A major goal of my lab is understanding biological complexities. In the hippocampus, this manifests in terms of a variety of cell types and dedicated connectivity. Recently, we discovered that genetically- and anatomically-defined CA1 pyramidal cells differently engage in ongoing oscillations. Using in vivo recordings, we found that deep and superficial CA1 pyramidal cells participate distinctly during sharp-wave ripples associated to memory consolidation (Valero et al Nat Neu 2015). Using unsupervised clustering of ripple events, we next disclosed a mechanism for firing selectivity and its distorsion in the epileptic hippocampus (Valero et al. Neuron 2017). Our data support the idea of a strong regionalization of hippocampal function during basic processes underlying memory consolidation.