Circadian time-place (or time-route) learning in rats with hippocampal lesions
Circadian time-place (or time-route) learning in rats with hippocampal lesions
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DOI：
10.1016/j.nlm.2016.09.004
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发表时间：
2016-12-01
影响因子：
2.7
通讯作者：
Mumby, Dave G.
中科院分区：
文献类型：
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作者：
Cole, Emily;Mistlberger, Ralph E.;Mumby, Dave G.
昼夜时间-地点学习（TPL）是记住发生重大事件的地点和生物时间的能力（例如，食物供应）。这种能力需要生物钟为认知系统提供相位信息（时间标签），这些认知系统参与将事件的表征与空间参考记忆联系起来。到目前为止，还不清楚哪些神经元基质在这一过程中是关键的，但一个候选结构是海马体（HPC）。HPC是必不可少的正常性能的任务，需要allocentric空间记忆，并表现出昼夜节律的基因表达是敏感的用餐时间。使用一种新的TPL训练程序和丰富的多维环境，我们训练大鼠找到一种食物奖励，这种奖励在两个位置之间变化，相对于一天中的时间。在大鼠获得任务后，它们接受HPC或SHAM损伤并重新测试。HPC病变的大鼠最初受损的任务相对于SHAM大鼠，但重新获得高分，继续测试。探针测试显示，老鼠没有使用交替策略或依赖于明暗转换来定位食物奖励。我们假设，短暂的中断和恢复反映了从HPC依赖的allocentric导航（学习的地方）背侧纹状体依赖的自我中心的空间导航（学习路线的位置）的开关。无论导航策略，这些结果表明，HPC是不需要的大鼠在不同的位置使用昼夜相位作为判别线索找到食物。(C)2016 Elsevier Inc. All rights reserved.
Circadian time-place learning (TPL) is the ability to remember both the place and biological time of day that a significant event occurred (e.g., food availability). This ability requires that a circadian clock provide phase information (a time tag) to cognitive systems involved in linking representations of an event with spatial reference memory. To date, it is unclear which neuronal substrates are critical in this process, but one candidate structure is the hippocampus (HPC). The HPC is essential for normal performance on tasks that require allocentric spatial memory and exhibits circadian rhythms of gene expression that are sensitive to meal timing. Using a novel TPL training procedure and enriched, multidimensional environment, we trained rats to locate a food reward that varied between two locations relative to time of day. After rats acquired the task, they received either HPC or SHAM lesions and were re-tested. Rats with HPC lesions were initially impaired on the task relative to SHAM rats, but re-attained high scores with continued testing. Probe tests revealed that the rats were not using an alternation strategy or relying on light-dark transitions to locate the food reward. We hypothesize that transient disruption and recovery reflect a switch from HPC-dependent allocentric navigation (learning places) to dorsal striatum-dependent egocentric spatial navigation (learning routes to a location). Whatever the navigation strategy, these results demonstrate that the HPC is not required for rats to find food in different locations using circadian phase as a discriminative cue. (C) 2016 Elsevier Inc. All rights reserved.