Fig. 6: Three distinct groups of SCN neurons with different time-dependent light responses.

a Representative light response analysis from 3 neurons. Three possible results are demonstrated here, including that the Z-score of the specific time point is significantly higher (orange), lower (blue), or not significantly changed (grey) compared to the baseline (one-way ANOVA and Tukey test). b The results in (a) are plotted together. Neurons are classified into three groups according to their significance pattern across all time points, separated by dotted lines. Group 1 neurons (green) are specific activated at ZT 16. Group 2 neurons (red) are specifically inhibited at ZT 22. While group 3 neurons (grey) do not show consistent positive or negative light response. c Averaged light-response traces from three groups of neurons at different time points. d Group 1 neurons show significantly higher activation clusters (C1 - 4) at ZT 16 and group 2 neurons show significantly higher inhibition clusters (C5 - 6) at ZT 22. Numbers indicate p-values from one-way ANOVA, Tukey post hoc tests. Error bars indicate mean with SEM. e Haar feature analysis of all neurons for each ZT using 18 bins of 5 sec average fluorescence intensity. f Neuron trajectories in the Haar-ZT space show distinct characters from three groups. g Neuron groups are labeled on the raw images. Green dots indicate the cell body of group 1 neurons, red dots indicate group 2 neurons, while grey dots indicate group 3 neurons. Scale bars are 100 μm, according to the imaging side of the GRIN endoscope. n = 3 animals.