Distinct relationships of parietal and prefrontal cortices to evidence accumulation.
Distinct relationships of parietal and prefrontal cortices to evidence accumulation.
复制标题
DOI：
10.1038/nature14066
复制
发表时间：
2015-04-09
期刊：
影响因子：
64.8
通讯作者：
Brody CD
中科院分区：
文献类型：
--
作者：
Hanks TD;Kopec CD;Brunton BW;Duan CA;Erlich JC;Brody CD
证据的逐渐积累被认为是决策的基础，其神经相关性已在多个大脑区域被发现。在这里，我们开发了一种可推广的方法来测量调谐曲线，指定神经反应和心理积累的证据之间的关系，并将其应用于区分后顶叶皮层（PPC）和前额叶皮层（额叶定向场，FOF）的决策变量的编码。我们记录了执行知觉决策任务的大鼠PPC和FOF神经元的放电率。经典分析揭示了积累证据的相关性，类似于先前在灵长类动物中的观察结果，在两个地区也相似。然而，调谐曲线分析显示，虽然PPC编码累积证据的分级值，但FOF具有更明确的编码，在整个试验过程中，该编码指示迄今为止累积的证据暂时支持的决定。与目前的观点相反，这表明额叶皮层的前运动活动在积累过程中并不起作用，而是具有更明确的功能，例如将积累的证据转化为离散的选择。为了因果地探索FOF活性的作用，我们在试验的不同时间点对光遗传学沉默它。与在证据积累过程结束时致力于分类选择的作用一致，但与积累过程本身的作用不一致，只有在感知刺激结束时发生FOF沉默时才观察到行为效应。我们的结果对参与决策的大脑区域的电路逻辑施加了重要的限制。
Gradual accumulation of evidence is thought to be fundamental for decision-making, and its neural correlates have been found in multiple brain regions. Here we develop a generalizable method to measure tuning curves that specify the relationship between neural responses and mentally-accumulated evidence, and apply it to distinguish the encoding of decision variables in posterior parietal cortex (PPC) and prefrontal cortex (frontal orienting fields, FOF). We recorded the firing rates of neurons in PPC and FOF from rats performing a perceptual decision-making task. Classical analyses uncovered correlates of accumulating evidence, similar to previous observations in primates and also similar across the two regions. However, tuning curve assays revealed that while the PPC encodes a graded value of the accumulating evidence, the FOF has a more categorical encoding that indicates, throughout the trial, the decision provisionally favored by the evidence accumulated so far. Contrary to current views, this suggests that premotor activity in frontal cortex does not play a role in the accumulation process, but instead has a more categorical function, such as transforming accumulated evidence into a discrete choice. To causally probe the role of FOF activity, we optogenetically silenced it during different timepoints of the trial. Consistent with a role in committing to a categorical choice at the end of the evidence accumulation process, but not consistent with a role during the accumulation itself, a behavioral effect was observed only when FOF silencing occurred at the end of the perceptual stimulus. Our results place important constraints on the circuit logic of brain regions involved in decision-making.