Rita Levi-Montalcini Department of Neuroscience, University of Turin, I-10125 Turin, Italy.
Cereb Cortex. 2021 Oct 22;31(12):5381-5395. doi: 10.1093/cercor/bhab165.
Traumatic memories may become less precise over time and lead to the development of fear responses to novel stimuli, a process referred to as time-dependent fear generalization. The conditions that cause the growth of fear generalization over time are poorly understood. Here, we found that, in male rats, the level of discrimination at the early time point contributes to determining whether fear generalization will develop with the passage of time or not, suggesting a link between the precision of recent memory and the stability of remote engrams. We also found that the expression of insulin-like growth factor 2 receptor in layer 2/3 of the auditory cortex is linked to the precision of recent memories and to the stability of remote engrams and the development of fear generalization over time. These findings provide new insights on the neural mechanisms that underlie the time-dependent development of fear generalization that may occur over time after a traumatic event.
创伤性记忆可能随着时间的推移而变得不那么精确，并导致对新刺激产生恐惧反应，这个过程被称为时间依赖的恐惧泛化。导致恐惧泛化随时间增长的条件还不太清楚。在这里，我们发现，在雄性大鼠中，早期时间点的辨别能力有助于确定恐惧泛化是否会随着时间的推移而发展，这表明近期记忆的精确性和远程记忆印痕的稳定性之间存在联系。我们还发现，胰岛素样生长因子 2 受体在听觉皮层的 2/3 层的表达与近期记忆的精确性以及远程记忆印痕的稳定性和随时间推移的恐惧泛化的发展有关。这些发现为创伤事件后随时间推移可能发生的恐惧泛化的时间依赖性发展的神经机制提供了新的见解。
