Li L, Shao J
Department of Psychology, Peking University, Beijing, People's Republic of China.
Physiol Behav. 1998 Nov 15;65(2):371-9. doi: 10.1016/s0031-9384(98)00216-9.
Previous studies have shown that extensive damage to the medial prefrontal cortex (mPFC) of rats causes reversal learning deficits. The mPFC of rats, however, consists of several subareas that are different from each other in both cytoarchitecture and neural connectivity, suggesting a functional dissociation among the mPFC subareas. In the present study, selective lesions of the mPFC of rats were made with a specially designed microknife whose intracranial placement could be controlled stereotaxically. Restricted lesions were made to each of the 3 parts of the mPFC: the anterior cingulate area (AC) (including the medial precentral area, PrCm), the prelimbic area (PL), and the infralimbic area (IL). One week after surgery, rats were trained in an aversively motivated visual discrimination task in a novel rotating T-maze. After reaching the acquisition criterion, rats were trained in a reversal task in the same maze. No difference was found in acquisition between control and mPFC lesioned rats. However, lesions of either the PL or the IL produced a marked deficit in the reversal task. This behavioral deficit was not found in rats with lesions of the AC. The results indicate that the mPFC of rats is not essential for discrimination learning, but that each of the 2 ventral subareas of the mPFC, PL, and IL, plays a critical role in reversal learning.
以往的研究表明，大鼠内侧前额叶皮质（mPFC）受到广泛损伤会导致逆向学习缺陷。然而，大鼠的mPFC由几个不同的亚区域组成，这些亚区域在细胞结构和神经连接方面都彼此不同，这表明mPFC亚区域之间存在功能分离。在本研究中，使用专门设计的微型刀对大鼠的mPFC进行选择性损伤，微型刀在颅内的放置可通过立体定位进行控制。对mPFC的三个部分中的每一个进行了局限性损伤：前扣带区（AC）（包括中央前内侧区，PrCm）、前边缘区（PL）和边缘下区（IL）。手术后一周，在一个新颖的旋转T迷宫中对大鼠进行厌恶动机视觉辨别任务训练。达到习得标准后，在同一迷宫中对大鼠进行逆向任务训练。在对照组和mPFC损伤大鼠之间，未发现习得方面的差异。然而，PL或IL损伤的大鼠在逆向任务中出现了明显的缺陷。AC损伤的大鼠未出现这种行为缺陷。结果表明，大鼠的mPFC对辨别学习并非必不可少，但mPFC的两个腹侧亚区域PL和IL中的每一个在逆向学习中都起着关键作用。
