Stimulation of the SCN region drives a variety of GABA and glutamate driven responses in downstream target neurons. a Schematic of typical ex vivo recording and stimulation configuration (left) and proportions of isolated neurons exhibiting various classes of response to electrical stimulation as a function of dorsal-ventral location (right; n.r. indicates non-responsive cells). b Box and whisker plot showing distribution of response latencies (time to response onset) for various responsive cell classes. Data analysed by mixed-effects linear model (F4,120 = 3.3, P = 0.01) with Sidak’s post-tests. c–g Peri-stimulus raster plots from example cells (top) and mean ± SEM change in firing across the population of cells subdivided based on their responsive to electrical stimulation and its sensitivity to antagonists of fast ionotropic GABA and glutamate signalling. h, i Mean ± SEM response (peak change in firing occurring within 100 ms post stimulation) for the five identified classes of neurons (corresponding to those illustrated in c–g) under baseline and following antagonist treatment. Data analysed by mixed-effects linear model (h F2,53.0 = 37.3, P < 0.001; i F2,18.3 = 25.8, P < 0.001; j F2,11.7 = 4.2, P = 0.04; k F2,46.7 = 45.5, P < 0.001; l F2,15.6 = 6.3, P = 0.01) with Sidak’s post-tests. *, **, *** = P < 0.05, P < 0.01 and P < 0.001 vs. baseline. #, ### indicates P < 0.05 and P < 0.001 vs. BIC alone. Raw data values used for statistical analysis can be found in Additional file 8.