Goal-driven selective attention in patients with right hemisphere lesions: how intact is the ipsilesional field?

Snow, JC and Mattingley, JB (2006) Goal-driven selective attention in patients with right hemisphere lesions: how intact is the ipsilesional field?. Brain, 129 168-181. doi:10.1093/brain/awh690


Author Snow, JC
Mattingley, JB
Title Goal-driven selective attention in patients with right hemisphere lesions: how intact is the ipsilesional field?
Journal name Brain   Check publisher's open access policy
ISSN 0006-8950
Publication date 2006-01-01
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1093/brain/awh690
Volume 129
Start page 168
End page 181
Total pages 14
Place of publication Oxford
Publisher Oxford Univ Press
Language eng
Abstract Patients with right hemisphere (RH) lesions often display a spatial bias in attention towards the ipsilesional hemifield. The behavioural manifestations of this spatial bias are typically interpreted as reflecting increased or enhanced attention for stimuli within the 'intact' ipsilesional field, and impaired attentional functioning within the contralesional field. In the healthy brain, goal-driven and stimulus-driven attentional processes interact to determine which stimuli should be prioritized for selection. Although unilateral brain damage increases the relative attentional salience of stimuli within the ipsilesional field, it might also cause problems in filtering or attenuating task-irrelevant information. We examined whether goal-driven attention modulates the processing of ipsilesional and contralesional information in 6 patients with unilateral brain damage following RH stroke (5 male, 1 female; mean age 60.8 years) and a group of age and sex-matched controls. We used a flanker task in which participants made speeded judgements on a central target item (a coloured letter). On each trial the target was flanked by a coloured letter in the left and right hemifields. In separate blocks, participants were instructed to judge either the identity or the colour of the central target and to ignore the flankers. The flanker on one side could be congruent, incongruent or neutral with respect to the target, on either the letter or the colour dimension, whereas the flanker on the other side was always neutral on both dimensions. Healthy controls showed significant interference from incongruent flankers on either side. Crucially, however, this effect only occurred for the task-relevant dimension [F(2,10) = 24.60; P < 0.001]. For patients, however, both the task-relevant and task-irrelevant dimensions of ipsilesional flankers interfered with response times [task-relevant: F(2,10) = 7.50, P < 0.05; task-irrelevant: F(1,5) = 6.20, P < 0.05]. Conversely, contralesional flankers influenced response times only when the target and distractor were incongruent on the task-relevant dimension [F(2,10) = 4.85; P < 0.05]. Our findings demonstrate that following RH damage, goal-driven biases cannot constrain the processing of task-irrelevant features of ipsilesional stimuli. We speculate that a lateralized bias in spatial attention leads to unselective prioritization of all feature-based attributes of stimuli appearing within the ipsilesional hemifield, whether or not they are relevant to performance. Attentional selection for ipsilesional stimuli in disorders such as spatial neglect and extinction may not therefore be entirely normal, as previously assumed.
Keyword Clinical Neurology
Neurosciences
spatial extinction
selectivity
goal-driven
stimulus-driven
feature-based selection
Posterior Parietal Cortex
Lateral Intraparietal Area
Unilateral Visual Neglect
Hemispatial Neglect
Spatial Neglect
Top-down
Prefrontal Cortex
Perceptual Load
Single Neurons
Bottom-up
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes This document is a journal review.

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: Excellence in Research Australia (ERA) - Collection
Queensland Brain Institute Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 34 times in Thomson Reuters Web of Science Article | Citations
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Created: Thu, 18 Oct 2007, 00:22:20 EST