Radboud University, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
Sci Rep. 2018 Aug 3;8(1):11644. doi: 10.1038/s41598-018-30221-2.
Decoding has become a standard analysis technique for contemporary cognitive neuroscience. Already more than a decade ago, it was shown that orientation information could be decoded from functional magnetic resonance imaging voxel time series. However, the underlying neural mechanism driving the decodable information is still under debate. Here, we investigated whether eye movements and pupil dilation during attempted fixation and passive viewing of visually presented square-wave grating stimuli could explain orientation decoding. We hypothesized that there are confounding orientation-dependent fixational eye movements (e.g., microsaccades), which systematically alter brain activity, and hence can be the source of decodable information. We repeated one of the original orientation decoding studies, but recorded eye movements instead of brain activity. We found no evidence that stimulus orientation can be decoded from eye movements under baseline conditions, but cannot rule out the potential confounding effect of eye movements under different conditions. With this study, we emphasize the importance, and show the implications of such potential confounding eye movements for decoding studies and cognitive neuroscience in general.
解码已经成为当代认知神经科学的标准分析技术。早在十多年前，就已经证明可以从功能磁共振成像体素时间序列中解码方向信息。然而，驱动可解码信息的潜在神经机制仍存在争议。在这里，我们研究了在尝试注视和被动观看视觉呈现的方波光栅刺激时的眼动和瞳孔扩张是否可以解释方向解码。我们假设存在与方向相关的混淆性注视眼动（例如微扫视），这些眼动会系统地改变大脑活动，因此可能是可解码信息的来源。我们重复了其中一个原始的方向解码研究，但记录了眼动而不是大脑活动。我们没有发现证据表明可以从基线条件下的眼动中解码出刺激方向，但不能排除在不同条件下眼动的潜在混杂效应。通过这项研究，我们强调了这种潜在混杂眼动对解码研究和一般认知神经科学的重要性，并展示了其影响。
