Spontaneous activity, memory replay and the default mode network

自发活动占了大脑活动的大部分，很可能是大脑信息处理的关键，但它的功能仍然相当神秘。两个关键的自发活动过程是默认模式网络(DMN)和记忆重播(Memory Replay)，默认模式网络(DMN)是一组在行为空闲期间最显著连接和活跃的区域，记忆重播是在体验过程中发生的神经模式的自发重新激活。我将测试DMN在记忆重放过程中扮演关键角色的假设。如果这一理论得到证实，将为记忆研究带来重要的概念性进展，因为它将提供一种支持复杂记忆表征形成和巩固的机制。在默认模式网络领域，由于重放可以被用作破译DMN执行的计算的“罗塞塔石头”，超越了DMN研究的典型焦点--连通性、动力学和认知相关性。我将通过对整个小鼠皮质自发神经活动的实验研究来探索这一理论，从单个神经元规模的大视野双光子成像和高容量电生理学，到运行记忆任务的动物的全皮质光学成像。我将通过量化传达的信息并评估其性质来表征网络动态以及记忆的编码和回放。我还将测量这些网络中的关键行为，并测试自发活动中发生的神经元雪崩是否在跨越遥远的大脑区域传递信息方面发挥作用。

Spontaneous activity accounts for most of what the brain does and is likely to be key for information processing in the brain, but its function is still quite mysterious. Two key spontaneous activity processes are the Default Mode Network (DMN), a set of areas that are most markedly connected and active during behavioural idleness, and memory replay, the spontaneous reactivation of neural patterns occurring during experience. I will test the hypothesis that the DMN plays a key role in memory replay processes. This theory, if confirmed, would bring important conceptual advances: to memory studies, as it would provide a mechanism supporting the formation and consolidation of complex memory representations. To the Default Mode Network field, as replay can be used as the "Rosetta Stone" to decipher the computations the DMN performs, moving beyond the connectivity, dynamics, and cognitive correlates, typical focus of DMN research. I will explore this theory by an experimental study of spontaneous neural activity over the whole mouse cortex, going from large field-of-view 2-photon imaging and high-volume electrophysiology for the single neuron scale, to whole-cortex optical imaging in animals running memory tasks. I will characterize the network dynamics and the encoding and replay of memories by quantifying conveyed information and assessing its nature. I will also measure critical behaviour in these networks, and test whether neuronal avalanches, that occur in spontaneous activity, play a role in conveying information across distant brain areas.