Skinner Darlene M, Martin Gerard M, Wright Sandra L, Tomlin Julian, Odintsova Irina V, Thorpe Christina M, Harley Carolyn W, Marrone Diano F
Department of Psychology, Memorial University of Newfoundland, St John's, Newfoundland, Canada.
Hippocampus. 2014 Apr;24(4):396-402. doi: 10.1002/hipo.22233. Epub 2013 Dec 24.
Response reversal learning is facilitated in many species, including humans, when competing responses occur in separate contexts. This suggests hippocampal maps may facilitate the acquisition of competing responses and is consistent with the hypothesis that contextual encoding permits rapid acquisition of new behaviors in similar environments. To test this hypothesis, the pattern of Arc expression was examined after rats completed a series of left/right response reversals in a T-maze. This reversal training occurred in the same room, two different rooms, or within a single room but with the maze enclosed in wall-length curtains of different configurations (i.e., black/white square or circle). Across CA1 and CA3, successive T-maze exposures in the same room recruited the same cells to repeatedly transcribe Arc, while a unique population of cells transcribed Arc in response to each of two different rooms as well as to the two unique curtain configurations in the same room. The interference from original learning that was evident on the first reversal in animals without a context switch was absent in groups that experienced changes in room or curtain configuration. However, only the use of unique rooms, and not changes in the curtained enclosure, facilitated learning across response reversals relative to the groups exposed to only one room. Thus, separate hippocampal maps appear to provide protection from the original learning interference but do not support improved reversals over trials. The present data suggest changes in heading direction input, rather than remapping, are the source of facilitation of reversal learning.
当竞争性反应在不同情境中发生时，包括人类在内的许多物种的反应逆转学习都会得到促进。这表明海马体图谱可能有助于习得竞争性反应，并且与情境编码允许在相似环境中快速习得新行为的假设相一致。为了验证这一假设，在大鼠完成T迷宫中的一系列左右反应逆转后，检测了Arc表达模式。这种逆转训练在同一个房间、两个不同房间或在一个房间内进行，但迷宫被不同配置（即黑白方形或圆形）的全长窗帘包围。在CA1和CA3区域，在同一个房间中连续暴露于T迷宫会招募相同的细胞来反复转录Arc，而在两个不同房间以及同一个房间内的两种独特窗帘配置的每一种情况下，都会有独特的细胞群体转录Arc。在没有情境切换的动物中，第一次逆转时明显的原始学习干扰在经历房间或窗帘配置变化的组中不存在。然而，相对于仅暴露于一个房间的组，只有使用独特的房间，而不是带窗帘围栏的变化，才有助于跨反应逆转的学习。因此，单独的海马体图谱似乎能提供免受原始学习干扰的保护，但并不支持在试验中改善逆转。目前的数据表明，头部方向输入的变化而非重新映射是促进逆转学习的来源。
