NIMH-UCL Joint Neuroscience Graduate Partnership Program, National Institute of Mental Health, Bethesda, Maryland; Section on Functional Imaging Methods, Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, Maryland; University College London, Institute of Cognitive Neuroscience, Alexandra House, London, WC1N 3AR, United Kingdom; University College London, Institute of Neurology, London, WC1N 1PJ, United Kingdom.
Hippocampus. 2014 Jun;24(6):656-65. doi: 10.1002/hipo.22255. Epub 2014 Feb 18.
Memory retrieval is believed to involve a disparate network of areas, including medial prefrontal and medial temporal cortices, but the mechanisms underlying their coordination remain elusive. One suggestion is that oscillatory coherence mediates inter-regional communication, implicating theta phase and theta-gamma phase-amplitude coupling in mnemonic function across species. To examine this hypothesis, we used non-invasive whole-head magnetoencephalography (MEG) as participants retrieved the location of objects encountered within a virtual environment. We demonstrate that, when participants are cued with the image of an object whose location they must subsequently navigate to, there is a significant increase in 4-8 Hz theta power in medial prefrontal cortex (mPFC), and the phase of this oscillation is coupled both with ongoing theta phase in the medial temporal lobe (MTL) and perceptually induced 65-85 Hz gamma amplitude in medial parietal cortex. These results suggest that theta phase coupling between mPFC and MTL and theta-gamma phase-amplitude coupling between mPFC and neocortical regions may play a role in human spatial memory retrieval.
记忆检索被认为涉及到包括内侧前额叶和内侧颞叶皮层在内的离散网络区域，但它们协调的机制仍然难以捉摸。一种观点认为，振荡相干性介导了区域间的通讯，暗示theta 相位和 theta-伽马相位-幅度耦合在记忆功能上具有跨物种的作用。为了检验这一假设，我们使用非侵入性的全头磁脑图 (MEG) 作为参与者检索他们在虚拟环境中遇到的物体的位置。我们证明，当参与者被提示要记住他们必须随后导航到的物体的图像时，内侧前额叶皮层 (mPFC) 中的 4-8 Hz theta 功率显著增加，并且这种振荡的相位与内侧颞叶 (MTL) 中的持续 theta 相位以及内侧顶叶皮层 (MPC) 中感知诱导的 65-85 Hz gamma 幅度都有关联。这些结果表明，mPFC 和 MTL 之间的 theta 相位耦合以及 mPFC 和新皮层区域之间的 theta-伽马相位-幅度耦合可能在人类空间记忆检索中发挥作用。
