Department of Psychology, University of Utah, Salt Lake City, UT 84112, USA.
Neurobiol Learn Mem. 2011 Sep;96(2):361-6. doi: 10.1016/j.nlm.2011.06.011. Epub 2011 Jul 1.
Olfactory working memory and pattern separation for odor information was assessed in male rats using a matching-to-sample for odors paradigm. The odor set consisted of a five aliphatic acids with unbranched carbon chains that varied from two- to six-carbons in length. Each trial consisted of a sample phase followed by a choice phase. During the sample phase, rats would receive one of five different odors. Fifteen seconds later during the choice phase one of the previous odors was presented simultaneously side by side with a different odor that was based on the number of aliphatic acids that varied in the carbon chains from two- to six-carbons in length and rats were allowed to choose between the two odors. The rule to be learned in order to receive a food reward was to always choose the odor that occurred during the study phase. Odor separations of 1, 2, 3 or 4 were selected for each choice phase and represented the carbon chain difference between the study phase odor and the test phase odor. Once an animal reached a criterion of 80-90% correct across all temporal separations based on 40 trials, rats received a control, dorsal hippocampal, or ventral hippocampal lesion and were retested on the task. On postoperative trials, only the ventral hippocampal lesion group was impaired relative to both control and dorsal hippocampal groups groups. There were no effects on odor pattern separation. All groups of rats could discriminate between the odors. The data suggest that the ventral hippocampus, but not dorsal hippocampus, supports working memory for odor information.
采用气味匹配样本范式评估了雄性大鼠的嗅觉工作记忆和模式分离功能。气味集由 5 种具有直链且碳链长度从 2 个碳到 6 个碳不等的脂肪族酸组成。每个试验由样本阶段和选择阶段组成。在样本阶段，大鼠会接收到 5 种不同气味中的一种。15 秒后，在选择阶段，之前的 5 种气味中的一种会与长度从 2 个碳到 6 个碳不等的脂肪族酸的碳链中存在差异的不同气味同时并排呈现，大鼠可以在这两种气味之间进行选择。为了获得食物奖励，需要学习的规则是始终选择在研究阶段出现的气味。选择阶段选择了 1、2、3 或 4 的气味分离，代表研究阶段气味和测试阶段气味之间的碳链差异。一旦动物在基于 40 次试验的所有时间分离上达到 80-90%的正确标准，就会对其进行控制、背侧海马或腹侧海马损伤，并在该任务上进行重新测试。在术后试验中，只有腹侧海马损伤组与对照组和背侧海马组相比受损。对气味模式分离没有影响。所有组的大鼠都可以区分气味。数据表明，腹侧海马而不是背侧海马支持气味信息的工作记忆。
