Cerebellum and Classical Conditioning of Motor Responses
Cerebellum and Classical Conditioning of Motor Responses
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小脑和运动反应的经典条件反射
DOI：
10.1111/j.1749-6632.1991.tb25933.x
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发表时间：
1991
影响因子：
5.2
通讯作者：
C. Yeo
中科院分区：
文献类型：
--
作者：
C. Yeo
在无法形成新记忆的严重健忘症患者身上，学习和记忆的重要性最为明显。边缘结构，特别是海马体的损伤会产生健忘症状，但这些损伤会使一些记忆系统完好无损。由于运动技能是可以获得和保留的，不同的学习形式必须依赖于大脑中的不同回路。为了简化学习的神经分析，巴甫洛夫引入了反射条件反射程序，提供与其他背景行为隔离的严密控制的学习反应。在几次这样的配对之后，他在给他的狗上食物之前立即按下了铃，当铃声响起时，狗开始流口水。“用巴甫洛夫的术语来说，食物是无条件的刺激(美国)，因为它无条件地引起流口水，而铃声是条件刺激(CS)，因为它只有在与食物搭配时才会引起流口水。对食物的反射反应是无条件反射(UR)，而对CS的新的习得反应是条件反应(CR)。这种基本的、延迟的条件反射设计(之所以这样命名，是因为CS和US的起点之间有一个很短的延迟)是巴甫洛夫发展的几个条件反射程序中最简单的一个，但我们对联想学习过程的大部分理解都源于它。巴甫洛夫从唾液反应开始他的条件反射研究，但这个程序被扩展到骨骼肌反射，如肢体屈曲。条件性运动反应现在被广泛应用于学习机制的分析。然而，在人类健忘症的许多情况下，这种条件作用很小。一名患有科萨科夫综合征并表现出严重健忘症的患者被证明具有正常的眨眼条件反射水平，尽管他不记得每天接触到的实验程序。“这是否应该导致我们放弃巴甫洛夫条件反射作为学习机制研究的模型？”大概不会吧。越来越多的证据来自对动物、正常人和健忘症患者的研究，尽管学习和记忆可能有不同的形式，这些可能关键取决于不同的大脑区域，但它们背后的细胞机制可能相当相似。巴甫洛夫精确定义的行为变化单位用于分析学习的神经机制的优势仍然没有受到挑战。
Nowhere is the crucial importance of learning and memory more evident than in severely amnesic patients who are unable to form new memories. Damage to limbic structures, particularly hippocampus, produces amnesic symptoms, but these lesions leave some memory systems intact. Since motor skills can be acquired and retained, different forms of learning must depend upon different circuits within the brain. In order to simplify the neural analysis of learning, Pavlov introduced reflex conditioning procedures that provide a closely controlled learned response isolated from other, background behaviors. He rang a bell immediately before presenting food to his dogs after several such pairings, they began to salivate as the bell was sounded and before presentation of the food.'Using Pavlov's terminology, the food is an unconditioned stimulus (US) because it unconditionally elicits salivation and the bell is a conditioned stimulus (CS) because it elicits salivation only conditionally upon it having been paired with food. The reflex response to food is the unconditioned reflex (UR) and the new, learned response to the CS is the conditioned response (CR). This basic, delay conditioning design (so named because there is a short delay between the onsets of the CS and US) is the simplest of several conditioning procedures that Pavlov developed, but much of our understanding of associative learning processes derives from it.Pavlov began his conditioning studies with the salivation response, but the procedure was extended to skeletal muscle reflexes such as limb flexion. Conditioned motor responses are now widely used in the analysis of learning mechanisms. And yet such conditioning is very little affected in many instances of human amnesia. A patient with Korsakoffs syndrome and exhibiting severe amnesia was shown to have normal levels of eyeblink conditioning even though he had no recollection of the experimental procedures to which he was exposed daily.'Should this lead us to abandon Pavlovian conditioning as a model for our study of learning mechanisms? Probably not. Evidence is increasing from studies in animals and in normal and amnesic humans that, though there may be different forms of learning and memory and these may depend critically on different brain areas, the cellular mechanisms that underlie them may be rather similar. The advantage of Pavlov's precisely defined unit of behavioral change for analysis of the neural mechanisms of learning remains unchallenged.