Fluorescence-based monitoring of in vivo neural activity using a circuit-tracing pseudorabies virus.
The study of coordinated activity in neuronal circuits has been challenging without a method to simultaneously report activity and connectivity. Here we present the first use of pseudorabies virus (PRV), which spreads through synaptically connected neurons, to express a fluorescent calcium indicator protein and monitor neuronal activity in a living animal. Fluorescence signals were proportional to action potential number and could reliably detect single action potentials in vitro. With two-photon imaging in vivo, we observed both spontaneous and stimulated activity in neurons of infected murine peripheral autonomic submandibular ganglia (SMG). We optically recorded the SMG response in the salivary circuit to direct electrical stimulation of the presynaptic axons and to physiologically relevant sensory stimulation of the oral cavity. During a time window of 48 hours after inoculation, few spontaneous transients occurred. By 72 hours, we identified more frequent and prolonged spontaneous calcium transients, suggestive of neuronal or tissue responses to infection that influence calcium signaling. Our work establishes in vivo investigation of physiological neuronal circuit activity and subsequent effects of infection with single cell resolution.
Granstedt
Andrea E
AE
Department of Molecular Biology, Neuroscience Institute, Princeton University, Princeton, New Jersey, United States of America.
Szpara
Moriah L
ML
Kuhn
Bernd
B
Wang
Samuel S-H
SS
Enquist
Lynn W
LW
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D004583:Electrons; D005456:Fluorescent Dyes / Q000494:pharmacology*; D005724:Ganglia / Q000378:metabolism; D011558:Herpesvirus 1, Suid / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D008959:Models, Neurological; D009474:Neurons / Q000378:metabolism*; D011336:Probability; D012463:Saliva / Q000378:metabolism; D013997:Time Factors
D005456:Fluorescent Dyes; D002118:Calcium