title: In Vivo Monosynaptic Excitatory Transmission between Layer 2 Cortical Pyramidal Neurons.
abstract: Little is known about the properties of monosynaptic connections between identified neurons in vivo. We made multiple (two to four) two-photon targeted whole-cell recordings from neighboring layer 2 mouse somatosensory barrel cortex pyramidal neurons in vivo to investigate excitatory monosynaptic transmission in the hyperpolarized downstate. We report that pyramidal neurons form a sparsely connected (6.7% connectivity) network with an overrepresentation of bidirectional connections. The majority of unitary excitatory postsynaptic potentials were small in amplitude (<0.5 mV), with a small minority >1 mV. The coefficient of variation (CV = 0.74) could largely be explained by the presence of synaptic failures (22%). Both the CV and failure rates were reduced with increasing amplitude. The mean paired-pulse ratio was 1.15 and positively correlated with the CV. Our approach will help bridge the gap between connectivity and function and allow investigations into the impact of brain state on monosynaptic transmission and integration.
authors.affiliation: Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Robert-Rössle-Strasse 10, 13092 Berlin, Germany; Cluster of Excellence NeuroCure, Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Jouhanneau
authors.affiliation: Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Robert-Rössle-Strasse 10, 13092 Berlin, Germany; Cluster of Excellence NeuroCure, Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Department of Biology, Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Philippstrasse 13, 10115 Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kremkow
authors.affiliation: Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Robert-Rössle-Strasse 10, 13092 Berlin, Germany; Cluster of Excellence NeuroCure, Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.
authors.forename: Anja L
authors.initials: AL
authors.lastname: Dorrn
authors.affiliation: Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Robert-Rössle-Strasse 10, 13092 Berlin, Germany; Cluster of Excellence NeuroCure, Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany. Electronic address: james.poulet@mdc-berlin.de.
authors.forename: James F A
authors.initials: JF
authors.lastname: Poulet
mesh_terms: D000818:Animals; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*