Department of Biology, Islamic Azad University, Hamedan Branch, Hamedan, Iran.
Physiol Behav. 2011 Mar 28;102(5):542-7. doi: 10.1016/j.physbeh.2011.01.011. Epub 2011 Jan 15.
The ventral tegmental area (VTA) is a neural structure that sends strong efferent projections to the hippocampus. Output from the VTA can affect hippocampal-dependent neural processes that are critical for learning and memory, including long term potentiation and theta activity. However, no study to date has elucidated what role the VTA plays in mediating the different stages of learning and memory. Therefore, the current study was designed to assess how reversible inactivation of the VTA may affect the acquisition, consolidation and retrieval of memory in rats using an inhibitory avoidance (IA) task. In this experiment, rats with chronically implanted cannulae aimed at the VTA were trained on an inhibitory avoidance task. They received intra-VTA infusions of lidocaine or saline immediately before training, after training or before a memory retention test. The results indicate that inactivation of the VTA prior to the first acquisition session increased the number of trials rats required to reach the acquisition criterion. Similarly, inactivation of the VTA after acquisition training decreased the step-through latency and increased the amount of time spent in the dark compartment relative to the saline-treated group. However, inactivation of the VTA immediately prior to the memory retention test failed to alter either step-through latency or the amount of time spent in the dark compartment. Overall, these results suggest the VTA facilitates the acquisition and consolidation of IA learning and memory.
腹侧被盖区（VTA）是一个向海马体发送强烈传出投射的神经结构。VTA 的输出可以影响海马体依赖的神经过程，这些过程对学习和记忆至关重要，包括长时程增强和θ活动。然而，迄今为止没有研究阐明 VTA 在介导学习和记忆的不同阶段中扮演什么角色。因此，目前的研究旨在评估可逆性失活 VTA 如何通过抑制性回避（IA）任务影响大鼠学习和记忆的获取、巩固和检索。在这项实验中，使用慢性植入的导管瞄准 VTA 的大鼠在抑制性回避任务中接受训练。它们在训练前、训练后或记忆保留测试前接受 VTA 内的利多卡因或盐水输注。结果表明，在第一个获取阶段之前失活 VTA 会增加大鼠达到获取标准所需的试验次数。同样，在获得训练后失活 VTA 会降低穿越潜伏期并增加与盐水处理组相比在黑暗隔间中花费的时间量。然而，在记忆保留测试前立即失活 VTA 未能改变穿越潜伏期或在黑暗隔间中花费的时间量。总体而言，这些结果表明 VTA 促进了 IA 学习和记忆的获取和巩固。
