RT Journal Article SR Electronic T1 Sparse recurrent excitatory connectivity in the microcircuit of the adult mouse and human cortex JF bioRxiv FD Cold Spring Harbor Laboratory SP 292706 DO 10.1101/292706 A1 Stephanie C. Seeman A1 Luke Campagnola A1 Pasha A. Davoudian A1 Alex Hoggarth A1 Travis A. Hage A1 Alice Bosma-Moody A1 Christopher A. Baker A1 Jung Hoon Lee A1 Stefan Mihalas A1 Corinne Teeter A1 Andrew L. Ko A1 Jeffrey G. Ojemann A1 Ryder P. Gwinn A1 Daniel L. Silbergeld A1 Charles Cobbs A1 John Phillips A1 Ed Lein A1 Gabe J. Murphy A1 Christof Koch A1 Hongkui Zeng A1 Tim Jarsky YR 2018 UL http://biorxiv.org/content/early/2018/05/08/292706.abstract AB Generating a comprehensive description of cortical networks requires a large-scale, systematic approach. To that end, the Allen Institute is engaged in a pipeline project using multipatch electrophysiology, supplemented with 2-photon optogenetics, to characterize connectivity and synaptic signaling between classes of neurons in adult mouse and human cortex. We focus on producing results detailed enough for the generation of computational models and enabling comparison with future studies. Here we report our examination of intralaminar connectivity within each of several classes of excitatory neurons. We find that connections are sparse but present among all excitatory cell types and layers we sampled, with the most sparse connections in layers 5 and 6. Almost all mouse synapses exhibited short-term depression with similar dynamics. Synaptic signaling between a subset of layer 2/3 neurons; however, exhibited facilitation. These results contribute to a body of evidence describing recurrent excitatory connectivity as a conserved feature of cortical microcircuits.