Journal: bioRxiv
Article Title: Pyramidal-cell-specific hemispheric asymmetry shapes dorsoventral CA1 dynamics during rest and exploratory behavior
doi: 10.64898/2026.05.15.725448
Figure Lengend Snippet: (A) Experimental timeline. Five-to-six-week-old male C57BL/6J mice received contralateral viral injections of AAV-CaMKIIα-jGCaMP8s and AAV-SynI-jRCaMP1b into dorsal CA1 (dCA1) and ventral CA1 (vCA1), followed by optic fiber implantation. Dual-site fiber photometry recordings were obtained during home cage behavior on day 35, after handling and habituation, and ex vivo validation was performed on day 36. (B) Representative fluorescence images of jGCaMP8s (green) and jRCaMP1b (red) expression in dorsal and ventral hippocampus. KCl stimulation (30 mM, > 5 min) evoked robust fluorescence increases at both indicator wavelengths, confirming sensor functionality at all four recording sites. Scale bar: 500µm. (C, D) Representative 60-s Z-scored CaMKIIα-jGCaMP8s calcium traces from contralateral dorsal-ventral CA1 recordings during home cage behavior in the LdCA1↔RvCA1 (C) and RdCA1↔LvCA1 (D) configurations. Detected calcium events are marked. (E, F) In the LdCA1↔RvCA1 configuration, peak event number (E) and peak frequency (F) did not differ significantly between dorsal and ventral CA1. (G, H) In the RdCA1↔LvCA1 configuration, LvCA1 showed significantly higher peak event number (G) and peak frequency (H) than RdCA1. (I, J) Hemispheric comparison within dorsal CA1. Left dCA1 exhibited significantly higher peak event number (I) and peak frequency (J) than right dCA1, indicating a CaMKIIα-defined dorsal CA1 hemispheric asymmetry. (K, L) Left and right ventral CA1 did not differ in peak event number (K) or peak frequency (L). (M-P) SynI-jRCaMP1b recordings showed no significant dorsoventral differences in either the LdCA1↔RvCA1 (M, N) or the RdCA1↔LvCA1 (O, P) configuration. (Q-T) SynI-jRCaMP1b recordings showed no significant left-right differences within dorsal CA1 (Q, R) or within ventral CA1 (S, T). Data points represent animal-level values. Connected lines in panels E-H and M-P indicate paired dorsal-ventral recordings obtained simultaneously from the same animal. Data are presented as mean ± SEM. Statistics: Normality was assessed using the Shapiro-Wilk test. Within-animal dorsoventral comparisons (E-H, M-P) were analyzed using paired two-tailed t-tests. Hemispheric comparisons (I-L, Q-T) compared signals across animals between the two configurations and were analyzed using unpaired two-tailed Welch’s t-tests. Exact p-values and test statistics are reported in Table_statistical_analyses. **p < 0.01. Sample sizes. LdCA1↔RvCA1, n = 13 mice; RdCA1↔LvCA1, n = 13 mice.
Article Snippet: Male wild-type C57BL/6J mice (Jackson Laboratory, Bar Harbor, ME, USA) were used for all experiments.
Techniques: Ex Vivo, Biomarker Discovery, Fluorescence, Expressing, Comparison, Two Tailed Test
