Popple Ariella V, Levi Dennis M
School of Optometry and Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA, USA.
J Vis. 2008 Oct 31;8(13):12.1-9. doi: 10.1167/8.13.12.
Amblyopia is a disorder of visual acuity in one eye, thought to arise from suppression by the other eye during development of the visual cortex. In the attentional blink, the second of two targets (T2) in a Rapid Serial Visual Presentation (RSVP) stream is difficult to detect and identify when it appears shortly but not immediately after the first target (T1). We investigated the attentional blink seen through amblyopic eyes and found that it was less finely tuned in time than when the 12 amblyopic observers viewed the stimuli with their preferred eyes. T2 performance was slightly better through amblyopic eyes two frames after T1 but worse one frame after T1. Previously (A. V. Popple & D. M. Levi, 2007), we showed that when the targets were red letters in a stream of gray letters (or vice versa), normal observers frequently confused T2 with the letters before and after it (neighbor errors). Observers viewing through their amblyopic eyes made significantly fewer neighbor errors and more T2 responses consisting of letters that were never presented. In normal observers, T1 (on the rare occasions when it was reported incorrectly) was often confused with the letter immediately after it. Viewing through their amblyopic eyes, observers with amblyopia made more responses to the letter immediately before T1. These results suggest that childhood suppression of the input from amblyopic eyes disrupts attentive processing. We hypothesize reduced connectivity between monocularly tuned lower visual areas, subcortical structures that drive foveal attention, and more frontal regions of the brain responsible for letter recognition and working memory. Perhaps when viewing through their amblyopic eyes, the observers were still processing the letter identity of a prior distractor when the color flash associated with the target was detected. After T1, unfocused temporal attention may have bound together erroneously the features of succeeding letters, resulting in the appearance of letters that were not actually presented. These findings highlight the role of early (monocular) visual processes in modulating the attentional blink, as well as the role of attention in amblyopic visual deficits.
弱视是一只眼睛的视力障碍，被认为是在视觉皮层发育过程中由另一只眼睛的抑制作用引起的。在注意瞬脱中，快速序列视觉呈现（RSVP）流中的两个目标（T2）中的第二个目标，当它在第一个目标（T1）之后不久但不是紧接着出现时，很难被检测和识别。我们研究了通过弱视眼观察到的注意瞬脱，发现其在时间上的精细调节不如12名弱视观察者用他们的优势眼观察刺激时那样。T2的表现，在T1之后两帧时通过弱视眼观察略好，但在T1之后一帧时则较差。之前（A.V.波普尔和D.M.利维，2007年），我们表明，当目标是灰色字母流中的红色字母时（反之亦然），正常观察者经常将T2与它前后的字母混淆（相邻错误）。通过弱视眼观察的观察者产生的相邻错误明显较少，并且更多的T2反应是由从未呈现过的字母组成。在正常观察者中，T1（在极少数被错误报告的情况下）经常与它后面紧接着的字母混淆。通过弱视眼观察时，弱视观察者对紧接在T1之前的字母有更多反应。这些结果表明，儿童期对弱视眼输入的抑制会扰乱注意力加工。我们假设，单眼调节的较低视觉区域、驱动中央凹注意力的皮层下结构以及大脑中负责字母识别和工作记忆的更多额叶区域之间的连接性降低。也许当通过弱视眼观察时，观察者在检测到与目标相关的颜色闪光时仍在处理先前干扰物的字母身份。在T1之后，注意力不集中可能错误地将后续字母的特征结合在一起，导致出现实际上未呈现的字母。这些发现突出了早期（单眼）视觉过程在调节注意瞬脱中的作用，以及注意力在弱视视觉缺陷中的作用。
