Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08540, USA; Institute for Mind and Biology, University of Chicago, Chicago, IL, 60637, USA; Department of Psychology, University of Chicago, Chicago, IL, 60637, USA.
Princeton Neuroscience Institute, Princeton University, Princeton, NJ, 08540, USA; Department of Psychology, Princeton University, Princeton, NJ, 08540, USA; Department of Psychology, Yale University, New Haven, CT, 06520, USA.
Neuroimage. 2019 Oct 15;200:292-301. doi: 10.1016/j.neuroimage.2019.06.001. Epub 2019 Jun 12.
Theories of mental context and memory posit that successful mental context reinstatement enables better retrieval of memories from the same context, at the expense of memories from other contexts. To test this hypothesis, we had participants study lists of words, interleaved with task-irrelevant images from one category (e.g., scenes). Following encoding, participants were cued to mentally reinstate the context associated with a particular list, by thinking about the images that had appeared between the words. We measured context reinstatement by applying multivariate pattern classifiers to fMRI, and related this to performance on a free recall test that followed immediately afterwards. To increase sensitivity, we used a closed-loop neurofeedback procedure, whereby higher classifier evidence for the cued category elicited increased visibility of the images from the studied context onscreen. Our goal was to create a positive feedback loop that amplified small fluctuations in mental context reinstatement, making it easier to experimentally detect a relationship between context reinstatement and recall. As predicted, we found that greater amounts of classifier evidence were associated with better recall of words from the reinstated context, and worse recall of words from a different context. In a second experiment, we assessed the role of neurofeedback in identifying this brain-behavior relationship by presenting context images again and manipulating whether their visibility depended on classifier evidence. When neurofeedback was removed, the relationship between classifier evidence and memory retrieval disappeared. Together, these findings demonstrate a clear effect of context reinstatement on memory recall and suggest that neurofeedback can be a useful tool for characterizing brain-behavior relationships.
心理语境和记忆的理论假设，成功的心理语境恢复能更好地从同一语境中检索记忆，而牺牲其他语境的记忆。为了检验这一假设，我们让参与者学习单词列表，穿插着来自一个类别（例如场景）的与任务无关的图像。在编码之后，参与者通过思考出现在单词之间的图像来提示心理恢复与特定列表相关的语境。我们通过对 fMRI 应用多元模式分类器来衡量语境恢复，并将其与紧随其后的自由回忆测试的表现相关联。为了提高灵敏度，我们使用了闭环神经反馈程序，其中提示类别更高的分类器证据会增加屏幕上所研究语境图像的可见度。我们的目标是创建一个正反馈循环，放大心理语境恢复中的微小波动，使实验更容易检测到语境恢复和回忆之间的关系。正如预测的那样，我们发现，更多的分类器证据与从恢复的语境中回忆单词的能力更强，而从不同语境中回忆单词的能力更差有关。在第二个实验中，我们通过再次呈现语境图像并操纵其可见性是否取决于分类器证据，来评估神经反馈在识别这种大脑-行为关系中的作用。当去除神经反馈时，分类器证据和记忆检索之间的关系就消失了。总之，这些发现表明，语境恢复对记忆回忆有明显影响，并表明神经反馈可以成为表征大脑-行为关系的有用工具。
