Perirhinal and postrhinal contributions to remote memory for context
Perirhinal and postrhinal contributions to remote memory for context
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DOI：
10.1523/jneurosci.3781-04.2004
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发表时间：
2004-12-08
影响因子：
5.3
通讯作者：
Jutras, MJ
中科院分区：
文献类型：
--
作者：
Burwell, RD;Bucci, DJ;Jutras, MJ
内侧颞叶记忆系统的两个组成部分，即嗅周皮层（PER）和嗅后皮层（POR），与海马直接或通过内嗅皮层相连。在背景恐惧条件反射任务训练之前或之后不久，PER或POR的损伤会导致随后的背景恐惧表达的缺陷，这意味着这些区域参与了背景记忆的获得或表达。在这里，我们研究的贡献PER和POR远程学习的上下文信息的处理。雄性Long-Evans大鼠在无信号的情境恐惧条件化范式中进行训练。训练后，大鼠接受双侧神经毒性病变PER或POR或假对照手术在三个不同的训练病变的时间间隔：1，28，或100天后的培训。手术后两周，损伤和对照大鼠返回到训练环境中，以评估通过冻结测量的背景恐惧。与对照组大鼠相比，PER或POR损伤的大鼠在训练环境中冻结显着减少，但彼此没有差异。对于任何组，训练至病变间隔的缺陷严重程度均无差异。这种模式的赤字不同的训练后海马病变，较长的训练病变的间隔产生显着更多的恐惧条件的上下文冻结比较短的训练病变的间隔。在本研究中没有这样一个逆行梯度，我们的解释是，PER和POR在存储或检索的代表性的上下文有一个持续的作用。或者，这些区域可能参与更广泛的巩固过程，在学习后超过100天变得明显。
The perirhinal ( PER) and postrhinal (POR) cortices, two components of the medial temporal lobe memory system, are reciprocally connected with the hippocampus both directly and via the entorhinal cortex. Damage to PER or POR before or shortly after training on a contextual fear conditioning task causes deficits in the subsequent expression of contextual fear, implicating these regions in the acquisition or expression of contextual memory. Here, we examined the contribution of PER and POR to the processing of remotely learned contextual information. Male Long-Evans rats were trained in an unsignaled contextual fear conditioning paradigm. After training, rats received bilateral neurotoxic lesions to PER or POR or sham control surgeries at three different training-to-lesion intervals: 1, 28, or 100 d after training. Two weeks after surgery, lesioned and control rats were returned to the training context to assess contextual fear as measured by freezing. Rats with PER or POR damage froze significantly less in the training context than control rats but were not different from each other. The severity of the deficit did not differ across training-to-lesion intervals for any group. This pattern of deficits differs from that of posttraining hippocampal lesions, for which longer training-to-lesion intervals produce significantly more fear-conditioned contextual freezing than shorter training-to-lesion intervals. In the absence of such a retrograde gradient in the present study, our interpretation is that PER and POR have an ongoing role in the storage or retrieval of representations for context. Alternatively, these regions may be involved in a more extended consolidation process that becomes apparent beyond 100 d after learning.