Fig. 2: Protection to CA1 neurons conferred by 40 Hz light treatment.

a Coronal brain sections were stained with FJB. Hippocampal areas were shown in a highlighting 2VO-induced CA1 degenerating neurons (bright green colored cells). Scale bars = 50 µm. b Enlarged CA1 area from 3 d, 7 d, and 14 d after 2VO with or without 40 Hz light treatment. Scale bars = 20 µm. The last column of b showed 40 Hz light treatment at 3 d after 2VO. c and d Quantification of CA1 FJB positive neurons within CA1 (n = 6 mice each group in c; LED after 2VO 2 h: n = 6 mice; LED after 2VO 3d: n = 5 mice). e 2VO mice were treated with different rhythmic frequencies, and arrhythmic frequency of lights and FJB staining was performed 3 d after 2VO. n = 6 mice in 2VO and 40 Hz groups; n = 4 mice in Random group; n = 5 mice in other groups. Data represent the mean ± SEM. Error bars indicate SEM. ^## indicates a comparison between 2VO and 2VO + LED group. *indicates a comparison between 2VO + LED group received 40 Hz light 2 h or 3 d after 2VO surgery, and ** in panel e indicates a comparison between the random group and 2VO mice received different frequencies of light treatment (*,^#P < 0.05, and **P < 0.01). The test used in c: 2ANOVA with LSD’s post hoc analysis; d Two-tailed unpaired t-test; e 1ANOVA with Dunnett’s post hoc test. Source data are provided as a Source Data file.