Morrell F, Hoeppner T J, de Toledo-Morrell L
Exp Neurol. 1983 Apr;80(1):111-46. doi: 10.1016/0014-4886(83)90010-9.
These experiments examine the interrelationships between the activity of adjacent neurons during learning. Does learning depend on coherent behavior in a population of neurons or does it depend on particular neurons engaging in a particular activity at specific times? A second purpose was to examine specificity in response modification as a function of reinforcement contingency. Cells from visual association cortex of locally anesthetized, paralyzed cats and rabbits were studied with extracellular microelectrodes capable of recording single and multiunit activity, as well as local field potentials. Multiunit records were fractionated by amplitude "windows" discrimination. Pavlovian discriminative conditioning procedures were used to evaluate selective plasticity. Cells that were activated by at least two different visual stimuli were selected. Only one of the effective stimuli was paired with foot-shock (reinforcement). Of the 180 cells or cell clusters studied, 27% exhibited conditioned modification to the reinforced stimulus (CS+) and 19% changed their response pattern to the unreinforced stimulus (CS-). None of the well isolated cells showed conditioning to both CS+ and CS-. Thus, cellular plasticity was specific to reinforcement contingency. These results provide a first demonstration of reinforcement-dependent functional distinctiveness at the neuronal level. Some cells showed no alteration of response pattern despite a most prolonged conditioning procedure. Neighboring cells, responsive to the same stimuli, revealed increases or decreases in firing rate, selective changes in the latency or amplitude of single response peaks, or the appearance of one or more new peaks as a function of conditioning. Rarely did adjacent cells show the same type of alteration when alteration occurred; there was no general tendency toward coherent firing patterns as conditioning proceeded.
这些实验研究了学习过程中相邻神经元活动之间的相互关系。学习是依赖于神经元群体中的连贯行为，还是依赖于特定神经元在特定时间进行特定活动？第二个目的是研究作为强化偶然性函数的反应调节特异性。使用细胞外微电极对局部麻醉、瘫痪的猫和兔子的视觉联合皮层细胞进行研究，该电极能够记录单单位和多单位活动以及局部场电位。多单位记录通过幅度“窗口”鉴别进行分离。采用经典条件性辨别程序来评估选择性可塑性。选择至少由两种不同视觉刺激激活的细胞。只有一种有效刺激与足部电击（强化）配对。在研究的180个细胞或细胞簇中，27%对强化刺激（CS+）表现出条件性改变，19%对非强化刺激（CS-）改变了其反应模式。没有一个分离良好的细胞对CS+和CS-都表现出条件作用。因此，细胞可塑性对强化偶然性具有特异性。这些结果首次证明了在神经元水平上强化依赖的功能特异性。尽管进行了最长时间的条件作用程序，一些细胞的反应模式没有改变。对相同刺激有反应的相邻细胞，根据条件作用，其放电率增加或减少，单个反应峰值的潜伏期或幅度有选择性变化，或者出现一个或多个新的峰值。当发生改变时，相邻细胞很少表现出相同类型的改变；随着条件作用的进行，没有出现一致放电模式的普遍趋势。
