Figure 6.

Positive correlation between activity patterns of glomeruli innervated by multi-glomerular MTCs decreases with inter tuft distance

(A) Schematic of electroporation of a single, multi-glomerular MTC (magenta) in the lateral olfactory bulb of tubb2b:GCaMP6s tadpoles (dark green).

(B) Scatterplots of properties of glomeruli associated with individual multi-glomerular MTCs (n = 16, color and symbols indicate MTCs). Shown are mean Euclidean distance of linked glomeruli plotted against the glomerular cross-sectional area and against the mean correlation coefficient between fluorescent time traces of connected glomeruli. Inverse relation between signal to background ratio and glomerular cross-sectional area or mean correlation coefficient between fluorescent time traces of connected glomeruli. Linear regression lines indicate negative or positive relations between the compared factors, gray shadings the confidence interval. ∗∗∗, p ≤ 0.001; ns, not significant, p > 0.05.

(C–E) 3D Reconstructions representative for three types of multi-glomerular MTCs. Raw fluorescence traces of glomerular calcium responses (color indicates the region of interest), correlation matrices between the raw fluorescence traces (Pearson’s correlation coefficient) are shown. Inlays with individual image planes showing association of dendritic tufts (magenta) and reactive glomeruli (fluorescence intensity difference maps to amino acids, H, red; R, blue; W, yellow). Scale bar equals 20 µm. (C) A multi-glomerular MTC with highly correlated response profiles in glomerular regions. (D) MTC with similar odor tuning, but differences in lower amplitude responses. (E) MTC with no clear responses with amplitudes above noise level in the glomerular regions innervated by tufted dendrites (correlation coefficients around 0 between region time courses). Stimuli abbreviations see Figure 2A and methods section.