Furl Nicholas, van Rijsbergen Nicola J, Treves Alessandro, Friston Karl J, Dolan Raymond J
Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, United Kingdom.
Proc Natl Acad Sci U S A. 2007 Aug 14;104(33):13485-9. doi: 10.1073/pnas.0702548104. Epub 2007 Aug 7.
Sensory information from the external world is inherently ambiguous, necessitating prior experience as a constraint on perception. Prolonged experience (adaptation) induces perception of ambiguous morph faces as a category different from the adapted category, suggesting sensitivity in underlying neural codes to differences between input and recent experience. Using magnetoencephalography, we investigated the neural dynamics of such experience-dependent visual coding by focusing on the timing of responses to morphs after facial expression adaptation. We show that evoked fields arising from the superior temporal sulcus (STS) reflect the degree to which a morph and adapted expression deviate. Furthermore, adaptation effects within STS predict the magnitude of behavioral aftereffects. These findings show that the STS codes expressions relative to recent experience rather than absolutely and may bias perception of expressions. One potential neural mechanism for the late timing of both effects appeals to hierarchical models that ascribe a central role to backward connections in mediating predictive codes.
来自外部世界的感官信息本质上是模糊的，这就需要先前的经验作为感知的一种约束。长期的经验（适应）会导致对模糊形态面孔的感知成为与适应类别不同的类别，这表明潜在神经编码对输入与近期经验之间的差异具有敏感性。我们使用脑磁图，通过关注面部表情适应后对形态的反应时间，来研究这种依赖经验的视觉编码的神经动力学。我们发现，颞上沟（STS）产生的诱发场反映了形态与适应表情之间的偏离程度。此外，STS内的适应效应可预测行为后效的大小。这些发现表明，STS编码的是相对于近期经验而非绝对的表情，并且可能会影响对面部表情的感知。这两种效应延迟出现的一种潜在神经机制涉及层次模型，该模型认为反向连接在介导预测编码中起着核心作用。
