Stereotyped odor-evoked activity in the mushroom body of Drosophila revealed by green fluorescent protein-based Ca2+ imaging.
To study the representation of olfactory information in higher brain centers, we expressed a green fluorescent protein-based Ca2+ sensor, G-CaMP, in the Drosophila mushroom body (MB). Using two-photon microscopy, we imaged odor-evoked G-CaMP fluorescence transients in MB neurons [Kenyon cells (KCs)] with single-cell resolution. Odors produced large fluorescence transients in a subset of KC somata and in restricted regions of the calyx, the neuropil of the MB. In different KCs, odor-evoked fluorescence transients showed diverse changes with odor concentration: in some KCs, fluorescence transients were evoked by an odor at concentrations spanning several orders of magnitude, whereas in others only at a narrow concentration range. Different odors produced fluorescence transients in different subsets of KCs. The spatial distributions of KCs showing fluorescence transients evoked by a given odor were similar across individuals. For some odors, individual KCs with fluorescence transients evoked by a particular odor could be found in similar locations in different flies with spatial precisions on the order of the size of KC somata. These results indicate that odor-evoked activity can have remarkable spatial specificity in the MB.
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
Yalin
Y
Wang
Hui-Fu
HF
Guo
Thomas A
TA
Pologruto
Frances
F
Hannan
Inessa
I
Hakker
Karel
K
Svoboda
Yi
Y
Zhong
D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D004330:Drosophila / Q000166:cytology / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000032:analysis*; D049408:Luminescent Agents / Q000032:analysis*; D036641:Microscopy, Fluorescence, Multiphoton; D024521:Mushroom Bodies / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000378:metabolism*; D009812:Odorants
D049408:Luminescent Agents; D049452:Green Fluorescent Proteins; D002118:Calcium