Verleger Rolf, Heide Wolfgang, Kömpf Detlef
Department of Neurology, Medical University of Lübeck, 23538 Lübeck, Germany.
Exp Brain Res. 2002 May;144(1):17-29. doi: 10.1007/s00221-002-1021-0. Epub 2002 Mar 6.
Response delays of hemi-neglect patients to invalidly cued left targets in Posner's visual cueing task have been interpreted as reflecting disorders of covert attention, although shifts of overt attention have so far not been systematically measured in patients performing this task. Therefore, we measured saccades (i.e., fast goal-directed eye movements) induced by cues and targets in this task in ten patients with lesions of the right posterior parietal cortex and in age-matched healthy subjects. Participants were not aware that their saccades were studied. Of greatest interest was whether the presence or absence of saccades would modify the patients' response delay with invalidly cued left targets. In both groups, saccades occurred in many trials, key-press responses were slower in saccade trials than in no-saccade trials, and the delay by invalid cues was larger in saccade trials. The patients' responses were in particular delayed if preceded by saccades to the left. Their delay to invalidly cued left targets almost doubled (144 ms vs 76 ms) when only saccade trials were analyzed compared to when only no-saccade trials were analyzed. Thus, overt shifts (saccades) have a similar but larger effect on manual responses than covert shifts of attention. In particular, overt shifts make a considerable contribution to the patients' pathological delay of responses to invalidly cued left targets.
在波斯纳视觉线索任务中，半侧空间忽视患者对无效提示的左侧目标的反应延迟被解释为反映了隐蔽注意的障碍，尽管到目前为止，在执行该任务的患者中尚未系统测量过外显注意的转移。因此，我们测量了10名右侧后顶叶皮质受损患者和年龄匹配的健康受试者在该任务中由线索和目标诱发的扫视（即快速的目标导向性眼球运动）。参与者并未意识到他们的扫视正在被研究。最令人感兴趣的是扫视的出现与否是否会改变患者对无效提示的左侧目标的反应延迟。在两组中，许多试验中都出现了扫视，按键反应在有扫视的试验中比在无扫视的试验中更慢，并且在有扫视的试验中无效线索导致的延迟更大。如果之前有向左的扫视，患者的反应尤其会延迟。与仅分析无扫视试验相比，仅分析有扫视试验时，他们对无效提示的左侧目标的延迟几乎翻倍（144毫秒对76毫秒）。因此，外显转移（扫视）对手动反应的影响与隐蔽注意转移相似但更大。特别是，外显转移对患者对无效提示的左侧目标的病理性反应延迟有相当大的影响。
