Multisensory integration, sensory recalibration, and the reduction of cross-modal perceptual discrepancies

我们通过组合不同感官的信息来体验环境。通常，这些至少提供了一些不一致的证据，我们的大脑面临着将这些信息合并成一个连贯和统一的感知的挑战。例如，当视觉和听觉刺激出现在不同的位置，或者当手的运动结束在与视觉感知的位置不同的位置时，空间偏见会影响我们的知觉。也就是说，事件的感知位置偏离了物理现实，或者偏离了如果只有一个刺激存在时所感知的。这种跨模式偏差可能源于任何给定时刻可获得的不一致的多感觉信息，这一过程被称为多感觉整合。然而，这种偏见也可能源于对持续数分钟或更长时间的多感官环境的差异的适应，这一过程被称为重新校准。虽然在典型的实验环境中，整合和重新校准在不同的时间尺度上出现，但它们都是减少可用感觉信息中明显差异的中心机制。我们在这里建议研究多感觉整合和重新校准的知觉机制，以及这些机制如何相互作用共同塑造知觉。我们侧重于两种范式：一种依赖于被动的视听知觉，另一种是利用视觉反馈下的手部运动与环境的主动交互(视觉-运动任务)，以区分概括跨通道的结果和知觉任务的性质与特定范式的结果。我们关注从以前的工作中得出的三个关键假设，每个假设都将在单独的一系列实验中进行测试：i)这两个过程同时受到观察者的信念的调制，即表面上不同的信息实际上来自一个共同的对象；ii)两个过程同时受到两个通道的相对可靠性的影响；iii)整合和重新校准都是为了确保一致的感知，但每一个都是通过消除不同时间尺度上的感觉差异来实现的。了解引导多感觉整合和再校准之间相互作用的机制，对于理解大脑如何灵活地适应现实生活环境中往往不稳定的感觉证据至关重要。反过来，这种理解可以用来揭示大脑中潜在的神经机制，以及感知挑战如何影响患有感觉障碍、特定障碍或认知衰退的个人。

We experience the environment by combining information across our different senses. Often, these provide at least somewhat discrepant evidence, and our brain is faced with the challenge to merge this information into a coherent and unified percept. For example, when visual and auditory stimuli are presented at different locations, or when a hand movement ends at a location different from the one perceived visually, spatial biases influence our percepts. That is, the perceived location of an event deviates from the physical reality, or from what would be perceived if only a single stimulus had been present. Such cross-modal biases can arise from the discrepant multisensory information available at any given moment, a process known as multisensory integration. However, such biases can also arise from the adaptation to discrepancies in the multisensory environment that persist for minutes or longer, a process known as recalibration. While in typical experimental settings integration and recalibration emerge on distinct time scales, they are both central mechanisms to reduce apparent discrepancies in the available sensory information. We here propose to investigate the perceptual mechanisms underlying multisensory integration and recalibration, and how these interact to collectively shape perception. We focus on two paradigms: one relying on passive audio-visual perception, the other capitalizing the active interaction with the environment via hand movements under visual feedback (visuo-motor task), in order to distinguish results that generalize across modalities and the nature of the perceptual task from paradigm-specific results. We focus on three key hypotheses derived from previous work, each to be tested in a separate series of experiments: i) both processes are modulated in parallel by the observer’s belief that the apparently discrepant information actually arises from a common object; ii) both processes are affected in parallel by the relative reliabilities of the two modalities; and iii) integration and recalibration both work to ensure a coherent percept, but each by removing sensory discrepancies on distinct time scales. Knowledge of mechanisms that guide the interplay between multisensory integration and recalibration is paramount to understand how the brain flexibly adapts to the often volatile sensory evidence in real-life environments. In turn, this understanding can then be used to uncover the underlying neural mechanisms in the brain, and how perceptual challenges affect individuals with sensory disabilities, specific disorders, or during cognitive decline.