Cuturi Luigi F, MacNeilage Paul R
German Center for Vertigo, University Hospital of Munich, 81377 Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians University, 82152 Planegg-Martinsried, Germany.
German Center for Vertigo, University Hospital of Munich, 81377 Munich, Germany.
Curr Biol. 2014 Dec 1;24(23):2817-21. doi: 10.1016/j.cub.2014.10.015. Epub 2014 Nov 20.
There is strong evidence of shared neurophysiological substrates for visual and vestibular processing that likely support our capacity for estimating our own movement through the environment. We examined behavioral consequences of these shared substrates in the form of crossmodal aftereffects. In particular, we examined whether sustained exposure to a visual self-motion stimulus (i.e., optic flow) induces a subsequent bias in nonvisual (i.e., vestibular) self-motion perception in the opposite direction in darkness. Although several previous studies have investigated self-motion aftereffects, none have demonstrated crossmodal transfer, which is the strongest proof that the adapted mechanisms are generalized for self-motion processing. The crossmodal aftereffect was quantified using a motion-nulling procedure in which observers were physically translated on a motion platform to find the movement required to cancel the visually induced aftereffect. Crossmodal transfer was elicited only with the longest-duration visual adaptor (15 s), suggesting that transfer requires sustained vection (i.e., visually induced self-motion perception). Visual-only aftereffects were also measured, but the magnitudes of visual-only and crossmodal aftereffects were not correlated, indicating distinct underlying mechanisms. We propose that crossmodal aftereffects can be understood as an example of contingent or contextual adaptation that arises in response to correlations across signals and functions to reduce these correlations in order to increase coding efficiency. According to this view, crossmodal aftereffects in general (e.g., visual-auditory or visual-tactile) can be explained as accidental manifestations of mechanisms that constantly function to calibrate sensory modalities with each other as well as with the environment.
有强有力的证据表明，视觉和前庭处理存在共同的神经生理基质，这可能支持我们在环境中估计自身运动的能力。我们以跨通道后效应的形式研究了这些共同基质的行为后果。具体而言，我们研究了持续暴露于视觉自我运动刺激（即视觉流）是否会在黑暗中导致非视觉（即前庭）自我运动感知随后出现相反方向的偏差。尽管之前有几项研究调查了自我运动后效应，但没有一项研究证明了跨通道转移，而跨通道转移是适应机制可推广用于自我运动处理的最有力证据。使用运动抵消程序对跨通道后效应进行量化，在该程序中，观察者在运动平台上进行实际平移，以找到抵消视觉诱发后效应所需的运动。仅在最长持续时间的视觉适应刺激（15秒）下才引发了跨通道转移，这表明转移需要持续的视动感受（即视觉诱发的自我运动感知）。我们还测量了仅视觉的后效应，但仅视觉后效应和跨通道后效应的大小不相关，这表明它们有不同的潜在机制。我们提出，跨通道后效应可以理解为一种偶然或情境适应的例子，它是为了响应信号和功能之间的相关性而产生的，以减少这些相关性，从而提高编码效率。根据这一观点，一般的跨通道后效应（如视觉-听觉或视觉-触觉）可以解释为不断校准感官模式以及与环境的机制的偶然表现。
