Dayawansa S, Kobayashi T, Hori E, Umeno K, Tazumi T, Ono T, Nishijo H
System Emotional Science, Graduate School of Medicine, University of Toyama, Sugitani 2630, Toyama 930-0194, Japan.
Hippocampus. 2006;16(7):586-95. doi: 10.1002/hipo.20186.
Previous studies reported context (or behavior)-dependent activities of hippocampal place cells, which are suggested to be the neural basis of episodic memory. However, it remains unclear what distinctive items these context-dependent activities encode. We investigated separately the effects of space, locomotion, and episodes with positive/negative reinforcements on activity of place-differential neurons in the hippocampal CA1 area. Rats were placed on a treadmill affixed to a motion stage translocated along a figure 8-shaped track. The track could be navigated by two different routes that shared a common central stem. The stage was paused at the start and end of the routes, where conditioned response tasks with different reinforcements were imposed. As the rats passed the common central stem, some neurons fired differently depending on the route. Comparison of hippocampal spatial firing patterns across different conditions with and without treadmill operation and/or the tasks indicated that these route-dependent spatial firing patterns were sensitive to locomotion, the tasks, and vestibular sensation or visual cues such as optic flow. The results suggest that external sensory inputs, path integration, and reinforcement context are all integrated in the hippocampus, which might provide the neural basis of episodic memory.
先前的研究报道了海马位置细胞的情境（或行为）依赖性活动，这些活动被认为是情景记忆的神经基础。然而，尚不清楚这些情境依赖性活动编码了哪些独特的信息。我们分别研究了空间、运动以及有正/负强化的情景对海马CA1区位置差异神经元活动的影响。将大鼠放置在固定于沿8字形轨道移动的运动平台上的跑步机上。该轨道可以通过两条共享一个公共中央主干的不同路径来导航。平台在路径的起点和终点暂停，在那里施加具有不同强化的条件反应任务。当大鼠经过公共中央主干时，一些神经元根据路径的不同而有不同的放电。比较有无跑步机操作和/或任务的不同条件下海马的空间放电模式表明，这些依赖于路径的空间放电模式对运动、任务以及前庭感觉或视觉线索（如光流）敏感。结果表明，外部感觉输入、路径整合和强化情境都在海马中整合，这可能为情景记忆提供神经基础。
