{Reference Type}: Journal Article {Title}: Layer 1 NDNF interneurons are specialized top-down master regulators of cortical circuits. {Author}: Hartung J;Schroeder A;Péréz Vázquez RA;Poorthuis RB;Letzkus JJ; {Journal}: Cell Rep {Volume}: 43 {Issue}: 5 {Year}: 2024 May 28 暂无{DOI}: 10.1016/j.celrep.2024.114212 {Abstract}: Diverse types of inhibitory interneurons (INs) impart computational power and flexibility to neocortical circuits. Whereas markers for different IN types in cortical layers 2-6 (L2-L6) have been instrumental for generating a wealth of functional insights, only the recent identification of a selective marker (neuron-derived neurotrophic factor [NDNF]) has opened comparable opportunities for INs in L1 (L1INs). However, at present we know very little about the connectivity of NDNF L1INs with other IN types, their input-output conversion, and the existence of potential NDNF L1IN subtypes. Here, we report pervasive inhibition of L2/3 INs (including parvalbumin INs and vasoactive intestinal peptide INs) by NDNF L1INs. Intersectional genetics revealed similar physiology and connectivity in the NDNF L1IN subpopulation co-expressing neuropeptide Y. Finally, NDNF L1INs prominently and selectively engage in persistent firing, a physiological hallmark disconnecting their output from the current input. Collectively, our work therefore identifies NDNF L1INs as specialized master regulators of superficial neocortex according to their pervasive top-down afferents.