Kavli Institute for Systems Neuroscience, Centre for Neural Computation, The Egil and Pauline Braathen and Fred Kavli Centre for Cortical Microcircuits, Norwegian University of Science and Technology, Trondheim, Norway.
Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA.
Nat Neurosci. 2021 Jun;24(6):863-872. doi: 10.1038/s41593-021-00835-3. Epub 2021 Apr 15.
To guide spatial behavior, the brain must retrieve memories that are appropriately associated with different navigational contexts. Contextual memory might be mediated by cell ensembles in the hippocampal formation that alter their responses to changes in context, processes known as remapping and realignment in the hippocampus and entorhinal cortex, respectively. However, whether remapping and realignment guide context-dependent spatial behavior is unclear. To address this issue, human participants learned object-location associations within two distinct virtual reality environments and subsequently had their memory tested during functional MRI (fMRI) scanning. Entorhinal grid-like representations showed realignment between the two contexts, and coincident changes in fMRI activity patterns consistent with remapping were observed in the hippocampus. Critically, in a third ambiguous context, trial-by-trial remapping and realignment in the hippocampal-entorhinal network predicted context-dependent behavior. These results reveal the hippocampal-entorhinal mechanisms mediating human contextual memory and suggest that the hippocampal formation plays a key role in spatial behavior under uncertainty.
为了指导空间行为，大脑必须检索与不同导航情境相关的适当记忆。情境记忆可能由海马体结构中的细胞集合介导，这些细胞集合改变了它们对情境变化的反应，这一过程分别被称为海马体和内嗅皮层中的重映射和重新校准。然而，重映射和重新校准是否指导情境相关的空间行为尚不清楚。为了解决这个问题，人类参与者在两个不同的虚拟现实环境中学习了物体-位置的关联，然后在功能磁共振成像（fMRI）扫描期间对他们的记忆进行了测试。内嗅皮层的网格状表示在两个情境之间显示出了重新校准，并且在海马体中观察到与重映射一致的 fMRI 活动模式的一致变化。关键的是，在第三个模糊情境中，海马体-内嗅皮层网络中的逐次重映射和重新校准预测了情境相关的行为。这些结果揭示了介导人类情境记忆的海马体-内嗅皮层机制，并表明海马体在不确定条件下的空间行为中起着关键作用。
