Results 1 -
2 of
2
The Influence of ‘‘Blind’ ’ Distractors on Eye Movement Trajectories in Visual Hemifield Defects
"... & There is evidence that some visual information in blind regions may still be processed in patients with hemifield defects after cerebral lesions (‘‘blindsight’’). We tested the hypothesis that, in the absence of retinogeniculostriate processing, residual retinotectal processing may still be detect ..."
Abstract
-
Cited by 2 (1 self)
- Add to MetaCart
& There is evidence that some visual information in blind regions may still be processed in patients with hemifield defects after cerebral lesions (‘‘blindsight’’). We tested the hypothesis that, in the absence of retinogeniculostriate processing, residual retinotectal processing may still be detected as modifications of saccades to seen targets by irrelevant distractors in the blind hemifield. Six patients were presented with distractors in the blind and intact portions of their visual field and participants were instructed to make eye movements to targets in the intact field. Eye movements were recorded to determine if blind-field distractors caused deviation in saccadic trajectories. No deviation was found in one patient with an optic chiasm lesion, which affect both retinotectal and retinogeniculostriate pathways. In five patients with lesions of the optic radiations or the striate cortex, the results were mixed, with two of the five patients showing significant deviations of saccadic trajectory away from the ‘‘blind’ ’ distractor. In a second experiment, two of the five patients were tested with the target and the distractor more closely aligned. Both patients showed a ‘‘global effect,’ ’ in that saccades deviated toward the distractor, but the effect was stronger in the patient who also showed significant trajectory deviation in the first experiment. Although our study confirms that distractor effects on saccadic trajectory can occur in patients with damage to the retinogeniculostriate visual pathway but preserved retinotectal projections, there remain questions regarding what additional factors are required for these effects to manifest themselves in a given patient. &
Neural Activity within Area V1 Reflects Unconscious Visual Performance in a Case of Blindsight Abstract
"... & Although lesions of the striate (V1) cortex disrupt conscious vision, patients can demonstrate surprising residual abilities within their affected visual field, a phenomenon termed blindsight. The relative contribution of spared ‘‘islands’ ’ of functioning striate cortex to residual vision, versus ..."
Abstract
- Add to MetaCart
& Although lesions of the striate (V1) cortex disrupt conscious vision, patients can demonstrate surprising residual abilities within their affected visual field, a phenomenon termed blindsight. The relative contribution of spared ‘‘islands’ ’ of functioning striate cortex to residual vision, versus subcortical pathways to extrastriate areas, has implications for the role of early visual areas in visual awareness and performance. Here we describe the behavioral and neural features of residual cortical function in Patient M.C., who sustained a posterior cerebral artery stroke at the age of 15 years. Within her impaired visual field, we found preserved visual abilities characteristic of blindsight, including superior detection of motion, and above-chance discrimination

