Cortical Response to Task-relevant Stimuli Presented outside the Primary Focus of Attention
Cortical Response to Task-relevant Stimuli Presented outside the Primary Focus of Attention
复制标题
DOI：
10.1162/jocn.2009.21327
复制
发表时间：
2010-09-01
影响因子：
3.2
通讯作者：
Braun, Jochen
中科院分区：
文献类型：
--
作者：
Houtkamp, Roos;Braun, Jochen
视觉注意选择性地增强对任务相关项目的神经反应。但是，当注意力的主要焦点之外的一个项目也与手头的任务相关时，会发生什么呢？在一个双任务fMRI实验中，我们研究了在这种情况下，视网膜组织的视觉皮层的反应。观察者在中央凹执行一项需要注意力的任务，而另一个未掩蔽的刺激出现在视觉周边。对于后一种刺激，观察者试图执行一个更少或更需要注意力的任务。这两项任务都增加了BOLD对外周刺激的反应。然而，从行为上看，只有要求不高的任务执行得很好，而要求高的任务执行得很好。什么可以解释BOLD反应和行为表现之间的差异？一个控制实验表明，报告的要求不高的功能受到严重干扰的面具。此外，视觉属性查询的高要求的任务有一个显着较短的图标记忆持久性。我们的结论是，在双任务的情况下，注意力的焦点最初仍然与中央凹任务，但随后转移到周边刺激的前位置。这种迟来的向外围图像记忆的转变（在一种情况下是无用的，在另一种情况下是有用的）将使类似的BOLD反应与不同的行为表现相协调。总之，我们的研究结果表明，增强的BOLD反应始终与注意力调节，但不与行为表现。
Visual attention selectively enhances the neural response to a task-relevant item. But what happens when an item outside the primary focus of attention is also relevant to the task at hand? In a dual-task fMRI experiment, we studied the responses in retinotopically organized visual cortex in such a situation. Observers performed an attention-demanding task in the fovea while another, unmasked stimulus appeared in the visual periphery. With respect to this latter stimulus, observers attempted to perform either a less or a more attentionally demanding task. Both tasks increased the BOLD response to the peripheral stimulus. Behaviorally, however, only the less demanding task was performed well, whereas the demanding task was carried out near chance. What could explain the discrepancy between BOLD response and behavioral performance? A control experiment revealed that the report of the less demanding feature was severely disturbed by a mask. Moreover, the visual attributes queried by the demanding task had a significantly shorter iconic memory persistence. We conclude that, in the dual-task situation, the focus of attention initially remains with the foveal task, but subsequently shifts to the former location of the peripheral stimulus. Such a belated shift to a peripheral iconic memory (futile in one case, informative in the other) would reconcile the similar BOLD response with the disparate behavioral performance. In summary, our results show that an enhanced BOLD response is consistently associated with attentional modulation, but not with behavioral performance.