Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20814, USA; Department of Psychology, The University of Chicago, Chicago, IL 60637, USA.
Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20814, USA; Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA.
Cortex. 2023 Jan;158:71-82. doi: 10.1016/j.cortex.2022.08.014. Epub 2022 Oct 21.
The recall and visualization of people and places from memory is an everyday occurrence, yet the neural mechanisms underpinning this phenomenon are not well understood. In particular, the temporal characteristics of the internal representations generated by active recall are unclear. Here, we used magnetoencephalography (MEG) and multivariate pattern analysis to measure the evolving neural representation of familiar places and people across the whole brain when human participants engage in active recall. To isolate self-generated imagined representations, we used a retro-cue paradigm in which participants were first presented with two possible labels before being cued to recall either the first or second item. We collected personalized labels for specific locations and people familiar to each participant. Importantly, no visual stimuli were presented during the recall period, and the retro-cue paradigm allowed the dissociation of responses associated with the labels from those corresponding to the self-generated representations. First, we found that following the retro-cue it took on average ∼1000 ms for distinct neural representations of freely recalled people or places to develop. Second, we found distinct representations of personally familiar concepts throughout the 4 s recall period. Finally, we found that these representations were highly stable and generalizable across time. These results suggest that self-generated visualizations and recall of familiar places and people are subserved by a stable neural mechanism that operates relatively slowly when under conscious control.
从记忆中回忆和可视化人与物是日常生活中常见的现象，但这一现象背后的神经机制尚未被很好地理解。特别是，主动回忆产生的内部表示的时间特征尚不清楚。在这里，我们使用脑磁图（MEG）和多元模式分析来测量人类参与者进行主动回忆时整个大脑中熟悉的地方和人的内在表示的演变。为了分离自我生成的想象表示，我们使用了回溯提示范式，其中参与者首先呈现两个可能的标签，然后提示他们回忆第一个或第二个项目。我们为每个参与者熟悉的特定地点和人收集个性化标签。重要的是，在回忆期间没有呈现视觉刺激，回溯提示范式允许将与标签相关的反应与那些与自我生成的表示相对应的反应分离。首先，我们发现，回溯提示后，平均需要约 1000 毫秒才能形成自由回忆的人和物的独特神经表示。其次，我们发现个人熟悉的概念在 4 秒的回忆期间有独特的表示。最后，我们发现这些表示非常稳定且具有跨时间的可转移性。这些结果表明，熟悉的人和物的自我生成的可视化和回忆是由一种稳定的神经机制支持的，当受到意识控制时，这种机制的运作速度相对较慢。
