Attentional modulation of MT neurons with single or multiple stimuli in their receptive fields.
Attentional modulation of MT neurons with single or multiple stimuli in their receptive fields.
复制标题
DOI：
10.1523/jneurosci.3766-09.2010
复制
发表时间：
2010-02-24
期刊：
影响因子：
--
通讯作者：
Maunsell JH
中科院分区：
文献类型：
--
作者：
Lee J;Maunsell JH
对注意力如何调节神经元反应的描述表明，其影响的强度取决于刺激条件。对单个神经元感受野中的孤立刺激的注意通常会适度增强细胞的反应，但当注意力在感受野内的多个刺激之间转移时，神经元反应通常会受到强烈调节。然而，之前的报告并未在同等条件下比较这些刺激效果，因此任务难度的差异可能是造成这种差异的主要原因。因此，刺激条件的定量效应仍然未知，并且不可能解决观察到的差异是否可以用单一机制解释的问题。我们使用任务设计测量了两只恒河猴 MT 区域 70 个单个神经元反应的注意力调节，该任务设计在不同的刺激配置下保持注意力稳定。我们发现，当接受域内有不止一种刺激时，注意力调节确实要强得多。然而，在不同条件下观察到的广泛的注意力调节可以很容易地用单一机制来解释。来自所有刺激条件的神经生理学数据都非常适合注意力通过反应标准化机制发挥作用的模型。总的来说，这些结果验证了之前关于刺激配置对注意力调节的影响的印象，并为注意力调节依赖于反应标准化机制的假设提供了支持。
Descriptions of how attention modulates neuronal responses suggest that the strength of its effects depends on stimulus conditions. Attention to an isolated stimulus in the receptive field of an individual neuron typically produces a moderate enhancement of the cell's response, but neuronal responses are often strongly modulated when attention is shifted between multiple stimuli that lie within the receptive field. However, previous reports have not compared these stimulus effects under equivalent conditions, so differences in task difficulty could have been responsible for much of the difference. Consequently, the quantitative effects of stimulus conditions have remained unknown, and it has not been possible to address the question of whether the differences that have been observed could be explained by a single mechanism. We measured the attentional modulation of the responses of 70 single neurons in area MT of two rhesus monkeys using a task design that kept attention stable across different stimulus configurations. We found that attentional modulation was indeed much stronger when more than one stimulus was within the receptive field. Nevertheless, the broad range of attentional modulations seen across the different conditions could be readily explained by single mechanism. The neurophysiological data from all stimulus conditions were well fit by a model in which attention acts through a response normalization mechanism. Collectively, these results validate previous impressions of the effects of stimulus configuration on attentional modulation, and add support to hypothesis that attention modulation depends on a response normalization mechanism.