The role of novelty and surprise in aversive conditioning

摘要 人们很早就知道，新奇和惊喜有助于学习和记忆。在功能层面上，这是有意义的； 必须了解意外事件，以便在未来能够适当地预测和应对这些事件。在一次 在心理层面上，令人惊讶的事件被证明可以增强记忆，因为它们会引发排练。受试者倾向于 在意外事件发生后，比起熟悉的事件，更多地去“思考”。这在人类身上已经直接观察到了。 (外显排练)和间接动物体内(内隐排练)。在这两种情况下，记忆增强可以是 通过在新奇事件之后立即呈现的分心刺激来扰乱排练来消除。 几分钟后呈现同样的分心刺激没有任何效果。这表明排练是短暂的，而且 不同于记忆巩固的过程，记忆巩固过程在学习后将新信息稳定几个小时。在……里面 除了增加排练，新奇的活动还会触发去甲肾上腺素(NE)和多巴胺(DA)的释放，这两种物质 都能增强突触的可塑性。阻断海马体中这些神经调节剂的受体可以防止 阻止动物形成新的空间和背景记忆。基于这些发现，我们假设令人惊讶的是 事件增强记忆是因为它们在海马体活跃的同时诱导儿茶酚胺的释放 排练/重播新信息。我们的初步数据表明，NE和DA都在 在出现意想不到的厌恶刺激期间和之后，海马体。与此同时，还有一个增长 在尖波纹波振荡(SWR)中，已知包含最近遇到的刺激的重放序列。 因此，我们将通过实时监测和操纵儿茶酚胺的释放来检验上述假设 在厌恶的学习任务中，同时记录海马区的振荡和单个单位的活动。

Abstract Novelty and surprise have long been known to facilitate learning and memory. At a functional level this makes sense; unexpected events have to be learned about so they can be predicted and responded to appropriately in the future. At a psychological level, surprising events have been shown to enhance memory because they induce rehearsal. Subjects tend to “think about” unexpected events more than familiar ones after they occur. This has been observed directly in humans (explicit rehearsal) and indirectly in animals (implicit rehearsal). In both cases, the memory enhancement can be eliminated by disrupting rehearsal with a distractor stimulus that is presented immediately after the novel event. Presenting the same distractor stimulus several minutes later has no effect. This suggests rehearsal is short-lasting and distinct from the process of memory consolidation, which stabilizes new information for several hours after learning. In addition to increasing rehearsal, novel events also trigger the release of norepinephrine (NE) and dopamine (DA), which are known to enhance synaptic plasticity. Blocking receptors for these neuromodulators in the hippocampus prevents animals from forming new spatial and contextual memories. Based on these findings, we hypothesize that surprising events enhance memory because they induce catecholamine release at the same time the hippocampus is actively rehearsing/replaying new information. Our preliminary data demonstrate that NE and DA are both released in the hippocampus during and after the presentation of an unexpected aversive stimulus. At the same time, there is an increase in sharp-wave ripple oscillations (SWRs), which are known to contain replay sequences for recently encountered stimuli. Consequently, we will test the hypothesis above by monitoring and manipulating catecholamine release in real-time during an aversive learning task while simultaneously recording oscillations and single unit activity in the hippocampus.