Effects of selective thalamic and prelimbic cortex lesions on two types of visual discrimination and reversal learning
Effects of selective thalamic and prelimbic cortex lesions on two types of visual discrimination and reversal learning
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DOI：
10.1046/j.0953-816x.2001.01607.x
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发表时间：
2001-09-01
影响因子：
3.4
通讯作者：
Muir, JL
中科院分区：
文献类型：
--
作者：
Chudasama, Y;Bussey, TJ;Muir, JL
兴奋性毒性病变的丘脑，丘脑前核和前边缘皮层的内侧背核的影响进行了检查的歧视和逆转学习的两个测试。在实验1A（视觉辨别和反转）中，要求大鼠辨别两种刺激，并对与奖励相关的刺激（S+刺激）做出反应。病变对该任务的获得没有影响。然而，当刺激-奖励偶然事件被逆转时，丘脑背内侧核病变的动物比对照组动物或其他病变组动物犯了更多的错误。在实验1 B（条件性辨别）中，要求动物学习“如果刺激A则向左，如果刺激B则向右”的规则。在本实验中没有观察到损伤对采集的主要影响。为了测试在实验1A中获得的逆转效应的一般性，具有相同病变的第二组动物在手术后立即进行视觉空间条件任务的采集，然后进行条件规则的逆转（实验2）。与实验1B一样，在任务获取过程中没有观察到损伤组的主效应。然而，病变的丘脑背内侧核导致轻微的损害，根据所需的会话数量达到标准的性能的任务时，反应规则被逆转。本研究的结果提供了证据的作用，在新的学习，特别是当刺激奖励的偶然性被逆转的丘脑中背内侧核。此外，。他们表明，该丘脑核的功能可以与前丘脑和前边缘皮质的功能分离。
The effects of excitotoxic lesions of the mediodorsal nucleus of the thalamus, the anterior thalamic nuclei and of the prelimbic cortex were examined on two tests of discrimination and reversal learning. In experiment 1A (visual discrimination and reversal), rats were required to discriminate two stimuli, and respond to the stimulus associated with reward (the S+ stimulus). There was no effect of lesion on acquisition of this task. However, when stimulus-reward contingencies were reversed, animals with lesions of the mediodorsal nucleus of the thalamus made significantly more errors than control animals or animals of other lesion groups. In experiment 1B (conditional discrimination), animals were required to learn a rule of the, type 'If stimulus A then go left, if stimulus B then go right'. No main effect of lesion on acquisition was observed in this experiment. To test the generality of the reversal effect obtained in experiment 1A, a second cohort of animals with the same lesions was, tested on acquisition of the visuospatial conditional task immediately postsurgery, followed by the reversal of the conditional rule (experiment 2). As in experiment 1B, no main effect of lesion group was observed during acquisition of the task. However, lesions of the mediodorsal nucleus of the thalamus resulted in a mild impairment according to number of sessions required to attain criterion performance of the task when the response rule was reversed. The results of the present study provide evidence for a role for the mediodorsal nucleus of the thalamus in new learning, particularly when stimulus-reward contingencies are reversed. Furthermore,. they show that the functions of this thalamic nucleus can be dissociated from those of the anterior thalamus and the prelimbic cortex.