Deep brain optical measurements of cell type-specific neural activity in behaving mice.
Recent advances in genetically encoded fluorescent sensors enable the monitoring of cellular events from genetically defined groups of neurons in vivo. In this protocol, we describe how to use a time-correlated single-photon counting (TCSPC)-based fiber optics system to measure the intensity, emission spectra and lifetime of fluorescent biosensors expressed in deep brain structures in freely moving mice. When combined with Cre-dependent selective expression of genetically encoded Ca(2+) indicators (GECIs), this system can be used to measure the average neural activity from a specific population of cells in mice performing complex behavioral tasks. As an example, we used viral expression of GCaMPs in striatal projection neurons (SPNs) and recorded the fluorescence changes associated with calcium spikes from mice performing a lever-pressing operant task. The whole procedure, consisting of virus injection, behavior training and optical recording, takes 3-4 weeks to complete. With minor adaptations, this protocol can also be applied to recording cellular events from other cell types in deep brain regions, such as dopaminergic neurons in the ventral tegmental area. The simultaneously recorded fluorescence signals and behavior events can be used to explore the relationship between the neural activity of specific brain circuits and behavior.
Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA.
Guohong
G
Cui
Department of Electronics Engineering, Ewha Womans University, Seoul, Korea.
Sang Beom
SB
Jun
1] Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA. [2] Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, USA.
Xin
X
Jin
Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA.
Guoxiang
G
Luo
Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA.
Michael D
MD
Pham
1] Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA. [2] Section on Synaptic Pharmacology, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA.
David M
DM
Lovinger
Section on Cellular Biophotonics, Laboratory for Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA.
Steven S
SS
Vogel
1] Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA. [2] Champalimaud Neuroscience Programme at Instituto Gulbenkian de Ciência, Oeiras, Portugal. [3] Champalimaud Centre for the Unknown, Lisbon, Portugal.
Rui M
RM
Costa
D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D001921:Brain / Q000166:cytology*; D001931:Brain Mapping / Q000379:methods*; D005336:Fiber Optic Technology / Q000379:methods; D005453:Fluorescence; D059907:Functional Neuroimaging / Q000379:methods*; D051379:Mice; D009043:Motor Activity / Q000502:physiology*; D009474:Neurons / Q000378:metabolism*; D017785:Photons