Parallel interhemispheric processing in hemineglect: relation to visual field defects.
Parallel interhemispheric processing in hemineglect: relation to visual field defects.
复制标题
半球忽视的并行半球间处理：与视野缺陷的关系。
DOI：
10.1016/j.neuropsychologia.2009.04.014
复制
发表时间：
2009
期刊：
影响因子：
2.6
通讯作者：
Sabel,BernhardA
中科院分区：
文献类型：
--
作者：
Muller-Oehring,EvaM;Schulte,Tilman;Kasten,Erich;Poggel,DorotheA;Muller,Iris;Wustenberg,Torsten;Sabel,BernhardA
Parallel interhemispheric processing is required to explore our visual environment and to integrate visual information from both hemifields simultaneously. Damage to the right temporo-parietal cortex can disrupt such parallel processes and result in neglect and visual extinction of stimuli in the left contralesional visual space. Neglected or extinguished stimuli can still be processed, yet without reaching the patient's awareness. Such unconscious processing has been attributed to structurally intact primary visual areas in neglect. To study whether unconscious parallel processing depends on visual functional integrity, we compared the performance of neglect patients with visual field defects (VFDs) (n=11) and hemianopic patients with partial or complete blindness of one visual hemifield (n=11) on redundant targets effects (RTE). The RTE manifests as faster reaction times to redundant paired (two stimuli, one in each hemifield) than single stimulation (in one hemifield). We found RTEs, i.e., unconscious processing, in neglect patients but not in hemianopic patients. Furthermore, neglect patients showed large crossed–uncrossed differences (CUDs), i.e., faster response times to ipsi- than contralesional hemifield stimulation, reflecting a difference in processing speed for single stimuli in the two hemispheres that were correlated with VFDs and visual extinction. The finding that extinction, but not RTE, was correlated with the CUD suggests that under competitive bilateral stimulus conditions the delayed contralesional visual field input may not be detected by the intact left hemisphere, which presumably mediates the task given the impairment of the right hemisphere. By contrast, unconscious parallel processing of contralesional stimuli (RTE) occurred even when contralesional visual field input is lacking (VFD) or delayed (CUD) and is possibly mediated via subcortical visual pathways.
