Fig. 1: The transfer function between neuronal and vascular responses within a single glomerulus: computation and robustness across mice.

a Left, schematics of the dorsal olfactory bulb (OB) of a mouse expressing YFP and GCaMP6f under the control of M72 and Thy1 promoters, respectively. Depending on the odor concentration, ethyl tiglate (ET) activates several glomeruli or only the most responsive one, which is in close vicinity to the M72 glomerulus. Right top, axons converging in the two M72 glomeruli are imaged with a stereoscope through a chronically implanted PMP window (photographs were taken for all mice). Right bottom, an image showing a capillary labeled with Texas red. A broken line is used in the linescan acquisition mode to monitor Ca²⁺ in the neuropil (dendritic GCaMP6f) and RBC velocity in the capillary. b For each mouse, a microscopic transfer function (μTF) is convolved with Ca²⁺ signals, the μTF being optimized to predict RBC velocity changes in response to odor 1% ET (5 s). c Top, μTFs optimized for each mouse (n = 15). The orange curve is the μTF optimized from Ca²⁺ and RBC velocity responses illustrated in bottom, which gives the prediction curve overlaid in orange on the RBC response. d Quantification (mean ± SD, n = 15 mice) of prediction robustness for each μTFs optimized using either the TF derived from the same mouse (black symbols, single self prediction) or data from other mice (blue symbols, mean cross-validation). The μTF from mouse #1 (square symbols) gives the best ‘self’ vascular prediction (see c) and good predictions across mice. It was selected as the standard μTF to predict vascular responses from Ca²⁺ responses. Gray shadow (#12–15) for Pearson coefficients obtained with data acquired in mice from Boido et al, 2019²². e Examples of vascular response predictions from three mice using the standard microscopic TF and optimized for the amplitude (see Methods). Source data are provided as a Source Data file.