Lux Vanessa, Atucha Erika, Kitsukawa Takashi, Sauvage Magdalena M
Functional Architecture of Memory unit, Mercator Research Group, Medical Faculty, Ruhr University Bochum, Bochum, Germany.
Functional Neuroplasticity Department, Otto von Guericke University, Magdeburg, Germany.
Elife. 2016 Feb 12;5:e11862. doi: 10.7554/eLife.11862.
Whether retrieval still depends on the hippocampus as memories age or relies then on cortical areas remains a major controversy. Despite evidence for a functional segregation between CA1, CA3 and parahippocampal areas, their specific role within this frame is unclear. Especially, the contribution of CA3 is questionable as very remote memories might be too degraded to be used for pattern completion. To identify the specific role of these areas, we imaged brain activity in mice during retrieval of recent, early remote and very remote fear memories by detecting the immediate-early gene Arc. Investigating correlates of the memory trace over an extended period allowed us to report that, in contrast to CA1, CA3 is no longer recruited in very remote retrieval. Conversely, we showed that parahippocampal areas are then maximally engaged. These results suggest a shift from a greater contribution of the trisynaptic loop to the temporoammonic pathway for retrieval.
随着记忆的老化，检索是否仍依赖海马体，还是转而依赖皮质区域，这仍然是一个主要的争议点。尽管有证据表明CA1、CA3和海马旁区域之间存在功能分离，但其在这一框架内的具体作用尚不清楚。特别是，CA3的作用值得怀疑，因为非常久远的记忆可能已经退化到无法用于模式完成。为了确定这些区域的具体作用，我们通过检测即刻早期基因Arc，对小鼠在检索近期、早期远期和非常远期恐惧记忆时的大脑活动进行了成像。对记忆痕迹在较长时间内的相关性进行研究，使我们能够报告，与CA1不同，CA3在非常远期的检索中不再被激活。相反，我们发现海马旁区域此时处于最大程度的参与状态。这些结果表明，在检索过程中，从三突触回路的更大贡献向颞叶-海马通路发生了转变。
