In sum, Radsink ripple coactivity was stably aligned with recent waking motifs throughout post-exploration sleep. LMsink ripple coactivity initially reflected prior motifs but gradually drifted toward recent motifs, eventually reaching levels comparable to Radsink ripples.
(9/11)

Radsink ripples consistently aligned with recently acquired motifs and stayed stable throughout sleep. LMsink ripples expressed prior motifs but gradually disengaged from them, drifting toward recent motifs.
(8/11)

Looking at CA1 sublayers, both deep and superficial principal cells reactivated their waking theta coactivity during Radsink ripples. In contrast, during LMsink ripples only deep CA1 cells showed significant reactivation.
(7/11)

We then asked how ripple types structure coactivity motifs in CA1. LMsink ripples contained sparse, low dimensional motifs that acted as a core. During Radsink ripples these motifs reappeared with additional neurons, forming denser, composite patterns.
(6/11)

CA1 and CA3 principal cells fired at higher rates during Radsink ripples than during LMsink ripples. The timing of their responses also differed across types and aligned with current sinks in radiatum, lacunosum moleculare, and DG molecular layers.
(5/11)

Next, we asked how ripple types engage neuronal populations. Using tetrode recordings from CA1 and CA3, we classified ripple types directly from LFP traces with our open source tool. The code is available here; feel free to check it out and use it in your own work:
🔗 github.com/mcastelli98/...

To relate ripple types to sleep dynamics, we examined their distribution across cortical up and down states, inferred from DG activity. The proportion of LMsink ripples was higher in up states, suggesting cortical inputs bias ripple profiles.
(3/11)

To look at the currents driving ripples, we used current source density (CSD). The average showed the expected sink in CA1 radiatum, but individual ripples differed. We consistently found two types, Radsink and LMsink, differing in frequency and waveform.
(2/11)

I’m pleased to share our new paper, “Hippocampal ripple diversity organizes neuronal reactivation dynamics in the offline brain”, out in @cp-neuron.bsky.social !

With @vitorlds.bsky.social and David Dupret, we show that diversity in ripple current profiles shapes reactivation dynamics

Check out my preprint on hippocampal ripple diversity, with @vitorlds.bsky.social and David Dupret at the MRC BNDU, where we reveal that distinct CA1 laminar profiles of ripples are associated with different reactivation dynamics: www.biorxiv.org/content/10.1...