Neuroscience Institute, New York University Medical Center, 435 East 30(th) Street, New York 10016, USA; Department of Psychological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK.
Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK.
Curr Biol. 2024 May 20;34(10):2265-2271.e4. doi: 10.1016/j.cub.2024.04.036. Epub 2024 May 1.
Popular accounts of mind and brain propose that the brain continuously forms predictions about future sensory inputs and combines predictions with inputs to determine what we perceive. Under "predictive processing" schemes, such integration is supported by the hierarchical organization of the cortex, whereby feedback connections communicate predictions from higher-level deep layers to agranular (superficial and deep) lower-level layers. Predictions are compared with input to compute the "prediction error," which is transmitted up the hierarchy from superficial layers of lower cortical regions to the middle layers of higher areas, to update higher-level predictions until errors are reconciled. In the primary visual cortex (V1), predictions have thereby been proposed to influence representations in deep layers while error signals may be computed in superficial layers. Despite the framework's popularity, there is little evidence for these functional distinctions because, to our knowledge, unexpected sensory events have not previously been presented in human laminar paradigms to contrast against expected events. To this end, this 7T fMRI study contrasted V1 responses to expected (75% likely) and unexpected (25%) Gabor orientations. Multivariate decoding analyses revealed an interaction between expectation and layer, such that expected events could be decoded with comparable accuracy across layers, while unexpected events could only be decoded in superficial laminae. Although these results are in line with these accounts that have been popular for decades, such distinctions have not previously been demonstrated in humans. We discuss how both prediction and error processes may operate together to shape our unitary perceptual experiences.
流行的心智和大脑理论认为，大脑不断对未来的感官输入形成预测，并将预测与输入结合起来，以确定我们所感知的内容。在“预测加工”理论中，这种整合是由皮质的层次组织支持的，其中反馈连接将来自高层深层的预测传递到无颗粒（浅层和深层）的较低层。预测与输入进行比较，以计算“预测误差”，该误差从较低皮质区域的浅层向上传递到较高区域的中层，以更新高层预测，直到误差得到协调。在初级视觉皮层 (V1) 中，已经提出预测会影响深层的表示，而错误信号可能在浅层中计算。尽管该框架很流行，但由于我们所知，以前在人类层状范式中没有呈现意外的感官事件来与预期事件形成对比，因此几乎没有证据支持这些功能区分。为此，这项 7T fMRI 研究对比了 V1 对预期（75%的可能性）和意外（25%）的 Gabor 方向的反应。多元解码分析显示，期望和层之间存在相互作用，使得可以在所有层中以相当的精度解码预期事件，而只能在浅层中解码意外事件。尽管这些结果与几十年来一直流行的这些解释一致，但以前在人类中没有证明过这些区别。我们讨论了预测和误差过程如何共同作用，以塑造我们单一的感知体验。
