title: Imaging light responses of targeted neuron populations in the rodent retina.
abstract: Decoding the wiring diagram of the retina requires simultaneous observation of activity in identified neuron populations. Available recording methods are limited in their scope: electrodes can access only a small fraction of neurons at once, whereas synthetic fluorescent indicator dyes label tissue indiscriminately. Here, we describe a method for studying retinal circuitry at cellular and subcellular levels combining two-photon microscopy and a genetically encoded calcium indicator. Using specific viral and promoter constructs to drive expression of GCaMP3, we labeled all five major neuron classes in the adult mouse retina. Stimulus-evoked GCaMP3 responses as imaged by two-photon microscopy permitted functional cell type annotation. Fluorescence responses were similar to those measured with the small molecule dye OGB-1. Fluorescence intensity correlated linearly with spike rates >10 spikes/s, and a significant change in fluorescence always reflected a significant change in spike firing rate. GCaMP3 expression had no apparent effect on neuronal function. Imaging at subcellular resolution showed compartment-specific calcium dynamics in multiple identified cell types.
authors.affiliation: Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147, USA. borghuisb@janelia.hhmi.org
authors.forename: Bart G
authors.initials: BG
authors.lastname: Borghuis
authors.forename: Lin
authors.initials: L
authors.lastname: Tian
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.forename: Sergei S
authors.initials: SS
authors.lastname: Nikonov
authors.forename: Noga
authors.initials: N
authors.lastname: Vardi
authors.forename: Boris V
authors.initials: BV
authors.lastname: Zemelman
authors.forename: Loren L
authors.initials: LL
authors.lastname: Looger
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000145:classification / Q000166:cytology / Q000502:physiology*; D009924:Organ Culture Techniques; D012160:Retina / Q000166:cytology / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*; D056969:Voltage-Sensitive Dye Imaging / Q000379:methods*