Rosenfeld Cheryl S, Ferguson Sherry A
Biomedical Sciences and Bond Life Sciences Center, University of Missouri;
Division of Neurotoxicology, National Center for Toxicological Research, Food and Drug Administration;
J Vis Exp. 2014 Feb 26(84):e51194. doi: 10.3791/51194.
Spatial learning and memory of laboratory rodents is often assessed via navigational ability in mazes, most popular of which are the water and dry-land (Barnes) mazes. Improved performance over sessions or trials is thought to reflect learning and memory of the escape cage/platform location. Considered less stressful than water mazes, the Barnes maze is a relatively simple design of a circular platform top with several holes equally spaced around the perimeter edge. All but one of the holes are false-bottomed or blind-ending, while one leads to an escape cage. Mildly aversive stimuli (e.g. bright overhead lights) provide motivation to locate the escape cage. Latency to locate the escape cage can be measured during the session; however, additional endpoints typically require video recording. From those video recordings, use of automated tracking software can generate a variety of endpoints that are similar to those produced in water mazes (e.g. distance traveled, velocity/speed, time spent in the correct quadrant, time spent moving/resting, and confirmation of latency). Type of search strategy (i.e. random, serial, or direct) can be categorized as well. Barnes maze construction and testing methodologies can differ for small rodents, such as mice, and large rodents, such as rats. For example, while extra-maze cues are effective for rats, smaller wild rodents may require intra-maze cues with a visual barrier around the maze. Appropriate stimuli must be identified which motivate the rodent to locate the escape cage. Both Barnes and water mazes can be time consuming as 4-7 test trials are typically required to detect improved learning and memory performance (e.g. shorter latencies or path lengths to locate the escape platform or cage) and/or differences between experimental groups. Even so, the Barnes maze is a widely employed behavioral assessment measuring spatial navigational abilities and their potential disruption by genetic, neurobehavioral manipulations, or drug/ toxicant exposure.
实验室啮齿动物的空间学习和记忆通常通过在迷宫中的导航能力来评估，其中最常用的是水迷宫和旱地（巴恩斯）迷宫。在多个阶段或试验中表现的改善被认为反映了对逃生笼/平台位置的学习和记忆。巴恩斯迷宫被认为比水迷宫压力小，它是一个相对简单的设计，圆形平台顶部，周边边缘均匀分布着几个洞。除了一个洞之外，其他所有洞都是假底或盲端的，而有一个洞通向逃生笼。轻度厌恶刺激（如头顶明亮的灯光）促使动物找到逃生笼。在试验过程中可以测量找到逃生笼的潜伏期；然而，其他终点指标通常需要视频记录。从这些视频记录中，使用自动跟踪软件可以生成各种终点指标，这些指标与水迷宫中产生的指标类似（例如行进距离、速度、在正确象限花费的时间、移动/休息花费的时间以及潜伏期确认）。搜索策略的类型（即随机、序列或直接）也可以分类。巴恩斯迷宫的构建和测试方法对于小鼠等小型啮齿动物和大鼠等大型啮齿动物可能有所不同。例如，虽然迷宫外部线索对大鼠有效，但较小的野生啮齿动物可能需要迷宫内部线索以及迷宫周围的视觉屏障。必须确定适当的刺激，以促使啮齿动物找到逃生笼。巴恩斯迷宫和水迷宫都可能很耗时，因为通常需要4 - 7次测试试验才能检测到学习和记忆表现的改善（例如找到逃生平台或笼子的潜伏期或路径长度缩短）和/或实验组之间的差异。即便如此，巴恩斯迷宫仍是一种广泛应用的行为评估方法，用于测量空间导航能力以及它们可能因基因、神经行为操作或药物/毒物暴露而受到的干扰。
