Wellcome Centre for Integrative Neuroimaging, University of Oxford, FMRIB, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
Wellcome Centre for Integrative Neuroimaging, University of Oxford, FMRIB, John Radcliffe Hospital, Oxford, OX3 9DU, UK; School of Health Sciences, Purdue University, IN 47907, USA.
Neuron. 2019 Feb 6;101(3):528-541.e6. doi: 10.1016/j.neuron.2018.11.042. Epub 2018 Dec 20.
Our experiences often overlap with each other, yet we are able to selectively recall individual memories to guide decisions and future actions. The neural mechanisms that support such precise memory recall remain unclear. Here, using ultra-high field 7T MRI we reveal two distinct mechanisms that protect memories from interference. The first mechanism involves the hippocampus, where the blood-oxygen-level-dependent (BOLD) signal predicts behavioral measures of memory interference, and representations of context-dependent memories are pattern separated according to their relational overlap. The second mechanism involves neocortical inhibition. When we reduce the concentration of neocortical GABA using trans-cranial direct current stimulation (tDCS), neocortical memory interference increases in proportion to the reduction in GABA, which in turn predicts behavioral performance. These findings suggest that memory interference is mediated by both the hippocampus and neocortex, where the hippocampus separates overlapping but context-dependent memories using relational information, and neocortical inhibition prevents unwanted co-activation between overlapping memories.
我们的经验经常相互重叠，但我们能够有选择地回忆个人记忆，以指导决策和未来的行动。支持这种精确记忆回忆的神经机制尚不清楚。在这里，我们使用超高场 7T MRI 揭示了两种保护记忆免受干扰的独特机制。第一种机制涉及海马体，其中血氧水平依赖（BOLD）信号预测记忆干扰的行为测量，并且根据它们的关系重叠对上下文相关记忆的表示进行模式分离。第二种机制涉及新皮层抑制。当我们使用经颅直流电刺激（tDCS）降低新皮层 GABA 的浓度时，新皮层记忆干扰与 GABA 减少成比例增加，这反过来又预测了行为表现。这些发现表明，记忆干扰是由海马体和新皮层介导的，其中海马体使用关系信息分离重叠但上下文相关的记忆，而新皮层抑制防止重叠记忆之间不必要的共同激活。
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