Reading P J, Dunnett S B, Robbins T W
Department of Experimental Psychology, University of Cambridge, U.K.
Behav Brain Res. 1991 Nov 26;45(2):147-61. doi: 10.1016/s0166-4328(05)80080-4.
The effects of discrete bilateral ibotenic acid lesions to 3 areas of striatum were examined on a conditional visual discrimination task involving temporal frequency (SLOW vs FAST flashes) that had previously been shown to be sensitive to the effects of dorsal striatal dopamine depletion. Two of the groups, namely, those with nucleus accumbens (ACC) and lateral caudate-putamen (LCP) lesions, were very disrupted in the acquisition of the task. The nature of the respective impairments of the 2 groups was dissociable, however. The performance of the ACC group could be improved either by manipulations of stimulus duration or inter-stimulus interval, implying an attentional deficit. In contrast, the rats with lesions of the LCP were not significantly improved by any of the behavioural challenges. Their performance was characterised by a bias to respond to the SLOW discriminandum. Under conditions of non-reward, the LCP group extinguished their responding at a similar rate to control rats whereas the ACC group were very much more persistent. Lesions of the medial caudate-putamen failed to affect any index of performance significantly. These data suggest that the LCP is necessary for the acquisition of arbitrary stimulus-response rules and that damage to an equivalent area in humans, such as in Huntington's disease, may explain deficits of procedural memory. The second part of the experiment investigated the effects of ACC lesions on established performance of the schedule. The lesioned group behaved identically to the ACC group that had been lesioned prior to acquisition, both in terms of accuracy and degree of persistence in extinction, further implying the role of attentional factors and inflexibility in the lesion-induced deficit.
研究了对纹状体3个区域进行离散双侧鹅膏蕈氨酸损伤对一项涉及时间频率（慢闪与快闪）的条件性视觉辨别任务的影响，该任务先前已被证明对背侧纹状体多巴胺耗竭的影响敏感。其中两组，即伏隔核（ACC）和外侧尾状核-壳核（LCP）损伤组，在任务习得过程中受到严重干扰。然而，这两组各自损伤的性质是可分离的。ACC组的表现可以通过操纵刺激持续时间或刺激间隔来改善，这意味着存在注意力缺陷。相比之下，LCP损伤的大鼠在任何行为挑战下都没有明显改善。它们的表现特点是对慢辨别刺激有反应偏向。在无奖励条件下，LCP组的反应消退速度与对照组大鼠相似，而ACC组则持续得多。内侧尾状核-壳核损伤未能显著影响任何性能指标。这些数据表明，LCP对于习得任意刺激-反应规则是必要的，并且人类中类似区域的损伤，如在亨廷顿病中，可能解释程序性记忆缺陷。实验的第二部分研究了ACC损伤对既定实验程序表现的影响。损伤组在准确性和消退时的持续程度方面，与在习得前就已损伤的ACC组表现相同，这进一步暗示了注意力因素和僵化在损伤诱导缺陷中的作用。
