Parallel emergence of stable and dynamic memory engrams in the hippocampus.
Parallel emergence of stable and dynamic memory engrams in the hippocampus.
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DOI：
10.1038/s41586-018-0191-2
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发表时间：
2018-06
期刊：
影响因子：
64.8
通讯作者：
Bartos M
中科院分区：
文献类型：
--
作者：
Hainmueller T;Bartos M
在我们的日常生活中，我们依靠对过去经历的记忆来计划未来的行为。这些记忆是由特定的神经元群或“记忆痕迹”的活动来表示的。神经元印记在学习过程中通过突触修饰进行组装，印记重新激活代表记忆的经验。有意识的记忆最初在海马体中储存几天，然后转移到皮层区域。在海马齿状回，颗粒细胞将来自内嗅皮层的丰富输入转化为稀疏输出，并将其转发到海马CA 3区高度互连的锥体细胞网络。CA 3锥体神经元投射到海马输出区CA 1。与海马体中瞬时记忆存储的想法一致，CA 1和CA 2中的记忆痕迹不会随着时间的推移而稳定。尽管如此，即使在几周后，齿状陀螺中的痕迹的重新激活也可以诱发人工记忆的回忆。要解决这一明显的矛盾，需要在整个学习过程中记录齿状回颗粒细胞，而迄今为止，这种记录还没有超过一天。在这里，我们使用慢性双光子钙成像在头固定的小鼠在虚拟环境中执行一个多天的空间记忆任务，记录在所有主要的海马子领域的神经元活动。在我们的行为模式中，CA 1-CA 3区的锥体神经元表现出精确的、高度情境特异性的、但不断变化的空间场景表征，而齿状回中的颗粒细胞具有一种空间编码，这种编码在许多天内都是稳定的，具有低的地点特异性或情境特异性。我们的研究结果表明，突触的重量沿着海马三突触环不断重新分配，以支持在下游海马区的动态表示的基础上，由齿状回提供一个稳定的代码的形成。
During our daily life, we depend on memories of past experiences to plan future behaviour. These memories are represented by the activity of specific neuronal groups or 'engrams'. Neuronal engrams are assembled during learning by synaptic modification, and engram reactivation represents the memorized experience. Engrams of conscious memories are initially stored in the hippocampus for several days and then transferred to cortical areas. In the dentate gyrus of the hippocampus, granule cells transform rich inputs from the entorhinal cortex into a sparse output, which is forwarded to the highly interconnected pyramidal cell network in hippocampal area CA3 This process is thought to support pattern separation (but see refs.). CA3 pyramidal neurons project to CA1, the hippocampal output region. Consistent with the idea of transient memory storage in the hippocampus, engrams in CA1 and CA2 do not stabilize over time. Nevertheless, reactivation of engrams in the dentate gyros can induce recall of artificial memories even after weeks. Reconciliation of this apparent paradox will require recordings from dentate gyrus granule cells throughout learning, which has so far not been performed for more than a single day. Here, we use chronic two-photon calcium imaging in head-fixed mice performing a multiple-day spatial memory task in a virtual environment to record neuronal activity in all major hippocampal subfields. Whereas pyramidal neurons in CA1-CA3 show precise and highly context-specific, but continuously changing, representations of the learned spatial sceneries in our behavioural paradigm, granule cells in the dentate gyrus have a spatial code that is stable over many days, with low place- or context-specificity. Our results suggest that synaptic weights along the hippocampal trisynaptic loop are constantly reassigned to support the formation of dynamic representations in downstream hippocampal areas based on a stable code provided by the dentate gyms.
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DOI：
10.1073/pnas.1214107109
发表时间：
2012-11-20
影响因子：
11.1
作者：
Mankin, Emily A.;Sparks, Fraser T.;Leutgeb, Jill K.
通讯作者：
Leutgeb, Jill K.
影响因子：
3.5
作者：
Hosp, Jonas A.;Strueber, Michael;Yanagawa, Yuchio;Obata, Kunihiko;Vida, Imre;Jonas, Peter;Bartos, Marlene
通讯作者：
Bartos, Marlene
影响因子：
5.3
作者：
Bernier, Brian E.;Lacagnina, Anthony F.;Drew, Michael R.
通讯作者：
Drew, Michael R.
影响因子：
25
作者：
Dombeck, Daniel A.;Harvey, Christopher D.;Tian, Lin;Looger, Loren L.;Tank, David W.
通讯作者：
Tank, David W.
影响因子：
5.3
作者：
Arriaga, Moises;Han, Edward B.
通讯作者：
Han, Edward B.