Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, Genova, Italy.
Università degli Studi di Genova, Via Balbi, 5, 16126, Genova, Italy.
Nat Commun. 2019 Mar 13;10(1):1195. doi: 10.1038/s41467-019-09156-3.
The development of functional synapses is a sequential process preserved across many brain areas. Here, we show that glutamatergic postsynaptic currents anticipated GABAergic currents in Layer II/III of the rat neocortex, in contrast to the pattern described for other brain areas. The frequencies of both glutamatergic and GABAergic currents increased abruptly at the beginning of the second postnatal week, supported by a serotonin upsurge. Integrative behaviors arose on postnatal day (P)9, while most motor and sensory behaviors, which are fundamental for pup survival, were already in place at approximately P7. A reduction in serotonin reuptake accelerated the development of functional synapses and integrative huddling behavior, while sparing motor and sensory function development. A decrease in synaptic transmission in Layer II/III induced by a chemogenetic approach only inhibited huddling. Thus, precise developmental sequences mediate early, socially directed behaviors for which neurotransmission and its modulation in supragranular cortical layers play key roles.
功能突触的发育是一个在许多脑区中都被保留的连续过程。在这里，我们发现在大鼠新皮层的 II/III 层中，谷氨酸能突触后电流先于 GABA 能突触后电流，这与其他脑区所描述的模式相反。谷氨酸能和 GABA 能电流的频率都在出生后第二周开始时突然增加，这得到了 5-羟色胺激增的支持。整合行为出现在出生后第 9 天（P9），而大多数运动和感觉行为，这些行为对于幼崽的生存至关重要，已经在大约 P7 时形成。通过减少 5-羟色胺再摄取来加速功能突触和整合式抱团行为的发展，同时不影响运动和感觉功能的发展。通过化学遗传方法减少 II/III 层中的突触传递仅抑制了抱团。因此，精确的发育顺序介导了早期的、面向社会的行为，其中神经递质传递及其在颗粒上层中的调制起着关键作用。
