Serin Fatih, Wang Danying, Davis Matthew H, Henson Richard
MRC Cognition and Brain Sciences Unit, University of Cambridge, UK.
Centre for Cognitive Neuroimaging, School of Psychology & Neuroscience, University of Glasgow, UK.
Brain Neurosci Adv. 2024 May 24;8:23982128241255798. doi: 10.1177/23982128241255798. eCollection 2024 Jan-Dec.
The binding of information from different sensory or neural sources is critical for associative memory. Previous research in animals suggested that the timing of theta oscillations in the hippocampus is critical for long-term potentiation, which underlies associative and episodic memory. Studies with human participants showed correlations between theta oscillations in medial temporal lobe and episodic memory. Clouter et al. directly investigated this link by modulating the intensity of the luminance and the sound of the video clips so that they 'flickered' at certain frequencies and with varying synchronicity between the visual and auditory streams. Across several experiments, better memory was found for stimuli that flickered synchronously at theta frequency compared with no-flicker, asynchronous theta, or synchronous alpha and delta frequencies. This effect - which they called the theta-induced memory effect - is consistent with the importance of theta synchronicity for long-term potentiation. In addition, electroencephalography data showed entrainment of cortical regions to the visual and auditory flicker, and that synchronicity was achieved in neuronal oscillations (with a fixed delay between visual and auditory streams). The theoretical importance, large effect size, and potential application to enhance real-world memory mean that a replication of theta-induced memory effect would be highly valuable. The present study aimed to replicate the key differences among synchronous theta, asynchronous theta, synchronous delta, and no-flicker conditions, but within a single experiment. The results do not show evidence of improved memory for theta synchronicity in any of the comparisons. We suggest a reinterpretation of theta-induced memory effect to accommodate this non-replication.
整合来自不同感官或神经源的信息对于关联记忆至关重要。先前对动物的研究表明，海马体中θ振荡的时间对于长时程增强至关重要，而长时程增强是关联记忆和情景记忆的基础。对人类参与者的研究表明，内侧颞叶中的θ振荡与情景记忆之间存在相关性。克劳特等人通过调节视频片段的亮度和声音强度，使其以特定频率“闪烁”，且视觉和听觉流之间具有不同的同步性，从而直接研究了这种联系。在多个实验中，与无闪烁、异步θ或同步α和δ频率相比，发现以θ频率同步闪烁的刺激的记忆效果更好。他们将这种效应——称为θ诱导记忆效应——与θ同步性对长时程增强的重要性相一致。此外，脑电图数据显示皮质区域与视觉和听觉闪烁同步，并且在神经元振荡中实现了同步性（视觉和听觉流之间有固定延迟）。其理论重要性、大效应量以及在增强现实世界记忆方面的潜在应用意味着对θ诱导记忆效应的重复研究将具有很高的价值。本研究旨在在单个实验中重复同步θ、异步θ、同步δ和无闪烁条件之间的关键差异。但结果并未显示在任何比较中存在θ同步性导致记忆改善的证据。我们建议对θ诱导记忆效应进行重新解释以适应这一未重复的结果。
