Prediction in Visual Cortex

描述(申请人提供)：大脑最基本和最普遍的功能之一是检测意外事件的发生，因此可能会提供信息。这一功能建立在两个基础之上。首先，大脑必须从正在进行的经验中提取关于环境的过渡性统计数据的信息：关于哪些事件往往紧随哪些其他事件的信息。第二，它必须监测正在进行的经验，以便在违反基于先前经验的过渡统计数据的预测时发出信号。我们知道大脑完成了这些壮举，但我们对潜在的神经机制知之甚少。我们建议通过研究最近在灵长类视觉系统中发现的一种现象来研究这个问题：预测抑制。预测抑制是通过允许猴子重复观看图像以固定顺序紧随其后的显示来诱导的。在随后的观看中，TE区(颞叶的一个视觉区域)中的神经元对训练序列中的图像反应较弱，但对看起来无序的图像反应强烈。这一现象有可能成为研究大脑中调节预测过程的神经机制的试验台。拟议项目的总体目标是回答有关预测抑制的基本悬而未决的问题，以巩固该现象作为研究预测过程的神经机制的模型的地位。我们提出了三组实验。在所有这些实验中，我们将在训练期间让猴子观看由固定过渡统计数据控制的动态显示，然后在测试期间监测神经元对预测和未预测序列的反应。第一系列中的实验将描述诱导预测抑制所需的条件。第二个系列中的实验将描述通过呈现预测性刺激而启动的神经过程。第三个系列的实验将确定预测抑制在区域TE水平之前和之后的视觉处理阶段是否明显。

DESCRIPTION (provided by applicant): One of the most basic and general functions of the brain is to detect the occurrence of unexpected and therefore potentially informative events. This function rests on two foundations. First, the brain must extract from ongoing experience information about the transitional statistics of the environment: information about what events tend to follow what other events. Second, it must monitor ongoing experience so as to signal when predictions based on previously experienced transitional statistics are violated. We know that the brain accomplishes these feats but we know little about the underlying neuronal mechanisms. We propose to investigate this problem by studying a phenomenon recently discovered in the primate visual system: prediction suppression. Prediction suppression is induced by allowing a monkey to view repeatedly a display in which images follow each other in fixed sequence. During subsequent viewing, neurons in area TE, a visual area in the temporal lobe, respond weakly to images in the trained sequence but respond strongly to images that appear out of sequence. This phenomenon possesses potential as a test bed for the study of neural mechanisms mediating predictive processes in the brain. The general goal of the proposed project is to answer fundamental outstanding questions about prediction suppression so as to solidify the status of the phenomenon as a model for studying the neural mechanisms of predictive processes. We propose three sets of experiments. In all of them, we will expose monkeys, during a training period, to dynamic displays governed by fixed transitional statistics and then, during a testing period, will monitor neuronal responses to predicted and unpredicted sequences. Experiments in the first series will characterize the conditions required for inducing prediction suppression. Experiments in the second series will characterize the neural processes initiated by presenting a predictive stimulus. Experiments in the third series will determine whether prediction suppression is manifest at visual processing stages before and after the level of area TE.