Cortical mechanisms of temporal perception

我们的感官不断地从周围环境中接收到多种信息。然而，我们的感官能力是有限的。例如，时间分辨率是有限的，因此，如果刺激之间的时间差异低于某个阈值，则无法解决。视觉系统的局限性可以在电影中看到。虽然一部电影是由一系列静态帧组成的，但视觉系统的时间分辨率不足以分辨单个帧。关于限制时间感知的神经元过程一直存在争论。一个争论了几十年的理论认为，时间感知是由所谓的感知周期介导的。在该理论中，感知周期是时间整合窗口，因此在一个感知周期内接收到的任何信息将被整合到一个单一的时间感知中。知觉循环因此建立了知觉的核心单元。最近的研究为这一理论提供了新的证据。这些研究将感知周期与特定频率的神经元振荡周期联系起来。因此，神经元振荡可能代表了感知周期的神经元基础。虽然这一理论看起来很有趣，但大多数证据都是相关的，而因果证据在很大程度上缺失。在这个项目中，我的目标是调查和建立神经元振荡和时间感知之间的因果关系。使用脑磁图（MEG），当健康参与者执行时间辨别任务时，神经元振荡将被测量。通过药物干预，神经振荡将被调节。具体来说，GBAergic中间神经元，已知在神经元振荡的产生中起着至关重要的作用，将通过药物干预来调节。同时，这种调制对时间感知的影响将被测量。通过这种定向调制，可以研究神经元振荡和时间感知之间的假定因果关系。此外，在这个项目中，有可能弥合神经化学活动、中观水平上的神经元振荡活动以及行为水平上的感知之间的差距。

Our senses constantly receive multiple bits of information from our surrounding environment. The capacity of our senses, however, is limited. For example, the temporal resolution is limited so that temporal differences between stimuli cannot be resolved if the differences are below a certain threshold. The limitation of the visual system can be seen for example in movies. Although a movie consists of a series of static frames, the temporal resolution of the visual system is not high enough to resolve the single frames.There is an ongoing debate about the neuronal processes that limit temporal perception. One theory debated for decades states that temporal perception is mediated by so-called perceptual cycles. In this theory, perceptual cycles are temporal integration windows, such that any information received within one perceptual cycle will be integrated to one single temporal percept. Perceptual cycles thus build a core unit of perception.Recent studies provided new evidence for this theory. These studies linked perceptual cycles to cycles of neuronal oscillations of a specific frequency. Consequently, neuronal oscillations might represent the neuronal basis of perceptual cycles. Although this theory seems intriguing, most evidence for the theory is only of correlative nature, while causal evidence is largely missing.In this project, I aim to investigate and establish a causal link between neuronal oscillations and temporal perception. Using magnetoencephalography (MEG), neuronal oscillations will be measured while the healthy participants perform a temporal discrimination task. By means of pharmacological intervention, neuronal oscillations will be modulated. Specifically, GBAergic interneurons, which are known to play a crucial role in the generation of neuronal oscillations, will be modulated by pharmacological intervention. Simultaneously, the impact of this modulation on temporal perception will be measured. By this directed modulation, the putative causal link between neuronal oscillations and temporal perception can be studied. Furthermore, in this project it might be possible to bridge a gap between neurochemical activity, neuronal oscillatory activity on a mesoscopic level as well as perception on the behavioural level.