School of Psychology, Social Work and Social Policy, University of South Australia, Australia; Melbourne School of Psychological Sciences, The University of Melbourne, Australia.
School of Psychology, Social Work and Social Policy, University of South Australia, Australia.
Neuropsychologia. 2019 Jan;122:76-87. doi: 10.1016/j.neuropsychologia.2018.11.010. Epub 2018 Nov 22.
Repeated exposure to a stimulus leads to reduced responses of stimulus-selective sensory neurons, an effect known as repetition suppression or stimulus-specific adaptation. Several influential models have been proposed to explain repetition suppression within hierarchically-organised sensory systems, with each specifying different mechanisms underlying repetition effects. We manipulated temporal expectations within a face repetition experiment to test a critical prediction of the predictive coding model of repetition suppression: that repetition effects will be larger following stimuli that appear at expected times compared to stimuli that appear at unexpected times. We recorded event-related potentials from 18 participants and mapped the spatiotemporal progression of repetition effects using mass univariate analyses. We then assessed whether the magnitudes of observed face image repetition effects were influenced by temporal expectations. In each trial participants saw an adapter face, followed by a 500 ms or 1000 ms interstimulus interval (ISI), and then a test face, which was the same or a different face identity to the adapter. Participants' expectations for whether the test face would appear after a 500 ms ISI were cued by the sex of the adapter face. Our analyses revealed multiple repetition effects with distinct scalp topographies, extending until at least 800 ms from stimulus onset. An early (158-203 ms) repetition effect was larger for stimuli following surprising, rather than expected, 500 ms ISI durations, contrary to the model predictions of the predictive coding model of repetition suppression. During this time window temporal expectation effects were larger for alternating, compared to repeated, test stimuli. Statistically significant temporal expectation by stimulus repetition interactions were not found for later (230-609 ms) time windows. Our results provide further evidence that repetition suppression can reduce neural effects of expectation and surprise, indicating that there are multiple interactive mechanisms supporting sensory predictions within the visual hierarchy.
重复刺激会导致对刺激选择性感觉神经元的反应减少，这种效应被称为重复抑制或刺激特异性适应。已经提出了几种有影响力的模型来解释层次组织感觉系统中的重复抑制，每个模型都指定了重复效应背后的不同机制。我们在面部重复实验中操纵了时间预期，以检验重复抑制的预测编码模型的一个关键预测：与出现在意外时间的刺激相比，出现在预期时间的刺激会产生更大的重复效应。我们从 18 名参与者那里记录了事件相关电位，并使用大规模单变量分析绘制了重复效应的时空进展图。然后，我们评估了观察到的面孔图像重复效应的幅度是否受到时间预期的影响。在每个试验中，参与者首先看到一个适配器面孔，然后是 500 毫秒或 1000 毫秒的刺激间间隔（ISI），然后是一个测试面孔，该测试面孔与适配器面孔的身份相同或不同。参与者对测试面孔在 500 毫秒 ISI 后出现的预期通过适配器面孔的性别进行提示。我们的分析揭示了具有不同头皮拓扑的多个重复效应，这些效应一直延伸到刺激开始后至少 800 毫秒。对于出现在令人惊讶而不是预期的 500 毫秒 ISI 持续时间之后的刺激，早期（158-203 毫秒）重复效应更大，与重复抑制的预测编码模型的模型预测相反。在这个时间窗口中，与重复测试刺激相比，交替测试刺激的时间预期效应更大。对于较晚的（230-609 毫秒）时间窗口，没有发现时间预期与刺激重复相互作用的统计学显著差异。我们的结果提供了进一步的证据，表明重复抑制可以减少期望和惊讶的神经效应，表明在视觉层次结构中存在多种支持感觉预测的相互作用机制。
