Extended Data Figure 3. Time-course of rabies tracing and recordings.
(a) Viability of postsynaptic neurons as a function of day after the rabies virus injection, based on N = 17 injections. (b) Count of observed presynaptic neurons traced over the same period from N = 17 postsynaptic neurons (mean ± s.e.m.). (c) Fraction of viable presynaptic neurons (red) over the total traced (grey), and worst-case scenario population mortality of presynaptic neurons (dashed), estimated assuming the viability of each newly labelled presynaptic neuron degrades at the same rate as the viability of the postsynaptic neurons measured in a. (d) Average distribution across animals (N = 17, mean ± s.e.) of the imaging sessions used to record the responses of presynaptic neurons, split by cortical layer. The time of imaging did not systematically change across layer (red triangle, median, first and third quartiles), and most of the data was acquired before presynaptic neurons suffer from the toxicity of the rabies virus. (e) Distribution of responsivity of the presynaptic neurons across days (red violin plot with black median). Responsivity was measured as the maximum average stimulus-triggered response. To compare across sessions, presynaptic responsivity was normalised to the median responsivity of the local population (shaded line). (f) Longitudinal imaging of presynaptic neurons identified before (left, black ROI) and 5-12 days after (right, red ROI) rabies virus infection. Scale bar 25 μm. (g) Average responses to drifting gratings of the same presynaptic neurons before (black) and after (red) the rabies virus infection. Responses (4 s long) were z-scored with the respect to blank trials. Scale bar 1 std. (h) Preferred orientation of presynaptic neurons recorded before and after the rabies virus infection. At the time of recording used in this study, the preferred orientation of presynaptic neurons is unperturbed by the rabies virus infection (n = 51 neurons from N = 4 animals, circular correlation 0.76, pr = 1.6*10-6, Z-test).