title: Validation of optical voltage reporting by the genetically encoded voltage indicator VSFP-Butterfly from cortical layer 2/3 pyramidal neurons in mouse brain slices.
abstract: Understanding how behavior emerges from brain electrical activity is one of the ultimate goals of neuroscience. To achieve this goal we require methods for large-scale recording of the electrical activity of specific neuronal circuits. A very promising approach is to use optical reporting of membrane voltage transients, particularly if the voltage reporter is genetically targeted to specific neuronal populations. Targeting in this way allows population signals to be recorded and interpreted without blindness to neuronal diversity. Here, we evaluated the voltage-sensitive fluorescent protein, VSFP Butterfly 2.1, a genetically encoded voltage indicator (GEVI), for monitoring electrical activity of layer 2/3 cortical pyramidal neurons in mouse brain slices. Standard widefield fluorescence and two-photon imaging revealed robust, high signal-to-noise ratio read-outs of membrane voltage transients that are predominantly synaptic in nature and can be resolved as discrete areas of synaptically connected layer 2/3 neurons. We find that targeted expression of this GEVI in the cortex provides a flexible and promising tool for the analysis of L2/3 cortical network function.
authors.affiliation: Department of Physiology, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand ruth.empson@otago.ac.nz.
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Empson
authors.affiliation: Department of Physiology, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: Chelsea
authors.initials: C
authors.lastname: Goulton
authors.affiliation: Department of Physiology, Brain Health Research Centre, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand.
authors.forename: David
authors.initials: D
authors.lastname: Scholtz
authors.affiliation: The Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom.
authors.forename: Yasir
authors.initials: Y
authors.lastname: Gallero-Salas
authors.affiliation: Allen Institute for Brain Science, Seattle, Washington.
authors.forename: Hongkui
authors.initials: H
authors.lastname: Zeng
authors.affiliation: The Division of Brain Sciences, Department of Medicine, Imperial College London, London, United Kingdom.
authors.forename: Thomas
authors.initials: T
authors.lastname: Knöpfel
keywords: Cortex; L2/3; genetically encoded voltage indicator; optogenetics; voltage imaging