The 'Sprague Effect' described in the seminal paper of James Sprague (Science 153:1544-1547, 1966a) is an unexpected paradoxical effect in which a second brain lesion reversed functional deficits induced by an earlier lesion. It was observed initially in the cat where severe and permanent contralateral visually guided attentional deficits generated by the ablation of large areas of the visual cortex were reversed by the subsequent removal of the superior colliculus (SC) opposite to the cortical lesion or by the splitting of the collicular commissure. Physiologically, this effect has been explained in several ways-most notably by the reduction of the functional inhibition of the ipsilateral SC by the contralateral SC, and the restoration of normal interactions between cortical and midbrain structures after ablation. In the present review, we aim at reappraising the 'Sprague Effect' by critically analyzing studies that have been conducted in the feline and human brain. Moreover, we assess applications of the 'Sprague Effect' in the rehabilitation of visually guided attentional impairments by using non-invasive therapeutic approaches such as transcranial magnetic stimulation (TMS) and transcranial direct-current stimulation (tDCS). We also review theoretical models of the effect that emphasize the inhibition and balancing between the two hemispheres and show implications for lesion inference approaches. Last, we critically review whether the resulting inter-hemispheric rivalry theories lead toward an efficient rehabilitation of stroke in humans. We conclude by emphasizing key challenges in the field of 'Sprague Effect' applications in order to design better therapies for brain-damaged patients.

中文翻译：

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视觉空间功能的摄动驱动悖论促进：重新审视“斯普拉效应”。

James Sprague的开创性论文中描述的“ Sprague效应”（科学153：1544-1547，1966a）是一种意想不到的自相矛盾的效应，其中第二脑部病变逆转了由早期病变引起的功能缺陷。最初在猫中观察到，猫的消融是由大面积的视皮层消融而产生的严重而永久的对侧视觉引导的注意力缺陷，随后通过切除与皮层病变相对的上丘（SC）或通过裂开而逆转关节合缝。从生理上讲，已通过多种方式解释了这种作用，最主要的是通过减少对侧SC对同侧SC的功能抑制以及消融后皮质与中脑结构之间正常相互作用的恢复。在目前的评论中，我们旨在通过批判性地分析在猫和人脑中进行的研究来重新评估“斯普拉效应”。此外，我们通过使用非侵入性治疗方法，例如经颅磁刺激（TMS）和经颅直流电刺激（tDCS），来评估“斯普拉效应”在视觉引导的注意力障碍康复中的应用。我们还回顾了影响的理论模型，该模型强调了两个半球之间的抑制和平衡，并显示了病灶推断方法的含义。最后，我们批判性地回顾了由此产生的半球间竞争理论是否导致了人类中风的有效康复。最后，我们着重强调“斯普拉效应”领域的主要挑战