The use of metric and non metric cues in memory: an investigation using reversal learning in appetitive and non-appetitive tasks

在我们的环境中导航并记住物体在该环境中的位置的能力是生存的核心。长期以来，位置的变化一直与海马体细胞活动的变化相关，海马体是已知的大脑区域，对空间学习和导航非常重要。有证据表明，海马细胞的这种活动受环境的距离和角度/方向属性(公制)以及其他属性，如墙壁颜色和照明(非公制)的控制。这些都是相同类型的线索，使我们能够在行为上区分两种环境。我最近的研究使用了反应反转范式(一只大鼠被训练成在T形迷宫上右转，然后被训练成左转，从而大鼠学习在记忆之间产生干扰的竞争反应)，这表明度量属性，特别是方向，是区分两个位置和允许动物做出特定位置反应的最重要特征。本提案中描述的研究将使用大鼠模型来继续调查方向在各种学习任务中的作用，并评估另一种度量属性-距离的作用。这些结果应该会让我们理解我们是如何利用空间信息来防止形成的记忆之间的干扰。更好地了解基本的记忆过程和干扰记忆提取的因素，使我们能够确定当记忆发生故障时，哪些过程受到了损害。为了治疗或减缓由阿尔茨海默病和痴呆症(影响海马体的障碍)等疾病引起的记忆衰竭的进展，我们首先需要知道海马体内的细胞如何受到环境线索的影响，以及这如何在行为变化中表现出来。

The ability to navigate in our environment and remember the location of objects in that environment is central to survival. Changes in location have long been correlated with changes in cell activity in the hippocampus, a brain region known to be important for spatial learning and navigation. Evidence suggests that this hippocampal cell activity is controlled by the distance and angle/direction properties of an environment (metric) and other properties such as wall color and lighting (non-metric). These are the same types of cues that allow us, behaviourally, to distinguish between two environments. My recent work, using a response reversal paradigm (a rat is trained to turn right on a T-maze and then subsequently trained to turn left, thus the rat learns competing responses that produce interference between memories), has shown that metric properties, particularly direction, are the most important feature in distinguishing between two locations and allowing an animal to make a location-specific response. The research described in the present proposal will use a rat model to continue to investigate the role of direction in a variety of learning tasks and also to assess the role of another metric property, distance. These results should allow us to understand how we use spatial information to prevent interference between memories that are formed. A better understanding of basic memory processes and factors that interfere with memory retrieval, allows us to determine what processes are compromised when memory fails. In order to treat or slow the progression of memory failure due to such disorders as Alzheimer's disease and dementia (disorders which affect the hippocampus), we first need to know how cells within the hippocampus are influenced by environmental cues and how this manifests itself in behavioral change.