Spontaneous Synchronous Network Activity (SSA) is a hallmark of neurodevelopment found in numerous central nervous system structures, including neocortex. SSA occurs during restricted developmental time‐windows, commonly referred to as critical periods in sensory neocortex. Although part of the neocortex, the critical period for SSA in the medial prefrontal cortex (mPFC) and the underlying mechanisms for generation and propagation are unknown. Using Ca²⁺ imaging and whole‐cell patch‐clamp in an acute mPFC slice mouse model, the development of spontaneous activity and SSA was investigated at cellular and network levels during the two first postnatal weeks. The data revealed that developing mPFC neuronal networks are spontaneously active and exhibit SSA in the first two postnatal weeks, with peak synchronous activity at postnatal days (P)8–9. Networks remain active but are desynchronized by the end of this 2‐week period. SSA was driven by excitatory ionotropic glutamatergic transmission with a small contribution of excitatory GABAergic transmission at early time points. The neurohormone oxytocin desynchronized SSA in the first postnatal week only without affecting concurrent spontaneous activity. By the end of the second postnatal week, inhibiting GABA_A receptors restored SSA. These findings point to the emergence of GABA_A receptor‐mediated inhibition as a major factor in the termination of SSA in mouse mPFC.

中文翻译：

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小鼠 mPFC 新生儿发育中的自发同步网络活动

自发同步网络活动 (SSA) 是在包括新皮质在内的众多中枢神经系统结构中发现的神经发育的标志。SSA 发生在受限制的发育时间窗内，通常称为感觉新皮层的关键时期。虽然是新皮层的一部分，但内侧前额叶皮层 (mPFC) 中 SSA 的关键期以及产生和传播的潜在机制尚不清楚。使用 Ca ²⁺在急性 mPFC 切片小鼠模型中进行成像和全细胞膜片钳，在出生后头两个星期在细胞和网络水平上研究自发活动和 SSA 的发展。数据显示，发育中的 mPFC 神经元网络自发活跃并在出生后的前两周表现出 SSA，在出生后几天同步活动达到峰值 (P)8-9。网络保持活跃，但在这 2 周结束时会失去同步。SSA 由兴奋性离子型谷氨酸能传输驱动，在早期时间点兴奋性 GABA 能传输的贡献很小。神经激素催产素仅在出生后第一周使 SSA 不同步，而不会影响同时发生的自发活动。到出生后第二周结束时，抑制 GABA _A受体恢复SSA。这些发现表明 GABA _A受体介导的抑制是小鼠 mPFC 中 SSA 终止的主要因素。