Howard Christina J, Bashir Naheem, Chechlacz Magdalena, Humphreys Glyn W
Division of Psychology, Chaucer Building, Nottingham Trent University, Burton Street, Nottingham NG1 4BU, UK School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK Division of Psychology and Language Sciences, University College London, Gower Street, London WC1E 6BT.
Cereb Cortex. 2016 Jul;26(7):2952-69. doi: 10.1093/cercor/bhv101. Epub 2015 Jun 1.
The dynamic nature of the world requires that our visual representations are continuously updated. These representations are more precise if there is a narrow time window over which information is averaged. We assess the neural processes of visual updating by testing patients with lesions including inferior parietal cortex, control patients and healthy adults on a continuous visual monitoring task. In Experiment 1, observers kept track of the changing spatial period of a luminance grating and identified the final spatial period after the stimulus disappeared. Healthy older adults and neurological controls were able to perform better than simulated guesses, but only 3 of 11 patients with damage including parietal cortex were able to reach performance that differed from simulated guesses. The effects were unrelated to lesion size. Poor performance on this task is consistent with an inability to selectively attend to the final moment at which the stimulus was seen. To investigate the temporal limits of attention, we varied the rate of stimulus change in Experiment 2. Performance remained poor for some patients even with slow 2.5 Hz change rates. The performance of 4 patients with parietal damage displayed poor temporal precision, namely recovery of performance with slower rates of change.
世界的动态特性要求我们的视觉表征不断更新。如果存在一个信息被平均的狭窄时间窗口，这些表征会更精确。我们通过在连续视觉监测任务中测试患有包括顶下叶皮质损伤的患者、对照患者和健康成年人，来评估视觉更新的神经过程。在实验1中，观察者跟踪亮度光栅不断变化的空间周期，并在刺激消失后识别最终的空间周期。健康的老年人和神经学对照者能够比模拟猜测表现得更好，但在11名患有包括顶叶皮质损伤的患者中，只有3人能够达到与模拟猜测不同的表现。这些影响与损伤大小无关。在这项任务上表现不佳与无法选择性地关注看到刺激的最后时刻是一致的。为了研究注意力的时间限制，我们在实验2中改变了刺激变化的速率。即使在2.5赫兹的缓慢变化速率下，一些患者的表现仍然很差。4名患有顶叶损伤的患者的表现显示出较差的时间精度，即随着变化速率变慢表现有所恢复。
