V1 Projection Zone Signals in Human Macular Degeneration Depend on Task, not Stimulus
V1 Projection Zone Signals in Human Macular Degeneration Depend on Task, not Stimulus
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DOI：
10.1093/cercor/bhm256
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发表时间：
2008-11-01
期刊：
影响因子：
3.7
通讯作者：
Wandell, Brian A.
中科院分区：
文献类型：
--
作者：
Masuda, Yoichiro;Dumoulin, Serge O.;Wandell, Brian A.
我们使用功能磁共振成像来评估患有青少年黄斑变性（JMD）的人类的异常皮质信号。这些信号被解释为表明大规模的皮质重组。受试者被动地观看刺激或执行任务；该任务与刺激相关或无关。在被动观看或执行与刺激无关的任务时，存在大量无反应的 V1 区域。这些区域包括中心凹投影区，我们将它们称为病变投影区（LPZ）。在 3 名 JMD 受试者中，我们观察到他们在进行刺激相关判断时 LPZ 出现了高度显着的反应。在对照组中，我们仅在周边视野内呈现刺激，在任何条件下，中央凹投影区都没有 V1 反应。 JMD 和对照反应之间的差异可以通过对 V1 重组具有非常不同影响的假设来解释。在对照中，视网膜传入信号携带指示视野中存在均匀（零对比度）区域的信号。视网膜输入的删除可能1）刺激携带任务依赖性信号（重组）的新皮层通路的形成，或2）揭露通常被删除信号抑制的先前存在的任务依赖性皮层信号（无重组）。
We used functional magnetic resonance imaging to assess abnormal cortical signals in humans with juvenile macular degeneration (JMD). These signals have been interpreted as indicating large-scale cortical reorganization. Subjects viewed a stimulus passively or performed a task; the task was either related or unrelated to the stimulus. During passive viewing, or while performing tasks unrelated to the stimulus, there were large unresponsive V1 regions. These regions included the foveal projection zone, and we refer to them as the lesion projection zone (LPZ). In 3 JMD subjects, we observed highly significant responses in the LPZ while they performed stimulus-related judgments. In control subjects, where we presented the stimulus only within the peripheral visual field, there was no V1 response in the foveal projection zone in any condition. The difference between JMD and control responses can be explained by hypotheses that have very different implications for V1 reorganization. In controls retinal afferents carry signals indicating the presence of a uniform (zero-contrast) region of the visual field. Deletion of retinal input may 1) spur the formation of new cortical pathways that carry task-dependent signals (reorganization), or 2) unmask preexisting task-dependent cortical signals that ordinarily are suppressed by the deleted signals (no reorganization).