实验方案
线索平台与隐藏平台训练
先确认它们看得见、会游泳,再要求它们记住。
如果动物找不到隐藏平台,是它健忘、近视、体弱,还是只是焦虑?线索(可见)平台阶段可以帮你分辨,因为它需要视力、游泳能力和动机,但不需要空间地图。Richard Anderson博士1998年的笔记描述了完整的流程,从插旗平台到隐藏平台,再到探测试验和反转:
更多莫里斯水迷宫内容
12/98. Copyright (C) 1998 RA & HVS.
感谢Dr Richard Anderson提供。由HVS编辑。
We can examine reference learning and memory in the Morris water maze. Initially the mice are trained to locate a cued, flagged platform. During this phase of the study both the cued platform position and the starting position of the mouse are randomly varied to avoid habituating the mouse to a particular area of the pool. Following this sensory motor test the cued platform is switched with a submerged platform the position of which is fixed for each mouse. As the mouse learns its position the path lengths and latencies to locate the platform are reduced. Following the final placed session, the platform is removed and the swim-pattern of the mice is tracked for one minute. We then compare the time the mouse spends swimming in the former platform quadrant with the time in the other three. This gives a measure of memory and also allows us to see if the mice are using different strategies to find the platform. For example, instead of using the distal cues, some mice learn to swim at a fixed distance from the edge of the pool until they find the platform. An additional HVS measure one can take includes the number of platform position crossings. Again if the mouse shows good evidence of spatial memory the mouse will exhibit a significantly increased number of former platform position crossings in comparison with the other three. A further advantage of this model is that by reversing the submerged platform position, it allows us to examine flexibility of learning, i.e. how easy is it for the mouse to let go of one learned behavior and acquire the new task. Inflexibility of learning is an early feature of AD dementia.
原文(英文):Dr Richard Anderson,1998年12月,HVS编辑。Copyright (C) 1998 RA & HVS.按原样转载,未作改动。Copyright Richard Baker© 2013. All Rights Reserved.
常见问题
为什么要进行线索(可见平台)试次?
线索试次检查每只动物是否看得清、游得好,并且有逃生动机。如果它在线索试次中失败,那么隐藏平台成绩差可能并不意味着记忆差。当地伦理委员会、许可条件和兽医的意见始终优先。
更多细节
进行线索试次时要拉上窗帘,并随机设置起点和目标位置 [Vorhees & Williams 2024]。在一项涉及13个品系的研究中,视力解释了品系差异的很大一部分 [Brown & Wong 2007]。
深入了解
小鼠通常接受1天的可见平台训练;大鼠在测试结束时接受2天的线索试次 [Vorhees & Williams 2024]。
关于线索试次和隐藏试次所用的设备,请参阅常规逃生平台。