Kinoshita Seijiro, Yokoyama Chihiro, Masaki Daiki, Yamashita Tatsuhisa, Tsuchida Hideto, Nakatomi Yasuhito, Fukui Kenji
Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
Neurosci Res. 2008 Feb;60(2):213-8. doi: 10.1016/j.neures.2007.10.012. Epub 2007 Nov 9.
When reward reinforcement in a two-choice discrimination task is regularly changed from one stimulus to another immediately after one learning acquisition session, the learning efficiency of a rat increases as if the rat has come to recognize this regularity of reversal. To investigate how the rat medial prefrontal cortex (mPFC) is involved in such improvement, we examined the performance of mPFC-lesioned rats in a serial reversal task of olfactory discrimination. The performance of other mPFC-lesioned rats in a delayed alternation task was also analyzed using the same apparatus to evaluate the contribution of the mPFC to working memory. The mPFC-lesioned rats demonstrated selective difficulty in the second reversal session in the serial reversal task and also showed performance impairment in the delayed alternation task. These results suggest that the rat mPFC mediating working memory is involved in early progress in learning efficiency during experiences of multiple reversals, which may be relevant to cognitive operations in reversal learning beyond a one-time reversal of stimulus response associations.
在双选辨别任务中，当奖励强化在一次学习获取训练后立即从一种刺激定期切换到另一种刺激时，大鼠的学习效率会提高，就好像大鼠已经开始认识到这种反转规律一样。为了研究大鼠内侧前额叶皮质（mPFC）如何参与这种改善，我们在嗅觉辨别序列反转任务中检查了mPFC损伤大鼠的表现。还使用相同的装置分析了其他mPFC损伤大鼠在延迟交替任务中的表现，以评估mPFC对工作记忆的贡献。mPFC损伤大鼠在序列反转任务的第二次反转训练中表现出选择性困难，并且在延迟交替任务中也表现出性能受损。这些结果表明，介导工作记忆的大鼠mPFC参与了多次反转过程中学习效率的早期进展，这可能与刺激反应关联的一次性反转之外的反转学习中的认知操作有关。
