Chan Jason S, Wibral Michael, Stawowsky Cerisa, Brandl Mareike, Helbling Saskia, Naumer Marcus J, Kaiser Jochen, Wollstadt Patricia
Institute of Medical Psychology, Goethe-University, Frankfurt, Germany.
School of Applied Psychology, University College Cork, Cork, Ireland.
Front Aging Neurosci. 2021 Apr 9;13:631599. doi: 10.3389/fnagi.2021.631599. eCollection 2021.
Aging is accompanied by unisensory decline. To compensate for this, two complementary strategies are potentially relied upon increasingly: first, older adults integrate more information from different sensory organs. Second, according to the predictive coding (PC) model, we form "templates" (internal models or "priors") of the environment through our experiences. It is through increased life experience that older adults may rely more on these templates compared to younger adults. Multisensory integration and predictive coding would be effective strategies for the perception of near-threshold stimuli, which may however come at the cost of integrating irrelevant information. Both strategies can be studied in multisensory illusions because these require the integration of different sensory information, as well as an internal model of the world that can take precedence over sensory input. Here, we elicited a classic multisensory illusion, the sound-induced flash illusion, in younger (mean: 27 years, N = 25) and older (mean: 67 years, N = 28) adult participants while recording the magnetoencephalogram. Older adults perceived more illusions than younger adults. Older adults had increased pre-stimulus beta-band activity compared to younger adults as predicted by microcircuit theories of predictive coding, which suggest priors and predictions are linked to beta-band activity. Transfer entropy analysis and dynamic causal modeling of pre-stimulus magnetoencephalography data revealed a stronger illusion-related modulation of cross-modal connectivity from auditory to visual cortices in older compared to younger adults. We interpret this as the neural correlate of increased reliance on a cross-modal predictive template in older adults leading to the illusory percept.
衰老伴随着单感官衰退。为了弥补这一点，可能越来越多地依赖两种互补策略：第一，老年人整合来自不同感觉器官的更多信息。第二，根据预测编码（PC）模型，我们通过经验形成环境的“模板”（内部模型或“先验”）。与年轻人相比，老年人可能更多地依赖这些模板，这是通过增加生活经验实现的。多感官整合和预测编码对于接近阈值刺激的感知将是有效的策略，然而这可能会以整合无关信息为代价。这两种策略都可以在多感官错觉中进行研究，因为这些错觉需要整合不同的感官信息，以及一个可以优先于感官输入的世界内部模型。在这里，我们在记录脑磁图的同时，在年轻（平均年龄：27岁，N = 25）和年长（平均年龄：67岁，N = 28）成年参与者中诱发了一种经典的多感官错觉，即声音诱发闪光错觉。年长成年人比年轻成年人感知到更多的错觉。与预测编码的微电路理论所预测的一样，与年轻成年人相比，年长成年人在刺激前的β波段活动增加，这表明先验和预测与β波段活动有关。对刺激前脑磁图数据的转移熵分析和动态因果建模显示，与年轻成年人相比，年长成年人中从听觉皮层到视觉皮层的跨模态连接的错觉相关调制更强。我们将此解释为年长成年人对跨模态预测模板的依赖增加导致错觉感知的神经关联。
