention deficit. The current experiment examined the effectiveness of a prime consisting of a conjunction that matched a subsequent target (red triangle) vs. a prime consisting of a disjunction of relevant target features (blue triangles and red squares). A psychophysical staircase method (Kaernbach, 1990) was used to vary presentation duration of the prime displays (circular arrays) to produce 75% and 25% detection accuracy. Thresholds to detect a target in the left or neglected visual field were tracked (eye movements were monitored and search items were equidistant from the point of fixation). These thresholds were used as the durations of the primes in the subsequent priming experiment. Primes consisting of either target-related conjunctions or target-related disjunctions were randomly shown for one of the two durations (25% detection or 75% detection) on each trial. In addition, a neutral prime consisting of features that did not share any relation with the target was randomly interspersed at the same exposure durations as the other primes to provide an adequate control. After prime offset, the probe was presented at the center of the screen (red triangle or organge circle). A speeded response was acquired indicating “yes” or “no” if the target was present or not. The results demonstrate that there is no benefit of conjoined features that match the target compared to disjoined features of the target when they are presented at low levels of awareness (25%). However, when the patient is more aware of the conjunction of features (75%), conjunction priming is more effective on target detection than disjunction priming. The results support the notion that attention is necessary for the accurate conjunction of features in hemispatial neglect.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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