GABAergic interneurons form transient layer-specific circuits in early postnatal neocortex

Anastasiades, Paul G. and Marques-Smith, Andre and Lyngholm, Daniel and Lickiss, Tom and Raffiq, Sayda and Kätzel, Dennis and Miesenböck, Gero and Butt, Simon J.B. (2016) GABAergic interneurons form transient layer-specific circuits in early postnatal neocortex. Nature Communications, 7. ISSN 2041-1723

[img]
Preview
Text (Anastasiades-etal-NC2016-GABAergic-interneurons-form-transient-layer-specific-circuits-in-early-postnatal-neocortex)
Anastasiades_etal_NC2016_GABAergic_interneurons_form_transient_layer_specific_circuits_in_early_postnatal_neocortex.pdf
Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (1MB)| Preview

    Abstract

    GABAergic interneurons play key roles in cortical circuits, yet little is known about their early connectivity. Here we use glutamate uncaging and a novel optogenetic strategy to track changes in the afferent and efferent synaptic connections of developing neocortical interneuron subtypes. We find that Nkx2-1-derived interneurons possess functional synaptic connections before emerging pyramidal cell networks. Subsequent interneuron circuit maturation is both subtype and layer dependent. Glutamatergic input onto fast spiking (FS), but not somatostatin-positive, non-FS interneurons increases over development. Interneurons of both subtype located in layers (L) 4 and 5b engage in transient circuits that disappear after the somatosensory critical period. These include a pathway mediated by L5b somatostatin-positive interneurons that specifically targets L4 during the first postnatal week. The innervation patterns of immature cortical interneuron circuits are thus neither static nor progressively strengthened but follow a layer-specific choreography of transient connections that differ from those of the adult brain.