Removing direct photocurrent artifacts in optogenetic connectivity mapping data via constrained matrix factorization
Fig 7
PhoRC allows ensemble mapping in the presence of photocurrent artifacts.
a, Cartoon depicting the photocurrent contamination problem with ensemble grid stimulation. Red circle denotes region where stimulation will evoke direct photocurrent. If one grid point in an ensemble evokes photocurrent, the entire measurement will be corrupted. b, Inferred grid connections before and after photocurrent subtraction. ROI denotes location of a putative connection. c, Observed and subtracted traces from the ROI selected in b. Traces from this ROI contain direct photocurrents whenever a different target in the ensemble evokes direct photocurrent. d, Inferred waveforms for each putative connection before and after subtraction. e-h, Same as a-d but for the targeted mapping design. e, Cartoon depicting the photocurrent contamination problem with ensemble targeted stimulation. As in a, red circle denotes region where stimulation evokes direct photocurrent. f, Schematic of inferred connectivity before and after subtracting photocurrents, Z projection. ROI corresponds to a region far from the postsynaptic cell (green cross), but photocurrents are still present due to the use of ensemble mapping. g, Observed and subtracted currents from the ROI shown in f. h, Inferred waveforms for each putative connection before and after subtraction.