Fig. 5. Co-reactivation between the overlap and neutral ensembles occurs during more wake than during sleep.

a, Schematic of the GRIN lens and electrode implants used for this experiment (left). Mice were injected with AAV1-Syn-GCaMP6f in the dorsal CA1. Then, 2 weeks later, the mice were implanted with a lens above the injection site, with two EEG electrodes and two EMG electrodes. Next, 2 weeks after this, the mice were implanted with a baseplate for Miniscope calcium imaging. Middle, maximum-intensity projection of an example mouse across one recording session, imaged using a Miniscope. Right, the spatial footprints of all recorded cells during that session, randomly colour coded. Each mouse was run one at a time for this experiment. Scale bars, 200 μm. b, Example of 24 concatenated calcium imaging offline sessions. Top, the sleep state across all the calcium imaging recordings. Bottom, the whole-population mean activity, the aversive ensemble mean activity, the overlap ensemble mean activity and the neural ensemble mean activity. The dotted grey lines represent the boundaries between each offline recording. c, Ensemble co-bursting across sleep states. Left, wake high-shock mice had higher co-bursting of overlap × neutral than overlap × aversive (t₄ = 4.94, P = 0.016) while low-shock mice had no difference in co-bursting between these ensembles (t₃ = 1.20, P = 0.32). Middle, for NREM, there was no difference in high-shock (t₄ = 0.53, P = 0.66) or low-shock (t₃ = −0.49, P = 0.66) co-bursting. Right, for REM, there was no difference in high-shock (t₄ = 1.04, P = 0.63) or low-shock (t₃ = −0.53, P = 0.63) co-bursting. n = 4 (low-shock) and n = 5 (high-shock) mice. Error bars indicate s.e.m.