Hunsaker Michael R, Allan Kimberly D, Kesner Raymond P
Department of Psychology, University of Utah, Salt Lake City, Utah 84112, USA.
Hippocampus. 2007;17(6):494-502. doi: 10.1002/hipo.20288.
Dorsal CA3, but not dorsal CA1, lesioned rats are impaired in the acquisition of a delay nonmatch to place task. In this study, dorsal CA3 efferent fibers in the fimbria were transected; while taking care to spare afferent fibers from the medial septum. Neurophysiological, anatomical tracing, and histochemical data suggest that the transection was selective to dorsal CA3 efferent fibers and spared afferents from the medial septum. Rats showed a deficit for acquisition, but not for performance once learned. One possible explanation is that a small change to the cholinergic inputs to dCA3 caused by a decrease in dorsal CA3 efferent signals reaching the medial septum may impair new learning but not performance of a task once learned.
背侧CA3而非背侧CA1受损的大鼠在延迟位置不匹配任务的习得过程中表现受损。在本研究中，穹窿中的背侧CA3传出纤维被横断，同时注意保留来自内侧隔核的传入纤维。神经生理学、解剖学追踪和组织化学数据表明，横断对背侧CA3传出纤维具有选择性，保留了来自内侧隔核的传入纤维。大鼠在习得方面表现出缺陷，但一旦学会，在任务执行方面则没有缺陷。一种可能的解释是，到达内侧隔核的背侧CA3传出信号减少导致对背侧CA3胆碱能输入的微小变化，这可能会损害新的学习，但不会影响已学会任务的执行。
