Temporal context in face perception: The interaction of competition and prediction

一个人的给定图片在不同的时间可能看起来不同。与其他人的先前遭遇，或者换句话说，给定面孔的时间背景会改变其感知。我们以前的研究启动和适应是形成理论的神经机制和表征涉及的面孔知觉。当我们开始理解这两种现象之间的关系时，对自上而下的过程（如预测、注意力提示和刺激之间的感官竞争）之间的相互作用的解释变得越来越重要。在这个项目建议中，我们将继续研究的影响，以前的经验对面孔知觉的心理物理学，电生理学和神经影像学方法预测编码模型的理论框架内。在我们计划的两个实验中，我们将使用重复的刺激，导致特定的，高水平的后效，启动或预测线索。在第一行中，我们将利用先前发现的多个同时呈现的面部之间的相互作用（Nagy等人，2011年）。首先，使用事件相关电位（ERP）记录，我们将测试的时间动态的感觉之间的竞争面孔。其次，我们将比较不同刺激类别与面孔相比的竞争效应（表现为血氧水平依赖（BOLD）信号的减少），并将测试先前的刺激，作为注意力线索是否能够使这些竞争对各种类别产生类似的偏见。作为这一实验路线的第三部分，我们将研究面部的竞争性相互作用如何被所谓的“身体-完形”效应所改变（Mielet et al，2011）。我们将测试面部和身体部位之间的竞争效应，并使用功能性磁共振成像（fMRI）来评估它们的神经编码如何在将整个人视为“完形”的过程中发生变化。在第二行（主要是fMRI）实验中，我们将集中于预测提示，注意力和适应性的相互作用。在我们的第一个实验中，我们将试图通过正交操纵两种效应，从被动刺激概率的影响中分离出预期的影响。第二，使用模糊的刺激（Cziraki et al.，2010）我们将测试预测是否影响神经元反应本身，或者仅仅是由于适应而导致的抑制。最后，我们将测试预测提示如何影响面孔和其他刺激类别之间的感官竞争。

A given picture of a person might look different at different times. Previous encounters with other people or in other words, the temporal context of a given face modifies its perception. Our previous research on priming and adaptation is shaping theories about the neural mechanisms and representations involved in face perception. As we are beginning to understand the relationship between these two phenomena, an account of the interaction between top-down processes, such as predictions, attentional cueing and sensory competition among stimuli becomes increasingly important. In this project proposal, we will continue to study the effect of previous experiences on face perception using psychophysical, electrophysiological and neuroimaging methods within the theoretical frame of predictive coding models. In two lines of our planned experiments we will use repeated stimuli, leading to specific, high-level aftereffects, priming or predictive cueing. In the first line we will capitalize upon the previously found interactions among multiple simultaneously presented faces (Nagy et al., 2011). First, using event-related potential (ERP) recordings we will test the temporal dynamics of sensory competition among faces. Second, we will compare the competition effect (manifested in the reduction of blood oxygen level dependent (BOLD) signal) for different stimulus categories compared to faces and will test if a prior stimulus, serving as an attentional cue is able to bias these competitions similarly for various categories or not. As a third part of this experimental line we will study how the competitive interactions of faces are modified by the so-called “body-Gestalt” effect (Miellet et al, 2011). We will test competition effects among faces and body-parts and use functional magnetic resonance imaging (fMRI) to evaluate how their neural coding changes during the perception of an entire person as a “Gestalt”.In the second line of (mostly fMRI) experiments we will concentrate on the interaction of predictive cueing, attention and adaptation. In our first experiments, we will try to disentangle the effect of expectation from that of passive stimulus probability by manipulating both effects orthogonally. Second, using ambiguous stimuli (Cziraki et al., 2010) we will test whether prediction affects the neuronal responses per se or rather only their suppression, due to adaptation. Finally, we will test how predictive cueing affects sensory competition among faces and other stimulus categories.