Figure 7.

Voxel-Based Analysis of Calcium Signal in Amacrine Cells Reveals Diversity in Temporal Tuning

(A) Left: view of the IPL showing amacrine cells expressing SyGCaMP3 (left) and the respective pixel-mask (right). Scale bar represents 20 μm. Right: raster plot showing the relative change in fluorescence for 6,210 pixels during a “forward” frequency seep. Only OFF voxels are shown, as defined by the responses to steps of light.

(B and C) K-means clustering revealed two major types of temporal tuning in amacrine cells, “low” band-pass (B, peak transmission at 4.6 ± 0.2 Hz and fc = 9.8 ± 0.11 Hz) and “high” band-pass (C, peak transmission at 9.9 ± 0.3 Hz and fc = 13.9 ± 0.2 Hz). Voxels were then separated further into ON (green), OFF (red), and ON-OFF (blue). Results were collected from five fish. The left-hand plots show averaged SyGCaMP3 responses of the three groups classified as low and high band-pass from a total of between 5,207 and 8,540 voxels from five fish. The right-hand plots show response amplitude as a function of frequency.

(D) Spatial distribution within the IPL of low band-pass (filled gray regions) and high band-pass (solid lines) voxels as a function of dendrite stratification in the IPL for ON (left), OFF (middle), and ON-OFF (right) pixels. Stratification is plotted such that 0% is the boundary with the ganglion cell layer and 100% the boundary with the inner nuclear layer.