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. Author manuscript; available in PMC: 2009 Mar 13.
Published in final edited form as: Neuron. 2008 Mar 13;57(5):634–660. doi: 10.1016/j.neuron.2008.01.002

Figure 6. Strategies for Imaging Genetically Specified Neuronal Populations with [Ca2+] Indicators.

Figure 6

(A) All neurons are labeled nondiscriminately by bulk-loading with a [Ca2+] indicator (diffuse green). A genetically specified set of neurons express a fluorescent protein (yellow).

(B) [Ca2+] imaging in mice expressing GFP in GABAergic interneurons. (Top) Image showing neurons bulk-loaded with [Ca2+] indicator. GFP fluorescence is overlaid in green. (Bottom) Responses of GFP-negative and GFP-positive (GABAergic) neurons to oriented bars. Modifed from Sohya et al., 2007.

(C) A genetically specified subpopulation of neurons express a protein (such as tetracysteine motifs; blue) that makes them susceptible to labeling by modified versions of [Ca2+] indicators (such as biarsenicals; green).

(D) A genetically specified subpopulation of neurons express a genetically encoded [Ca2+] indicator (green).

(E–G) Imaging odor-evoked activity in Kenyon cells of the Drosophila mushroom body using genetically encoded [Ca2+] indicators (G-CaMP1.3) in vivo. (E) G-CaMP fluorescence showing the mushroom body. (F) Two responses to the same odor (difference image; 2 s after odor onset minus baseline). Two Kenyon cells show strong activity. (G) Time course of G-CaMP responses. Modified from Wang et al., 2004.