Reward- and Attention-related Biasing of Sensory Selection in Visual Cortex
Reward- and Attention-related Biasing of Sensory Selection in Visual Cortex
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DOI：
10.1162/jocn_a_00539
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发表时间：
2014-05-01
影响因子：
3.2
通讯作者：
Hopf, Jens-Max
中科院分区：
文献类型：
--
作者：
Buschschulte, Antje;Boehler, Carsten N.;Hopf, Jens-Max
对任务相关特征的关注导致层外皮层感觉选择的偏倚。信号奖励的特征似乎产生了类似的偏见，但奖励和注意力的调节作用是如何相互关联的，这在很大程度上还没有被探索。为了解决这个问题，我们必须将自上而下的设置从定义注意力的设置中分离出来。为此，我们使用了一种视觉搜索范式，通过在搜索框架上提供金钱奖励，将目标的定义（对颜色的注意）与奖励相关性分离开来，在搜索框架上，某种与任务无关的颜色与目标定义的颜色结合起来，形成目标物体。我们通过分析在目标定义颜色、奖励相关颜色和完全不相关的颜色作为参考中绘制的异步呈现的不相关分心物探针的神经磁脑反应，评估了参与和奖励相关颜色的神经偏置状态。我们观察到，对于中度奖励的前景，目标定义颜色而不是奖励相关颜色在180 - 280毫秒的腹侧纹外视觉皮层中选择性地增强了神经磁反应。奖励预期的增加导致奖赏探针反应的延迟衰减（220-250毫秒），这是在前一个（160-180毫秒）的反应增强之后。值得注意的是，ACC背侧较短的潜伏期反应与层外视觉皮层较强的衰减有关。最后，对大脑对搜索框架的反应的分析表明，搜索干扰物中与奖励相关的颜色的存在引起了一种增强的反应，这种反应在增加奖励大小后被消除。这些数据共同表明，当自上而下的奖励相关性和注意定义分离时，奖励相关特征的行为意义仍然在较高水平的皮层区域快速编码，从而指挥有效的自上而下抑制控制，以对抗外皮层对这些特征的选择偏差。
Attention to task-relevant features leads to a biasing of sensory selection in extrastriate cortex. Features signaling reward seem to produce a similar bias, but how modulatory effects due to reward and attention relate to each other is largely unexplored. To address this issue, it is critical to separate top-down settings defining reward relevance from those defining attention. To this end, we used a visual search paradigm in which the target's definition (attention to color) was dissociated from reward relevance by delivering monetary reward on search frames where a certain task-irrelevant color was combined with the target-defining color to form the target object. We assessed the state of neural biasing for the attended and reward-relevant color by analyzing the neuromagnetic brain response to asynchronously presented irrelevant distractor probes drawn in the target-defining color, the reward-relevant color, and a completely irrelevant color as a reference. We observed that for the prospect of moderate rewards, the target-defining color but not the reward-relevant color produced a selective enhancement of the neuromagnetic response between 180 and 280 msec in ventral extrastriate visual cortex. Increasing reward prospect caused a delayed attenuation (220-250 msec) of the response to reward probes, which followed a prior (160-180 msec) response enhancement in dorsal ACC. Notably, shorter latency responses in dorsal ACC were associated with stronger attenuation in extrastriate visual cortex. Finally, an analysis of the brain response to the search frames revealed that the presence of the reward-relevant color in search distractors elicited an enhanced response that was abolished after increasing reward size. The present data together indicate that when top-down definitions of reward relevance and attention are separated, the behavioral significance of reward-associated features is still rapidly coded in higher-level cortex areas, thereby commanding effective top-down inhibitory control to counter a selection bias for those features in extrastriate visual cortex.