Unilateral damage to post-chiasmatic visual pathways or cortical areas results in the loss of vision in the contralateral hemifield, known as hemianopia. Some patients, however, may retain the ability to perform an above chance unconscious detection or discrimination of visual stimuli presented to the blind hemifield, known as “blindsight”. An important finding in blindsight research is that it can often be elicited by moving stimuli. Therefore, in the present study, we wanted to test whether moving stimuli might yield blindsight phenomena in patients with cortical lesions resulting in hemianopia, in a discrimination task where stimulus movement is orthogonal to the feature of interest. This could represent an important strategy for rehabilitation because it might improve discrimination ability of stimulus features different but related to movement, e.g. line orientation.

We tested eight hemianopic patients and eight age-matched healthy controls in an orientation discrimination task with moving or static visual stimuli. During performance of the task we carried out fMRI scanning and tractography. Behaviourally, we did not find a reliable main effect of motion on orientation discrimination; however, an important result was that in different patients blindsight could occur only with moving or stationary stimuli or with both. As to brain imaging results, following presentation of moving stimuli to the blind hemifield, a widespread fronto-parietal bilateral network was recruited including areas of the dorsal stream and in particular bilateral motion area hMT + whose activation positively correlated with behavioural performance. This bilateral network was not activated in controls suggesting that it represents a compensatory functional change following brain damage. Moreover, there was a higher activation of ipsilesional area hMT+ in patients who performed above chance in the moving condition. By contrast, in patients who performed above chance in the static condition, we found a higher activation of contralesional area V1 and extrastriate visual areas. Finally, we found a linear relationship between structural integrity of the ipsilesional pathway connecting lateral geniculate nucleus (LGN) with motion area hMT+ and both behavioural performance and ipsilesional hMT + activation. These results support the role of LGN in modulating performance as well as BOLD amplitude in the absence of visual awareness in ipsilesional area hMT+ during an orientation discrimination task with moving stimuli.

chi行后视路或皮层区的单侧损伤会导致对侧半视野（称为偏盲）的视力丧失。但是，某些患者可能会保留对盲人半视野中出现的视觉刺激进行无意识检测或辨别的能力，称为“盲视”。视力研究的一个重要发现是，通常可以通过移动刺激来激发它。因此，在本研究中，我们想测试在刺激运动与目标特征正交的判别任务中，运动刺激是否会在导致偏瘫的皮质病变患者中产生盲目现象。

我们通过运动或静态视觉刺激在定向识别任务中测试了八名偏盲患者和八名年龄匹配的健康对照者。在执行任务的过程中，我们进行了功能磁共振成像扫描和超声检查。行为上，我们没有发现运动对方向识别的可靠的主要影响。然而，一个重要的结果是，在不同的患者中，视力仅可能在运动或静止刺激或两者同时发生时发生。关于脑成像结果，在将刺激移至盲半球后，招募了广泛的额顶双边网络，包括背流区域，尤其是双边运动区域hMT +，其激活与行为表现呈正相关。该双边网络未在对照中激活，表明它代表脑损伤后的代偿性功能变化。此外，在运动条件下表现出较高机会的患者中，患处hMT +的活化更高。相比之下，在静态条件下机率较高的患者中，我们发现对侧区V1和视线上方区的激活更高。最后，我们发现连接外侧膝状核（LGN）与运动区域hMT +的同侧通路的结构完整性与行为表现和同侧hMT +激活之间存在线性关系。