Stefani Mark R, Moghaddam Bita
Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Behav Neurosci. 2005 Apr;119(2):420-8. doi: 10.1037/0735-7044.119.2.420.
The authors examined discrimination rule learning and extradimensional set-shifting ability in rats given systemic or intracranial injections of the N-methyl-D-aspartate (NMDA) receptor antagonist MK801. Pretraining systemic injections of MK801 impaired both the acquisition of the initial discrimination rule (Set 1) and the shift to the 2nd rule (Set 2). Pretraining intramedial prefrontal cortical (mPFC) administration of MK801 did not impair Set 1 acquisition. Intra-mPFC injection of MK801 was previously found to impair Set 2 acquisition. Impaired Set 2 performance was due to increased cognitive perseveration. The data suggest that discrimination learning in naive subjects requires NMDA receptors outside the mPFC, whereas NMDA receptors within the mPFC are selectively involved in the modification of previous knowledge and/or the inhibition of previously learned responses.
作者研究了给大鼠全身或颅内注射N-甲基-D-天冬氨酸（NMDA）受体拮抗剂MK801后，其辨别规则学习和维度外集合转换能力。训练前全身注射MK801会损害最初辨别规则（集合1）的习得以及向第二条规则（集合2）的转换。训练前内侧前额叶皮质（mPFC）给予MK801不会损害集合1的习得。先前发现mPFC内注射MK801会损害集合2的习得。集合2表现受损是由于认知固着增加。数据表明，未接触过的受试者的辨别学习需要mPFC以外的NMDA受体，而mPFC内的NMDA受体选择性地参与先前知识的修正和/或对先前习得反应的抑制。
