Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada.
Department of Psychology, Trent University, Peterborough, ON K9L 0G2, Canada.
J Integr Neurosci. 2024 Nov 18;23(11):205. doi: 10.31083/j.jin2311205.
The goal of these experiments was to determine which learning and memory system(s) were necessary for the retention of visual discriminations and subsequent acquisition of a second problem. The dorsal striatum should be involved in the acquisition and expression of this task based on previous work implicating this region in instrumental learning and memory processes. The perirhinal cortex has been implicated in learning and memory processes associated with visual information like objects, and pictures and may also play a role in the acquisition and/or retention of visual discriminations. As there is no clear spatial/relational component to the task, the hippocampus should not be involved.
Rats were trained on a two-choice visual discrimination task to criterion performance after which they received lesions to portions of the dorsal striatum (dorso-medial or dorso-lateral striatum) and medial temporal lobe (perirhinal cortex or hippocampus). After surgical recovery, the rats were tested for retention of the original discrimination, followed by training on a second problem on the same task.
The results showed that dorsal medial striatal lesions produced a retrograde deficit on picture discrimination, but dorsal lateral striatum lesions did not. Neither dorsal striatal lesion produced a deficit on acquisition of a second problem. Perirhinal cortex did not seem to make an essential contribution to the retention of the original discrimination or acquisition of the second problem. Surprisingly, subjects with hippocampal damage were severely impaired but eventually re-learned the discrimination. Damage to the hippocampus had no impact on acquisition of a second problem.
Taken together, the results of the present experiments show that the dorsomedial striatum and the hippocampus may support performance on this instrumental task if intact during acquisition but is not required for acquisition of a new problem. The implications of this pattern of results for our understanding of the organization of learning and memory in mammals is discussed.
这些实验的目的是确定哪些学习和记忆系统对于保留视觉辨别和随后获得第二个问题是必要的。基于先前的工作表明该区域参与了工具性学习和记忆过程，背侧纹状体应该参与到该任务的获取和表达中。在与视觉信息（如物体、图片）相关的学习和记忆过程中，旁海马回被牵涉其中，它可能也在获取和/或保留视觉辨别中发挥作用。由于任务没有明确的空间/关系成分，海马体不应参与其中。
大鼠在进行了两个选择的视觉辨别任务训练后，达到标准表现，然后对其背侧纹状体（背侧内侧或背侧外侧纹状体）和内侧颞叶（旁海马回或海马体）的部分进行了损伤。在手术恢复后，对大鼠进行了原始辨别任务的保留测试，然后在同一任务上进行了第二个问题的训练。
结果表明，背侧内侧纹状体损伤导致图片辨别出现逆行性缺陷，但背侧外侧纹状体损伤没有。这两种背侧纹状体损伤都没有导致第二个问题的获取出现缺陷。旁海马回似乎对原始辨别任务的保留或第二个问题的获取没有做出必要的贡献。令人惊讶的是，海马体受损的动物严重受损，但最终重新学习了辨别。海马体损伤对第二个问题的获取没有影响。
综上所述，本实验的结果表明，在获取过程中如果背侧纹状体内侧和海马体完好无损，它们可能支持对该工具性任务的表现，但对于获取新问题则不是必需的。对这种结果模式的讨论，有助于我们理解哺乳动物学习和记忆的组织。
