Zola-Morgan S M, Squire L R
Veterans Affairs Medical Center, San Diego, CA.
Science. 1990 Oct 12;250(4978):288-90. doi: 10.1126/science.2218534.
Clinical and experimental studies have shown that the hippocampal formation and related structures in the medial temporal lobe are important for learning and memory. Retrograde amnesia was studied prospectively in monkeys to understand the contribution of the hippocampal formation to memory function. Monkeys learned to discriminate 100 pairs of objects beginning 16, 12, 8, 4, and 2 weeks before the hippocampal formation was removed (20 different pairs at each time period). Two weeks after surgery, memory was assessed by presenting each of the 100 object pairs again for a single-choice trial. Normal monkeys exhibited forgetting; that is, they remembered recently learned objects better than objects learned many weeks earlier. Monkeys with hippocampal damage were severely impaired at remembering recently learned objects. In addition, they remembered objects learned long ago as well as normal monkeys did and significantly better than they remembered objects learned recently. These results show that the hippocampal formation is required for memory storage for only a limited period of time after learning. As time passes, its role in memory diminishes, and a more permanent memory gradually develops independently of the hippocampal formation, probably in neocortex.
临床和实验研究表明，内侧颞叶中的海马结构及相关结构对学习和记忆很重要。为了了解海马结构对记忆功能的作用，对猴子进行了前瞻性逆行性遗忘研究。在切除海马结构前16周、12周、8周、4周和2周，猴子开始学习辨别100对物体（每个时间段有20对不同物体）。手术后两周，通过再次呈现这100对物体进行单项选择试验来评估记忆。正常猴子表现出遗忘现象；也就是说，它们对近期学习的物体的记忆比对几周前学习的物体的记忆更好。海马受损的猴子在记忆近期学习的物体方面严重受损。此外，它们对很久以前学习的物体的记忆与正常猴子一样好，而且明显比对近期学习的物体的记忆好。这些结果表明，海马结构在学习后仅在有限的时间段内对记忆存储是必需的。随着时间的推移，它在记忆中的作用逐渐减弱，一种更持久的记忆可能在新皮层中逐渐独立于海马结构而形成。
