Imaging brain electric signals with genetically targeted voltage-sensitive fluorescent proteins


Cortical information processing relies on synaptic interactions between diverse classes of neurons with distinct electrophysiological and connection properties. Uncovering the operational principles of these elaborate circuits requires the probing of electrical activity from selected populations of defined neurons. Here we show that genetically encoded voltage-sensitive fluorescent proteins (VSFPs) provide an optical voltage report from targeted neurons in culture, acute brain slices and living mice. By expressing VSFPs in pyramidal cells of mouse somatosensory cortex, we also demonstrate that these probes can report cortical electrical responses to single sensory stimuli in vivo. These protein-based voltage probes will facilitate the analysis of cortical circuits in genetically defined cell populations and are hence a valuable addition to the optogenetic toolbox.

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Figure 1: VSFP2.3 reports membrane voltage transients through differential two-color fluorescence.
Figure 2: Distribution and voltage responses of VSFP2.3 in the mouse cerebral cortex.
Figure 3: VSFP2.3 reports synaptic responses in individual pyramidal neurons from acute brain slices in single trials.
Figure 4: VSFP2.3 imaging in the somatosensory cortex of living mice.
Figure 5: VSFP2.42 reports cortical responses to deflections of a single whisker.
Figure 6: Construction of receptive field maps using in vivo VSFP2 imaging.


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We thank all members of the Knöpfel laboratory for comments and invaluable technical help, T. Shimogori and R. Yoshida for in utero electroporation of VSFP plasmids, and Thomas Behnisch for his participation in initial in vivo experiments. This work was funded by grants from RIKEN Brain Science Institute (T.K.), the RIKEN Brain Science Institute director's fund (T.K.), US National Institutes of Health grant NS057631 (T.K.), a grant from the Ministry of Education, Culture, Sports, Science and Technology (MEXT, H.M.), the Japanese Society for the Promotion of Science–Canadian Institutes of Health Research postdoctoral fellowship program (A.P.), a grant-in-aid for Japanese Society for the Promotion of Science fellows (A.P.) and La Fondation pour les Sciences du Cerveau (J.R.).

Author information

W.A., H.M., A.P. and T.K. conceived and designed the experiments. A.P. developed VSFP2.42. H.M. performed recordings in cultured cells. W.A. performed experiments in acute brain slices. W.A., H.M. and T.K. performed in vivo imaging experiments. W.A., H.M., A.P., J.R. and T.K. contributed to data analysis, preparation of figures and writing of the manuscript.

Correspondence to Thomas Knöpfel.

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Supplementary Figures 1–6 and Supplementary Table 1 (PDF 399 kb)

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Akemann, W., Mutoh, H., Perron, A. et al. Imaging brain electric signals with genetically targeted voltage-sensitive fluorescent proteins. Nat Methods 7, 643–649 (2010).

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