Data from: Testing sensory evidence against mnemonic templates

Most perceptual decisions require comparisons between current input and an
internal template. Classic studies propose that templates are encoded in
sustained activity of sensory neurons. However, stimulus encoding is
itself dynamic, tracing a complex trajectory through activity space. Which
part of this trajectory is pre-activated to reflect the template? Here we
recorded magneto- and electroencephalography during a visual
target-detection task, and used pattern analyses to decode template,
stimulus, and decision-variable representation. Our findings ran counter
to the dominant model of sustained pre-activation. Instead, template
information emerged transiently around stimulus onset and quickly
subsided. Cross-generalization between stimulus and template coding,
indicating a shared neural representation, occurred only briefly. Our
results are compatible with the proposal that template representation
relies on a matched filter, transforming input into task-appropriate
output. This proposal was consistent with a signed difference response at
the perceptual decision stage, which can be explained by a simple neural
model.

多数知觉决策需要将当前输入与内部模板进行比较。经典研究认为，模板编码于感觉神经元的持续活动中。然而，刺激编码本身具有动态性，其在活动空间中沿复杂轨迹演化。该轨迹的哪一部分会被预激活以反映模板？本研究在视觉目标检测任务中记录了脑磁图（magnetoencephalography, MEG）与脑电图（electroencephalography, EEG），并通过模式分析解码模板、刺激及决策变量的表征。我们的发现与持续预激活的主导模型相悖。相反，模板信息在刺激出现前后短暂浮现并迅速消退。刺激与模板编码间的交叉泛化（提示存在共享神经表征）仅短暂发生。我们的结果与"模板表征依赖匹配滤波器（matched filter），将输入转换为任务适配输出"的假说一致。该假说与知觉决策阶段的符号差异响应（signed difference response）相符，且可通过简单神经模型解释。