Optical probing of neuronal circuits with calcium indicators.
An experimental difficulty in unraveling circuits in the mammalian nervous system is the identification of postsynaptic targets of a given neuron. Besides ultrastructural reconstructions, simultaneous recordings from pairs of cells in brain slices have been used to identify connected neurons. We describe in this paper a technique using calcium imaging that allows rapid identification of potential postsynaptic targets. This method consists of stimulating one neuron ("trigger") while imaging a population of cells to detect which other neurons ("followers") are activated by the trigger. By using bulk-loading of calcium indicators in slices of mouse visual cortex, we demonstrate that neurons that display somatic calcium transients time-locked to the spikes of a trigger neuron can be monosynaptically connected to it. This technique could be applied to reconstruct and assay circuits in the central nervous system.
Peterlin
Z A
ZA
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Kozloski
J
J
Mao
B Q
BQ
Tsiola
A
A
Yuste
R
R
D000818:Animals; D002118:Calcium / Q000502:physiology*; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives; D066298:In Vitro Techniques; D008274:Magnesium; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000502:physiology*; D055095:Optics and Photonics; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*
D005456:Fluorescent Dyes; C049925:fura-2-am; D008274:Magnesium; D002118:Calcium; D016257:Fura-2