第七章 学习与记忆.pptVIP

学习、记忆与健忘症 记忆的局部表征 海马与健忘症 海马的记忆功能 阿尔兹海默症 学习和记忆过程中脑内会发生哪些改变？ Lashley寻找记忆痕迹（Engram） FIRST,Lashley reasoned that if learning depends on new or strengthened connections between two brain areas, a knife cut somewhere in the brain should interrupt that connection and abolish the learned response. He trained rats on mazes and a brightness discrimination task and then made deep cuts in varying locations in their cerebral cortices. However, no knife cut significantly impaired the rats’ performances. Evidently, the types of learning that he studied did not depend on connections across the cortex. THEN, Lashley tested whether any portion of the cerebral cortex（脑皮层） is more important than others for learning. He trained rats on mazes（迷宫训练） before or after he removed large portions of the cortex. The lesions（损伤） impaired performance, but the amount of retardation depended more on the amount of brain damage than on its location. Learning and memory apparently did not rely on a single cortical area. Lashley therefore proposed two principles about the nervous system: ■ Equipotentiality（等势说）—all parts of the cortex contribute equally to complex behaviors such as learning, and any part of the cortex can substitute for any other. ■Mass action（整体活动说）—the cortex works as a whole, and more cortex is better. 对记忆痕迹的进一步有哪些信誉好的足球投注网站 Richard F. Thompson and his colleagues sought the engram of memory not in the cerebral cortex（脑皮层） but in the cerebellum（小脑）. Thompson and colleagues studied classical conditioning of eyelid responses in rabbits. They presented first a tone (CS) and then a puff of air (UCS) to the cornea（角膜） of the rabbit’s eye. At first, a rabbit blinked at the airpuff but not at the tone. After repeated pairings, classical conditioning occurred and the rabbit blinked at the tone also. Investigators recorded the activity in various brain cells to determine which ones changed their responses during learning. Imagine a sequence of brain areas from the sensory receptors to the motor neuro