视觉空间处理障碍在患有脑视觉障碍(CVI)的个体中很普遍,通常归因于“背流功能障碍”(DSD)。然而,其他皮质区域的贡献,包括早期视觉皮层(EVC),额叶皮质,或者腹侧视觉流,这种损伤仍然未知。因此,在这里,我们检查了这些区域的功能磁共振成像活动,而具有CVI(和神经典型)的个体在动态自然场景中执行视觉搜索任务。首先,行为表现用眼动追踪测量。参与者被指示搜索并跟随行走的人类目标。CVI参与者需要更长的时间才能找到目标,他们的眼睛凝视模式不太准确,也不太精确。第二,我们在MRI扫描仪中使用了相同的任务。沿着背河,CVI参与者的激活减少,与CVI中建议的DSD一致。有趣的是,然而,沿腹侧溪流的视觉区域显示出完全相反的模式,在CVI参与者中具有更大的激活。相比之下,我们发现两组间EVC或额叶皮质无差异.这些结果表明,CVI中受损的视觉空间处理能力与背侧和腹侧视觉流的不同募集有关,可能是由于选择性注意力受损所致。
Visuospatial processing impairments are prevalent in individuals with cerebral visual impairment (CVI) and are typically ascribed to \"dorsal stream dysfunction\" (DSD). However, the contribution of other cortical regions, including early visual cortex (EVC), frontal cortex, or the ventral visual stream, to such impairments remains unknown. Thus, here, we examined fMRI activity in these regions, while individuals with CVI (and neurotypicals) performed a visual search task within a dynamic naturalistic scene. First, behavioral performance was measured with eye tracking. Participants were instructed to search and follow a walking human target. CVI participants took significantly longer to find the target, and their eye gaze patterns were less accurate and less precise. Second, we used the same task in the MRI scanner. Along the dorsal stream, activation was reduced in CVI participants, consistent with the proposed DSD in CVI. Intriguingly, however, visual areas along the ventral stream showed the complete opposite pattern, with greater activation in CVI participants. In contrast, we found no differences in either EVC or frontal cortex between groups. These results suggest that the impaired visuospatial processing abilities in CVI are associated with differential recruitment of the dorsal and ventral visual streams, likely resulting from impaired selective attention.