Fig. 4

Fig. 4

20 Hz imaging of zebrafish forebrain. a Maximum intensity projection of voxelwise F (grayscale) and ΔF/F (magenta) along the dorsal-ventral axis of the larval zebrafish forebrain (5 dpf) with pan-neuronal GCaMP6f expression (HuC:GCaMP6f) acquired at 20 stacks/s at 10× magnification (Supplementary Movie 2). Only voxels with greater than 15% ΔF/F are colored. b Raster plot of ΔF/F within 629 manually segmented neuron ROIs over a 4 min period. Shown is an excerpt from a 20 min recording. ROIs were drawn smaller than the size of each cell in an attempt to minimize the effects of motion artifacts and cross-talk between nearby neurons. c Neurons exhibit a range of pairwise correlations in the ΔF signal. Correlations were computed with highpass-filtered neuron traces (1.0 Hz cutoff) in order to focus on relationships revealed by high sampling rate. Neurons are ordered by axial depth in the forebrain (dorsal to ventral). d Power spectra of the ΔF signals for a subset of neurons show that power diminishes gradually with increasing frequency. These and many other neurons exhibit peaks in their spectra at 2.5 Hz and 7.5 Hz that correspond with the larval zebrafish heart rhythm³⁵. e Bandstop filters were applied to remove the heartbeat frequency bands (see Methods section) before recomputing correlations. Shown is the matrix of differences in correlation values obtained before and after heartbeat artifact removal (corr_after − corr_before). Thus this matrix highlights spurious correlations due to heartbeat that could contaminate a naive analysis of neuronal activity