Fig. 4.
The circadian canonical clock within the SCN is necessary but not sufficient for fear entrainment. (A) Schematic representation of the genetic strategy used to knock out mBmal1 in the SCN. A Bmal1fx/fx mouse is bilaterally injected with a Cre-expressing AAV in the SCN. (B) Representative foraging actograms from an SCN-Bmal1+/+ control mouse (Left) and two SCN-Bmal1−/− mice (Center and Right) subjected to cyclic fear under DD. (C) FFT amplitude across the successive experimental stages from SCN-Bmal1+/+ mice (Left, n = 4) and SCN-Bmal1−/− mice (Right, n = 6). (D) Schematic representation of the genetic strategy to rescue Bmal1 expression in the SCN. A Cami-Bmal1−/− mouse is bilaterally injected with Cre-dependent Bmal1-expressing AAV. (E) Representative foraging actograms from Cami-Bmal1−/−-SCN-Bmal1−/− mouse (Left) and Cami-Bmal1−/−-SCN-Bmal1+/+ mouse (Right) subjected to the noncued fear protocol in DD. (F) Rayleigh plots representing the phase of activity onset in the postshock phase of Cami-Bmal1−/−-SCN-Bmal1+/+ mice relative to the shock phase (Left) or to the baseline phase (Right). Asterisks indicate statistically significant differences according to Tukey comparisons following LMM analysis: *P < 0.05, **P < 0.01.