Laboratory for Systems Neurophysiology, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Laboratory of Neural Information, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan.
Neuron. 2017 Jun 21;94(6):1248-1262.e4. doi: 10.1016/j.neuron.2017.05.024. Epub 2017 Jun 9.
Although the hippocampus is critical to episodic memory, neuronal representations supporting this role, especially relating to nonspatial information, remain elusive. Here, we investigated rate and temporal coding of hippocampal CA1 neurons in rats performing a cue-combination task that requires the integration of sequentially provided sound and odor cues. The majority of CA1 neurons displayed sensory cue-, combination-, or choice-specific (simply, "event"-specific) elevated discharge activities, which were sustained throughout the event period. These event cells underwent transient theta phase precession at event onset, followed by sustained phase locking to the early theta phases. As a result of this unique single neuron behavior, the theta sequences of CA1 cell assemblies of the event sequences had discrete representations. These results help to update the conceptual framework for space encoding toward a more general model of episodic event representations in the hippocampus.
虽然海马体对情景记忆至关重要，但支持这一作用的神经元表示形式，尤其是与非空间信息相关的表示形式，仍然难以捉摸。在这里，我们研究了大鼠在执行需要整合顺序提供的声音和气味线索的线索组合任务时 CA1 神经元的放电率和时间编码。大多数 CA1 神经元表现出感觉线索、组合或选择特异性（简单地说，“事件”特异性）的放电活动升高，这些活动在整个事件期间持续。这些事件细胞在事件开始时经历了短暂的 theta 相位超前，随后对早期 theta 相位持续锁定。由于这种独特的单个神经元行为，事件序列的 CA1 细胞集合的 theta 序列具有离散的表示。这些结果有助于更新空间编码的概念框架，朝着海马体中情景事件表示的更通用模型发展。
