Woolf N J
Department of Psychology, University of California, Los Angeles 90095-1563, USA.
Neurobiol Learn Mem. 1996 Nov;66(3):258-66. doi: 10.1006/nlme.1996.0068.
It has been known for a long time that cholinergic basal forebrain neurons which project to the cerebral cortex play a role in learning and memory. Behavioral studies following lesions, for example, repeatedly have suggested multiple learning-related roles for these neurons. Apart from behavioral studies, cholinergic neurons have been shown to possess extraordinarily plastic axons. This plasticity has not been related comprehensively to mnemonic devises, even though morphological changes in the CNS are prime candidates for the neural engram. In this paper, I propose a hypothesis that relates these two characteristics of cholinergic neurons. This hypothesis is that plastic cholinergic axon terminals induce structural reorganization in their targets during memory storage. Possible intracellular mechanisms are examined, whereby acetylcholine release in the cerebral cortex could cause postsynaptic structural changes. Finally, the characteristics of the overall cholinergic-cholinoceptive cell "engram" are elaborated with particular attention paid to the encoding of the stimulus properties along with the context and meaning of the stimulus.
长期以来，人们已经知道投射到大脑皮层的胆碱能基底前脑神经元在学习和记忆中发挥作用。例如，损伤后的行为研究反复表明这些神经元具有多种与学习相关的作用。除了行为研究外，胆碱能神经元还被证明具有异常可塑性的轴突。尽管中枢神经系统中的形态变化是神经记忆痕迹的主要候选因素，但这种可塑性尚未与记忆机制全面关联。在本文中，我提出了一个将胆碱能神经元的这两个特征联系起来的假说。这个假说就是，可塑性胆碱能轴突终末在记忆存储期间诱导其靶标的结构重组。文中研究了可能的细胞内机制，通过这些机制大脑皮层中的乙酰胆碱释放可导致突触后结构变化。最后，阐述了整体胆碱能 - 胆碱感受性细胞“记忆痕迹”的特征，并特别关注刺激特性的编码以及刺激的背景和意义。
