Prestimulus Oscillatory Activity over Motor Cortex Reflects Perceptual Expectations
Prestimulus Oscillatory Activity over Motor Cortex Reflects Perceptual Expectations
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DOI：
10.1523/jneurosci.1094-12.2013
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发表时间：
2013-01-23
影响因子：
5.3
通讯作者：
Lau, Hakwan
中科院分区：
文献类型：
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作者：
de Lange, Floris P.;Rahnev, Dobromir;Lau, Hakwan
当感知决策与特定效应器耦合时，预备运动皮质活动可能会提供一个了解感知选择动态的窗口。具体来说，以前的研究已经观察到随着时间的推移，运动区域的选择选择性活动的积累反映了视觉皮层提供的综合感觉证据。在这里，我们问如何选择性的运动活动是由先前的期望在视觉运动辨别任务的修改。决策制定的计算模型将决策形式化为从起点到决策界限的证据积累。在这个框架内，预期可以改变起点、积累率或决策界限。使用人类观察者的脑磁图，我们专门测试了运动皮层选择性振荡活动起点的变化。诱导对运动方向的先验期望偏向被试的知觉判断以及刺激开始前8 - 30 Hz频率范围内的选择性运动活动;这些行为和神经偏向的个体强度在被试之间存在相关性。在没有明确的期望线索，自发偏见的选择性活动是明显的运动皮层。这些也预测了最终的知觉选择，至少部分是由前一次试验的选择引起的。我们的结论是，内源性和明确诱导的知觉预期偏见的起点决策相关的活动，在感官证据的积累。
When perceptual decisions are coupled to a specific effector, preparatory motor cortical activity may provide a window into the dynamics of the perceptual choice. Specifically, previous studies have observed a buildup of choice-selective activity in motor regions over time reflecting the integrated sensory evidence provided by visual cortex. Here we ask how this choice-selective motor activity is modified by prior expectation during a visual motion discrimination task. Computational models of decision making formalize decisions as the accumulation of evidence from a starting point to a decision bound. Within this framework, expectation could change the starting point, rate of accumulation, or the decision bound. Using magneto-encephalography in human observers, we specifically tested for changes in the starting point in choice-selective oscillatory activity over motor cortex. Inducing prior expectation about motion direction biased subjects' perceptual judgments as well as the choice-selective motor activity in the 8 - 30 Hz frequency range before stimulus onset; the individual strength of these behavioral and neural biases were correlated across subjects. In the absence of explicit expectation cues, spontaneous biases in choice-selective activity were evident over motor cortex. These also predicted eventual perceptual choice and were, at least in part, induced by the choice on the previous trial. We conclude that both endogenous and explicitly induced perceptual expectations bias the starting point of decision-related activity, before the accumulation of sensory evidence.