Institute of Developmental Neurophysiology, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Department of Chemosensation, Institute of Biology II, Rheinisch-Westfalische Technische Hochschule Aachen, Aachen, Germany.
J Physiol. 2020 Dec;598(24):5753-5769. doi: 10.1113/JP280131. Epub 2020 Oct 4.
During early postnatal development, mitral cells show either irregular bursting or non-bursting firing patterns Bursting mitral cells preferentially fire during theta bursts in the neonatal olfactory bulb, being locked to the theta phase Bursting mitral cells preferentially fire during theta bursts in the neonatal lateral entorhinal cortex and are temporally related to both respiration rhythm- and theta phase Bursting mitral cells act as a cellular substrate of the olfactory drive that promotes the oscillatory entrainment of entorhinal networks ABSTRACT: Shortly after birth, the olfactory system provides not only the main source of environmental inputs to blind, deaf, non-whisking and motorically-limited rodents, but also the drive boosting the functional entrainment of limbic circuits. However, the cellular substrate of this early communication remains largely unknown. Here, we combine in vivo and in vitro patch-clamp and extracellular recordings to reveal the contribution of mitral cell (MC) firing to early patterns of network activity in both the neonatal olfactory bulb (OB) and the lateral entorhinal cortex (LEC), the gatekeeper of limbic circuits. We show that MCs predominantly fire either in an irregular bursting or non-bursting pattern during discontinuous theta events in the OB. However, the temporal spike-theta phase coupling is stronger for bursting than non-bursting MCs. In line with the direct OB-to-LEC projections, both bursting and non-bursting discharge augments during co-ordinated patterns of entorhinal activity, albeit with higher magnitude for bursting MCs. For these neurons, temporal coupling to the discontinuous theta events in the LEC is stronger. Thus, bursting MCs might drive the entrainment of the OB-LEC network during neonatal development.
在产后早期发育过程中，僧帽细胞表现出不规则爆发或非爆发式放电模式。爆发式僧帽细胞优先在新生嗅球的θ爆发期间放电，与θ相位锁定。爆发式僧帽细胞优先在新生外侧缰状回皮层的θ爆发期间放电，与呼吸节律和θ相位都有关。爆发式僧帽细胞作为促进缰状回网络的振荡同步的嗅觉驱动的细胞基础。
出生后不久，嗅觉系统不仅为盲、聋、无触须和运动受限的啮齿动物提供了环境输入的主要来源，而且还促进了边缘回路的功能同步。然而，这种早期通讯的细胞基础在很大程度上仍然未知。在这里，我们结合在体和在体膜片钳和细胞外记录，揭示了僧帽细胞（MC）放电对新生嗅球（OB）和外侧缰状回皮层（LEC）中网络活动早期模式的贡献，LEC 是边缘回路的守门员。我们表明，MC 在 OB 中的不连续θ事件期间主要以不规则爆发或非爆发模式放电。然而，爆发式 MC 的时间尖峰-θ相位耦合比非爆发式 MC 更强。与直接的 OB-LEC 投射一致，爆发式和非爆发式放电在缰状回活动的协调模式下都会增加，尽管爆发式 MC 的幅度更高。对于这些神经元，与 LEC 中不连续θ事件的时间耦合更强。因此，爆发式 MC 可能在新生儿发育过程中驱动 OB-LEC 网络的同步。
