Dusek J A, Eichenbaum H
Department of Psychology, Boston University, Massachusetts 02215, USA.
Behav Neurosci. 1998 Aug;112(4):762-71. doi: 10.1037//0735-7044.112.4.762.
Normal rats and rats with hippocampal system damage were trained on a novel, olfactory version of the transverse-patterning task that involved the concurrent learning and continued performance of 3 partially ambiguous discrimination problems (A+B-, B+C-, C+A-). Animals with lesions of the fornix or perirhinal-entorhinal cortex acquired at least as rapidly as normal rats these problems presented in sequential blocks of trials involving the same stimulus pair. All groups also performed well on an initial test session when the order of stimulus pair presentations was randomized. Normal rats continued to discriminate appropriately in additional testing sessions with trials presented in random order. By contrast, both groups with hippocampal system damage performed poorly in continued random-order testing. These results extend the generality of the deficit in transverse patterning to the olfactory modality and demonstrate that the deficit is equivalent in magnitude after fornix or perirhinal-entorhinal damage. Findings also suggest that the transverse-patterning problem can be acquired transiently without critical hippocampal involvement, although continued performance relies on hippocampal function.
正常大鼠和海马系统受损的大鼠接受了一种新颖的嗅觉版横向模式任务训练，该任务涉及同时学习和持续执行3个部分模糊的辨别问题（A+B-、B+C-、C+A-）。穹窿或鼻周-内嗅皮质受损的动物学习这些在涉及相同刺激对的连续试验块中呈现的问题的速度至少与正常大鼠一样快。当刺激对呈现顺序随机化时，所有组在初始测试阶段也表现良好。正常大鼠在随后以随机顺序呈现试验的额外测试阶段继续进行适当的辨别。相比之下，海马系统受损的两组在持续的随机顺序测试中表现不佳。这些结果将横向模式缺陷的普遍性扩展到嗅觉模式，并表明穹窿或鼻周-内嗅皮质受损后缺陷程度相当。研究结果还表明，横向模式问题可以在没有关键海马参与的情况下短暂习得，尽管持续表现依赖于海马功能。
