Tonkiss J, Galler J R
Center for Behavioral Development and Mental Retardation, Boston University School of Medicine, MA 02118.
Behav Brain Res. 1990 Nov 15;40(2):95-107. doi: 10.1016/0166-4328(90)90002-v.
The performance of prenatally protein malnourished rats was examined in 2 different tasks of learning and memory beginning at 90 or 160 days of age. In Experiment 1, a rewarded alternation task, run as a spatial working memory procedure on an elevated T-maze, revealed no differences between the formerly malnourished (6/25) and control (25/25) rats when either a minimal or a 20-s inter-trial delay was used. Neither was there a difference when an additional, and conflicting, 'information' run was given to provide a source of proactive interference. In extinction, the 6/25 rats required significantly more sessions to abolish their learned alternation response than the controls. In Experiment 2, an operant equivalent of the T-maze task was applied which allowed greater control over the delay interval and task difficulty. Each trial consisted of a forced information response, for which a randomly selected lever was presented, followed by a free-choice stage, when both levers were presented. The rats were rewarded for pressing the lever not presented at the information stage. The inter-trial interval was always 30 s. When the information response requirement was 10 presses no group differences were found in acquisition of the alternation response or in task performance at delays of 5, 10, 15 or 30 s between information and choice stages. As task difficulty was increased, the performance of the 6/25 rats improved more than that of the 25/25 rats, such that they performed significantly better at the longest delay when the information response requirement was 2 presses. This superior performance of the experimental animals is discussed. No differences in reversal were detected. It was concluded that there is no straight-forward 'hippocampal syndrome' in prenatally malnourished adult rats. Working memory appears largely unaffected, whereas susceptibility to interference and extinction may be modified, depending upon the test parameters employed.
从90日龄或160日龄开始，在两项不同的学习和记忆任务中对产前蛋白质营养不良的大鼠的表现进行了检查。在实验1中，一项奖励交替任务，作为空间工作记忆程序在高架T型迷宫上进行，当使用最短或20秒的试验间隔时，以前营养不良的大鼠（6/25）和对照大鼠（25/25）之间没有差异。当给予额外的、相互矛盾的“信息”运行以提供前摄干扰源时，也没有差异。在消退阶段，6/25的大鼠比对照组需要显著更多的试验次数来消除它们习得的交替反应。在实验2中，应用了T型迷宫任务的操作性等效任务，从而可以更好地控制延迟间隔和任务难度。每次试验包括一个强制信息反应，此时会呈现一个随机选择的杠杆，随后是一个自由选择阶段，此时两个杠杆都会呈现。大鼠因按压在信息阶段未呈现的杠杆而获得奖励。试验间隔始终为30秒。当信息反应要求为10次按压时，在交替反应的习得或信息阶段和选择阶段之间延迟5、10、15或30秒时的任务表现方面，未发现组间差异。随着任务难度的增加，6/25大鼠的表现比25/25大鼠改善得更多，以至于当信息反应要求为2次按压时，它们在最长延迟时的表现显著更好。讨论了实验动物的这种优越表现。未检测到反转差异。得出的结论是，产前营养不良的成年大鼠不存在直接的“海马综合征”。工作记忆似乎基本未受影响，而对干扰和消退的易感性可能会根据所采用的测试参数而改变。
