Memory reorganization in the ACC and thalamus

在上个世纪，记忆一直是许多研究的焦点，但仍有许多不清楚的地方。科学家们发现，随着时间的推移，记忆会通过一种称为巩固的过程稳定下来。已提议存在两种类型的合并。第一种类型是细胞固结，发生在几分钟到几个小时内，被认为涉及重新连接神经细胞之间的连接。第二种类型是系统整合，它涉及在更长的时间范围内在全球大脑结构层面上的额外变化。因此，最初依赖于一种名为海马体的大脑结构的记忆，随着时间的推移变得依赖于其他结构。一个多世纪以来，科学家们相信巩固的记忆是永久稳定的，这意味着记忆只在两个层面上巩固一次。然而，最近的发现表明，当一个巩固的记忆被记住时，它可以返回到不稳定的状态。在这种状态下，可以通过称为重新巩固的过程来改变、擦除或重新稳定记忆。当记忆不再依赖于海马体时，这种现象也可能发生在系统层面(系统重新巩固)。因此，细胞和系统重新整合的这些发现挑战了整合的标准观点。最近，一些研究表明，内侧前额叶皮质(MPFC)中的特定区域，如前扣带回(ACC)，介导了远程记忆的提取。此外，层内丘脑核(ILN)是另一种称为丘脑的大脑结构中的一组核，最近也被证明参与系统的巩固。然而，ACC和ILN在细胞和系统再巩固中的作用尚未被研究。因此，这项建议将结合行为学和分子研究来测试ACC和ILN是否经历细胞和系统的重新整合。这将提供对这些过程的更好理解，以及关于这些大脑结构如何定期共同发挥作用的知识。

Memory has been the focus of a lot of research in the last century, but much is still not understood. Scientists have found that memories are stabilized over time through a process called consolidation. Two types of consolidation have been proposed to exist. The first type, cellular consolidation, occurs over minutes to hours and is thought to involve rewiring the connections between nerve cells. The second type, systems consolidation, involves additional changes at the global level of brain structures over a much longer time frame. As such, memories that are initially dependent on a brain structure called the hippocampus become dependent on other structures over time. For over a century, scientists believed that consolidated memories were permanently stabilized, implying that memories were consolidated at both levels only once. However, recent findings have shown that a consolidated memory can return to an unstable state when it when it is remembered. In this state, the memory can be altered, erased or restabilized through a process called reconsolidation. This phenomenon can also take place at the systems level (systems reconsolidation), when a memory no longer depends on the hippocampus. These findings of cellular and systems reconsolidation have thus challenged the standard view of consolidation. Recently, a number of studies have shown that specific regions in what is called the medial prefrontal cortex (mPFC), such as the anterior cingulate cortex (ACC), mediate retrieval of remote memories. Furthermore, the intralaminar thalamic nuclei (ILN), a group of nuclei in another brain structure called the thalamus, have also recently been shown to be involved in systems consolidation. However, the roles of the ACC and the ILN in cellular and systems reconsolidation have not yet been investigated. This proposal will therefore combine behavioral and molecular studies to test whether the ACC and ILN undergo cellular and systems reconsolidation. This would provide a better understanding of these processes, as well as knowledge on how these brain structures function together on a regular basis.