Sourav Suddha, Bottari Davide, Kekunnaya Ramesh, Röder Brigitte
Biological Psychology and Neuropsychology, University of Hamburg, Hamburg, Germany.
IMT School for Advanced Studies Lucca, Lucca, Italy.
J Vis. 2018 Mar 1;18(3):22. doi: 10.1167/18.3.22.
Numerous studies in visually deprived nonhuman animals have demonstrated sensitive periods for the functional development of the early visual cortex. However, in humans it is yet unknown which visual areas are shaped to which degree based on visual experience. The present study investigated the functional organization and processing capacities of early visual cortex in sight recovery individuals with either a history of congenital cataracts (CC) or late onset cataracts (developmental cataracts, DC). Visual event-related potentials (VERPs) were recorded to grating stimuli which were flashed in one of the four quadrants of the visual field. Participants had to detect rarely occurring grating orientations. The CC individuals showed the expected polarity reversal of the C1 wave between upper and lower visual field stimuli at the typical latency range. Since the C1 has been proposed to originate in the early retinotopic visual cortex, we concluded that one basic feature of the retinotopic organization, upper versus lower visual field organization, is spared in CC individuals. Group differences in the size and topography of the C1 effect, however, suggested a less precise functional tuning. The P1 wave, which has been associated with extrastriate visual cortex processing, was significantly attenuated in CC but not in DC individuals compared to typically sighted controls. The present study thus provides evidence for fundamental aspects of retinotopic processing in humans being independent of developmental vision. We suggest that visual impairments in sight recovery individuals may predominantly arise at higher cortical processing stages.
众多针对视觉剥夺的非人类动物的研究已经证明了早期视觉皮层功能发育的敏感期。然而，在人类中，基于视觉经验，哪些视觉区域会在何种程度上形成仍不清楚。本研究调查了有先天性白内障（CC）病史或迟发性白内障（发育性白内障，DC）的视力恢复个体早期视觉皮层的功能组织和处理能力。记录了对在视野四个象限之一中闪烁的光栅刺激的视觉事件相关电位（VERP）。参与者必须检测很少出现的光栅方向。CC个体在典型潜伏期范围内，上视野和下视野刺激之间的C1波出现了预期的极性反转。由于有人提出C1起源于早期视网膜拓扑视觉皮层，我们得出结论，视网膜拓扑组织的一个基本特征，即上视野与下视野组织，在CC个体中得以保留。然而C1效应的大小和拓扑结构的组间差异表明功能调谐不太精确。与正常视力对照组相比，与纹外视觉皮层处理相关的P1波在CC个体中显著衰减，但在DC个体中没有。因此，本研究为人类视网膜拓扑处理的基本方面独立于发育性视觉提供了证据。我们认为，视力恢复个体的视觉障碍可能主要出现在更高的皮层处理阶段。
