The hippocampus (HPC) and the lateral prefrontal cortex (LPFC) are two cortical areas of the primate brain deemed essential to cognition. Here, we hypothesized that the codes mediating neuronal communication in the HPC and LPFC microcircuits have distinctively evolved to serve plasticity and memory function at different spatiotemporal scales. We used a virtual reality task in which animals selected one of the two targets in the arms of the maze, according to a learned context-color rule. Our results show that during associative learning, HPC principal cells concentrate spikes in bursts, enabling temporal summation and fast synaptic plasticity in small populations of neurons and ultimately facilitating rapid encoding of associative memories. On the other hand, layer II/III LPFC pyramidal cells fire spikes more sparsely distributed over time. The latter would facilitate broadcasting of signals loaded in short-term memory across neuronal populations without necessarily triggering fast synaptic plasticity.

海马体 (HPC) 和外侧前额叶皮层 (LPFC) 是灵长类大脑的两个被认为对认知至关重要的皮质区域。在这里，我们假设在 HPC 和 LPFC 微电路中调节神经元通信的代码已经明显进化为在不同的时空尺度上提供可塑性和记忆功能。我们使用了一项虚拟现实任务，其中动物根据学习的上下文颜色规则选择迷宫手臂中的两个目标之一。我们的研究结果表明，在联想学习期间，HPC 主细胞集中爆发尖峰，在少量神经元中实现时间求和和快速突触可塑性，并最终促进联想记忆的快速编码。另一方面，II/III 层 LPFC 锥体细胞发射的尖峰随着时间的推移分布更稀疏。