Devan Bryan D, Tobin Elizabeth L, Dunn Emily N, Magalis Christopher
Laboratory of Comparative Neuropsychology, Psychology Department, Towson University, Towson, MD 21252, USA.
Laboratory of Comparative Neuropsychology, Psychology Department, Towson University, Towson, MD 21252, USA.
Behav Processes. 2016 Nov;132:34-41. doi: 10.1016/j.beproc.2016.09.009. Epub 2016 Sep 28.
This study investigated sex differences on the competitive place version of the Morris water maze task to determine whether potential strategy differences would emerge during any phase of the study but in particular on the competitive place phase. Previous findings indicate that this version of the task is highly sensitive to measures that disrupt NMDA-dependent synaptic plasticity within the hippocampus during memory consolidation (McDonald et al., 2005). The present findings revealed significant sex differences during all phases of the study, including Phase I with standard place training to located a hidden platform/goal, Phase II mass training to a new place with the platform/goal relocated to the diagonally opposite quadrant and Phase III, competitive place probe test with the platform removed to measure spatial behaviour directed at either location. The findings showed no sex difference in escape latency and other standard performance measures during the first two phases, initial place acquisition and mass training to a new location. A very subtle male advantage in visiting both Old and New place locations during the third phase place competition test was observed, however, in the time spent swimming in the periphery of the pool, the pool wall (Zone C - outer third radial distance) was increased for females during all phases of the study, suggesting a general effect may have influenced place location search behaviour of the females. Increased peripheral pool time may represent a female preference for approaching the wall, a local cue. Alternatively, the possibility that increased peripheral swimming/thigmotaxis may represent hormonal influences interacting with strategic preferences were discussed, though no definitive conclusions about sex differences in cognitive-spatial performance or memory consolidation were inferred from the present findings. The findings suggest that mixed results reported in the literature by others may be due in part to an interaction with a persistent peripheral pool swimming response demonstrated in female rats.
本研究调查了在莫里斯水迷宫任务的竞争位置版本中性别差异，以确定在研究的任何阶段是否会出现潜在的策略差异，特别是在竞争位置阶段。先前的研究结果表明，该任务版本对在记忆巩固过程中破坏海马体内NMDA依赖性突触可塑性的措施高度敏感（麦克唐纳等人，2005年）。目前的研究结果显示，在研究的所有阶段都存在显著的性别差异，包括第一阶段，即通过标准位置训练来定位隐藏平台/目标；第二阶段，即大量训练到一个新位置，平台/目标重新安置到对角象限；以及第三阶段，即竞争位置探测测试，移除平台以测量针对任一位置的空间行为。研究结果表明，在前两个阶段，即初始位置获取和大量训练到新位置期间，逃避潜伏期和其他标准性能指标没有性别差异。然而，在第三阶段的位置竞争测试中，观察到雄性在访问旧位置和新位置时具有非常细微的优势。在研究的所有阶段，雌性在池壁（C区 - 外三分之一径向距离）附近游泳的时间增加，这表明可能有一个普遍效应影响了雌性的位置搜索行为。增加的池周时间可能代表雌性对靠近池壁这一局部线索的偏好。另外，也讨论了增加的外周游泳/趋触性可能代表激素影响与策略偏好相互作用的可能性，尽管从目前的研究结果中没有推断出关于认知空间性能或记忆巩固中性别差异的明确结论。研究结果表明，其他人在文献中报道的混合结果可能部分归因于与雌性大鼠中持续的外周池游泳反应的相互作用。
