The role of conditioning in perceptual inference

我们大脑所能获得的感官数据基本上是贫乏的信息来源。然而，我们对世界的感知通常是丰富的、统一的和连贯的。为了产生这种可以作为行为可靠指南的连贯感知，我们的大脑需要推断出感觉数据背后的原因。因此，感知通常被定义为一种积极的推理过程，它使用内源性预测来“理解”可用的感官数据。知觉推断是自适应的，因为这些预测不断被新的感官证据更新。似乎很明显，这种适应过程应该由其后果来决定，也就是说，一个感知是否与有利或厌恶的事件有关。然而，令人惊讶的是，人们对这种条件作用在知觉推理中的作用知之甚少。当前提议的关键假设是，感知推理是一个主动的过程，以类似于行为的方式由条件作用调节。除了这种操作性条件反射（这里称为知觉条件反射）之外，还假设一种形式的经典条件反射（这里称为刺激条件反射）也可能在知觉推断中发挥作用。本项目旨在通过一系列行为和功能磁共振成像（fMRI）实验，利用知觉模糊范式阐明知觉和刺激条件反射在知觉推理中的作用。知觉与刺激条件反射的机制将通过将知觉选择与金钱输赢联系起来来解开，就像在操作性条件反射中一样；或者通过将争夺意识的视觉刺激与金钱的输赢联系起来，就像经典条件反射一样。至关重要的是，在观看模糊刺激时发生的主观知觉变化将用客观措施进行评估，以排除主观报告的潜在混淆效应。在行为上，感知将通过探针检测任务间接跟踪。为了在神经水平上提供感知的客观测量，将使用功能磁共振成像数据的多变量模式分析来解码感知特异性脑信号的感知。此外，知觉推理中条件反射的神经基础将通过单变量统计方法结合有效连接模型进行研究。预期本研究将在行为和神经水平上为知觉和刺激条件作用的分离效应提供证据。因此，拟议的项目将通过揭示迄今为止尚未探索的感知推理方面，进一步加深我们对意识感知机制的理解。它还将为未来研究情感障碍和精神分裂症等精神疾病中知觉体验改变的潜在机制铺平道路。

The sensory data available to our brains are a fundamentally impoverished source of information. However, we nonetheless usually experience our perception of the world as rich, unitary and coherent. To generate such coherent perception that can be used as a reliable guide to behaviour, our brains need to infer the causes underlying the sensory data. Perception is therefore commonly conceptualized as an active inferential process that uses endogenous predictions to 'make sense' of the available sensory data. Perceptual inference is adaptive in that these predictions are constantly updated by new sensory evidence. It seems obvious that such an adaptive process should be shaped by its consequences, that is, whether a percept is associated with favourable or aversive events. Surprisingly, however, little is known about the role of such conditioning in perceptual inference. The key assumption of the current proposal is that perceptual inference is an active process that is modulated by conditioning in a similar way as behaviour. In addition to such operant-like conditioning, which is here referred to as percept conditioning, it is also assumed that a form of classical conditioning (here: stimulus conditioning) may also play a role in perceptual inference. This project aims to elucidate the roles of percept and stimulus conditioning in perceptual inference using the paradigm of perceptual ambiguity in a series of behavioural and functional magnetic resonance imaging (fMRI) experiments. The mechanisms of percept vs. stimulus conditioning will be disentangled by either associating perceptual choices with monetary wins or losses, just as in operant conditioning; or by associating visual stimuli that compete for awareness with monetary wins or losses, as in classical conditioning. Crucially, subjective perceptual alternations that occur during the viewing of ambiguous stimuli will be assessed with objective measures in order to preclude potential confounding effects of subjective reports. Behaviourally, perception will be tracked indirectly with a probe detection task. To provide an objective measure of perception at the neural level, multivariate pattern analysis of fMRI data will be used to decode perception from percept-specific brain signals. Moreover, the neural basis of conditioning in perceptual inference will be investigated with a univariate statistical approach in conjunction with models of effective connectivity. It is expected that this research will provide evidence for dissociable effects of percept and stimulus conditioning both at the behavioural and the neural level. The proposed project will thus further our understanding of the mechanisms underlying conscious perception by shedding light on a hitherto largely unexplored aspect of perceptual inference. It will also pave the way for future research into the mechanisms underlying altered perceptual experience in psychiatric diseases such as affective disorders and schizophrenia.