Graduate Program in Neuroscience, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA.
Department of Neuroscience, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA.
Hippocampus. 2020 Nov;30(11):1194-1208. doi: 10.1002/hipo.23250. Epub 2020 Aug 18.
Deliberation is thought to involve the internal simulation of the outcomes of candidate actions, the valuation of those outcomes, and the selection of the actions with the highest expected value. While it is known that deliberation involves prefrontal cortical areas, specifically the dorsomedial prefrontal cortex (dmPFC), as well as the hippocampus (HPC) and other brain regions, how these areas process prospective information and select actions is not well understood. We recorded simultaneously from ensembles in dmPFC and CA1 of dorsal HPC in rats during performance of a spatial contingency switching task, and examined the relationships between spatial and reward encoding in these two areas during deliberation at the choice point. We found that CA1 and dmPFC represented either goal locations or the current position simultaneously, but that when goal locations were encoded, HPC and dmPFC did not always represent the same goal location. Ensemble activity in dmPFC predicted when HPC would represent goal locations, but on a broad timescale on the order of seconds. Also, reward encoding in dmPFC increased during hippocampal theta cycles where CA1 ensembles represented the goal location. These results suggest that dmPFC and HPC share prospective information during deliberation, that dmPFC may influence whether HPC represents prospective information, and that information recalled about goal locations by HPC may be integrated into dmPFC reward representations on fast timescales.
思考被认为涉及对候选行动结果的内部模拟、对这些结果的评估,以及对具有最高预期价值的行动的选择。虽然人们知道思考涉及前额叶皮质区域,特别是背内侧前额叶皮质(dmPFC),以及海马体(HPC)和其他脑区,但这些区域如何处理预期信息并选择行动尚不清楚。我们在大鼠执行空间关联切换任务期间,同时从 dmPFC 和背侧 HPC 的 CA1 中记录了集合,并且在选择点的思考过程中检查了这两个区域中空间和奖励编码之间的关系。我们发现 CA1 和 dmPFC 可以同时表示目标位置或当前位置,但当表示目标位置时,HPC 和 dmPFC 并不总是表示相同的目标位置。dmPFC 的集合活动预测了 HPC 将何时表示目标位置,但在几秒钟的宽时间尺度上。此外,dmPFC 中的奖励编码在 CA1 集合表示目标位置的海马体 theta 循环期间增加。这些结果表明,dmPFC 和 HPC 在思考过程中共享预期信息,dmPFC 可能影响 HPC 是否表示预期信息,并且 HPC 回忆的关于目标位置的信息可能在快速时间尺度上整合到 dmPFC 的奖励表示中。