Wynn Syanah C, Townsend Christopher D, Nyhus Erika
Neuroimaging Center, Johannes Gutenberg University Medical Center Mainz, Mainz, Germany.
Department of Psychology and Program in Neuroscience, Bowdoin College, Brunswick, ME, United States.
bioRxiv. 2023 Oct 19:2023.10.18.562880. doi: 10.1101/2023.10.18.562880.
Theta and gamma oscillations have been linked to episodic memory processes in various studies. Both oscillations seem to be vital for processes guided by the medial temporal lobe, such as the retrieval of information from memory. While theta oscillations increase with successful memory, it is unclear what the unique contribution of theta is to various subcomponents of memory. On the other hand, memory-related gamma oscillations have been mainly reported in the hippocampus, leaving the role of neocortical gamma in memory underexplored. In the current study, we explored how unique variability in memory accuracy and memory confidence contributes to fluctuations in theta and gamma power. To this end, we recorded EEG from 54 participants while they performed a source memory task. From this task we obtained their item memory accuracy, source memory accuracy, item memory confidence, and source memory confidence. These behavioral measures were put in a trial-by-trial linear mixed effects model to uncover their unique contribution to the oscillatory power in frontal and parietal regions. Our results are in line with the involvement of theta oscillations in both memory accuracy and confidence, but seem to indicate a main role for theta oscillations in memory-related confidence. In addition, we found that gamma oscillations play various roles in memory-processing, dependent of brain region.
在各项研究中，θ波和γ波振荡已与情景记忆过程相关联。这两种振荡似乎对由内侧颞叶引导的过程至关重要，比如从记忆中检索信息。虽然成功记忆时θ波振荡会增强，但θ波对记忆各个子成分的独特贡献尚不清楚。另一方面，与记忆相关的γ波振荡主要在海马体中被报道，新皮层γ波在记忆中的作用仍未得到充分探索。在当前研究中，我们探究了记忆准确性和记忆信心的独特变异性如何导致θ波和γ波功率的波动。为此，我们在54名参与者执行源记忆任务时记录了脑电图。从这个任务中，我们获得了他们的项目记忆准确性、源记忆准确性、项目记忆信心和源记忆信心。这些行为指标被纳入逐次试验的线性混合效应模型，以揭示它们对额叶和顶叶区域振荡功率的独特贡献。我们的结果与θ波振荡参与记忆准确性和信心一致，但似乎表明θ波振荡在与记忆相关的信心中起主要作用。此外，我们发现γ波振荡在记忆处理中发挥着各种作用，这取决于脑区。
