G. A. Ascoli, Petilla terminology: nomenclature of features of GABAergic interneurons of the cerebral cortex, Nat. Rev. Neurosci, vol.9, pp.557-568, 2008.
URL : https://hal.archives-ouvertes.fr/hal-00292588

A. Kepecs and G. Fishell, Interneuron cell types are fit to function, Nature, vol.505, pp.318-326, 2014.

D. Mi, Early emergence of cortical interneuron diversity in the mouse embryo, Science, vol.360, pp.81-85, 2018.

C. Mayer, Developmental diversification of cortical inhibitory interneurons, Nature, vol.555, pp.457-462, 2018.

S. J. Butt, The temporal and spatial origins of cortical interneurons predict their physiological subtype, Neuron, vol.48, pp.591-604, 2005.

L. Tricoire, A blueprint for the spatiotemporal origins of mouse hippocampal interneuron diversity, J. Neurosci, vol.31, pp.10948-10970, 2011.

M. Fogarty, Spatial genetic patterning of the embryonic neuroepithelium generates GABAergic interneuron diversity in the adult cortex, J. Neurosci, vol.27, pp.10935-10946, 2007.

M. Inan, J. Welagen, and S. A. Anderson, Spatial and temporal bias in the mitotic origins of somatostatin-and parvalbumin-expressing interneuron subgroups and the chandelier subtype in the medial ganglionic eminence, Cereb. Cortex, vol.22, pp.820-827, 2012.

H. Taniguchi, J. Lu, and Z. J. Huang, The spatial and temporal origin of chandelier cells in mouse neocortex, Science, vol.339, pp.70-74, 2013.

M. A. Picardo, Pioneer GABA cells comprise a subpopulation of hub neurons in the developing hippocampus, Neuron, vol.71, pp.695-709, 2011.
URL : https://hal.archives-ouvertes.fr/hal-01833210

P. Bonifazi, GABAergic hub neurons orchestrate synchrony in developing hippocampal networks, Science, vol.326, pp.1419-1424, 2009.
URL : https://hal.archives-ouvertes.fr/inserm-00483216

V. Villette, Development of early-born ?-aminobutyric acid hub neurons in mouse hippocampus from embryogenesis to adulthood, J. Comp. Neurol, vol.524, pp.2440-2461, 2016.
URL : https://hal.archives-ouvertes.fr/hal-01847021

L. Menendez-de-la-prida, S. Bolea, and J. V. Sanchez-andres, Origin of the synchronized network activity in the rabbit developing hippocampus, Eur. J. Neurosci, vol.10, pp.899-906, 1998.

K. D. Harris, Classes and continua of hippocampal CA1 inhibitory neurons revealed by single-cell transcriptomics, PLoS Biol, vol.16, p.2006387, 2018.

R. Batista-brito, J. Close, R. Machold, and G. Fishell, The distinct temporal origins of olfactory bulb interneuron subtypes, J. Neurosci, vol.28, pp.3966-3975, 2008.

S. A. Anderson, D. D. Eisenstat, L. Shi, and J. L. Rubenstein, Interneuron migration from basal forebrain to neocortex: dependence on Dlx genes, Science, vol.278, pp.474-476, 1997.

L. Mòdol, Spatial embryonic origin delineates GABAergic hub neurons driving network dynamics in the developing entorhinal cortex, Cereb. Cortex, vol.27, pp.1-13, 2017.

R. Tomioka, Demonstration of long-range GABAergic connections distributed throughout the mouse neocortex, Eur. J. Neurosci, vol.21, pp.1587-1600, 2005.

A. Sik, M. Penttonen, A. Ylinen, and G. Buzsáki, Hippocampal CA1 interneurons: an in vivo intracellular labeling study, J. Neurosci, vol.15, pp.6651-6665, 1995.

S. Jinno, Neuronal diversity in GABAergic long-range projections from the hippocampus, J. Neurosci, vol.27, pp.8790-8804, 2007.

J. S. Hu, Coup-TF1 and Coup-TF2 control subtype and laminar identity of MGE-derived neocortical interneurons, Development, vol.144, pp.2837-2851, 2017.

M. J. Bezaire and I. Soltesz, Quantitative assessment of CA1 local circuits: knowledge base for interneuron-pyramidal cell connectivity, Hippocampus, vol.23, pp.751-785, 2013.

D. Bianchi, On the mechanisms underlying the depolarization block in the spiking dynamics of CA1 pyramidal neurons, J. Comput. Neurosci, vol.33, pp.207-225, 2012.
URL : https://hal.archives-ouvertes.fr/hal-00854872

S. H. Lee, Parvalbumin-positive basket cells differentiate among hippocampal pyramidal cells, Neuron, vol.82, pp.1129-1144, 2014.

T. F. Freund and M. Antal, GABA-containing neurons in the septum control inhibitory interneurons in the hippocampus, Nature, vol.336, pp.170-173, 1988.

S. A. Bayer, Development of the hippocampal region in the rat I. Neurogenesis examined with 3H-thymidine autoradiography, J. Comp. Neurol, vol.190, pp.87-114, 1980.

V. Villette, Internally recurring hippocampal sequences as a population template of spatiotemporal information, Neuron, vol.88, pp.357-366, 2015.
URL : https://hal.archives-ouvertes.fr/hal-01848187

A. Malvache, S. Reichinnek, V. Villette, C. Haimerl, and R. Cossart, Awake hippocampal reactivations project onto othrogonal neuronal assemblies, Science, vol.353, pp.1280-1283, 2016.

X. Li, P. Somogyi, A. Ylinen, and G. Buzsáki, The hippocampal CA3 network: an in vivo intracellular labeling study, J. Comp. Neurol, vol.339, pp.181-208, 1994.

O. Garaschuk, E. Hanse, and A. Konnerth, Developmental profile and synaptic origin of early network oscillations in the CA1 region of rat neonatal hippocampus, J. Physiol, vol.507, pp.219-236, 1998.

X. Leinekugel, Correlated bursts of activity in the neonatal hippocampus in vivo, Science, vol.296, pp.2049-2052, 2002.

G. Buzsáki, Hippocampal sharp wave-ripple: a cognitive biomarker for episodic memory and planning, Hippocampus, vol.25, pp.1073-1188, 2015.

A. Oliva, A. Fernández-ruiz, G. Buzsáki, and A. Berényi, Role of hippocampal CA2 region in triggering sharp-wave ripples, Neuron, vol.91, pp.1342-1355, 2016.

Y. Deguchi, F. Donato, I. Galimberti, E. Cabuy, and P. Caroni, Temporally matched subpopulations of selectively interconnected principal neurons in the hippocampus, Nat. Neurosci, vol.14, pp.495-504, 2011.

M. Valero, Determinants of different deep and superficial CA1 pyramidal cell dynamics during sharp-wave ripples, Nat. Neurosci, vol.18, pp.1281-1290, 2015.

J. Angevine, Time of neuron origin in the hippocampal region, Exp. Neurol, vol.11, pp.1-39, 1965.

V. T. Takács, T. F. Freund, and A. I. Gulyás, Types and synaptic connections of hippocampal inhibitory neurons reciprocally connected with the medial septum, Eur. J. Neurosci, vol.28, pp.148-164, 2008.

L. Katona, Sleep and movement differentiates actions of two types of somatostatin-expressing GABAergic interneuron in rat hippocampus, Neuron, vol.82, pp.872-886, 2014.

D. Lapray, Behavior-dependent specialization of identified hippocampal interneurons, Nat. Neurosci, vol.15, pp.1265-1271, 2012.

T. J. Viney, Network state-dependent inhibition of identified hippocampal CA3 axo-axonic cells in vivo, Nat. Neurosci, vol.16, pp.1802-1811, 2013.

L. Katona, Behavior-dependent activity patterns of GABAergic longrange projecting neurons in the rat hippocampus, Hippocampus, vol.27, pp.359-377, 2017.

C. Wick, Z. Tetzlaff, M. R. Krook-magnuson, and E. , Novel long-range inhibitory nNOS-expressing hippocampal cells, Elife, vol.8, p.46816, 2019.

L. Save, A. Baude, and R. Cossart, Temporal embryonic origin critically determines cellular physiology in the dentate gyrus, Cereb. Cortex, vol.29, pp.2639-2652, 2018.
URL : https://hal.archives-ouvertes.fr/hal-01963582

T. Jarsky, R. Mady, B. Kennedy, and N. Spruston, Distribution of bursting neurons in the CA1 region and the subiculum of the rat hippocampus, J. Comp. Neurol, vol.506, pp.535-547, 2008.

A. Caputi, S. Melzer, M. Michael, and H. Monyer, The long and short of GABAergic neurons, Curr. Opin. Neurobiol, vol.23, pp.179-186, 2013.

V. Crépel, A parturition-associated nonsynaptic coherent activity pattern in the developing hippocampus, Neuron, vol.54, pp.105-120, 2007.

S. Royer, Control of timing, rate and bursts of hippocampal place cells by dendritic and somatic inhibition, Nat. Neurosci, vol.15, pp.769-775, 2012.

T. Geiller, M. Fattahi, J. Choi, and S. Royer, Place cells are more strongly tied to landmarks in deep than in superficial CA1, Nat. Commun, vol.8, p.14531, 2017.

A. Giovannucci, CaImAn an open source tool for scalable calcium imaging data analysis, Elife, vol.8, p.38173, 2019.
URL : https://hal.archives-ouvertes.fr/hal-01812108

E. A. Pnevmatikakis and A. Giovannucci, NoRMCorre: an online algorithm for piecewise rigid motion correction of calcium imaging data, J. Neurosci. Methods, vol.291, pp.83-94, 2017.

E. A. Pnevmatikakis, Simultaneous denoising, deconvolution, and demixing of calcium imaging data, Neuron, vol.89, p.299, 2016.

E. A. Pnevmatikakis, J. Merel, A. Pakman, and L. Paninski, Bayesian spike inference from calcium imaging data, Conference Record-Asilomar Conference on Signals, 2013.

J. T. Vogelstein, Fast non-negative deconvolution for spike train inference from population calcium imaging, Journal of Neurophysiology, vol.104, pp.3691-3704, 2010.

V. Lopes-dos-santos, S. Ribeiro, and A. B. Tort, Detecting cell assemblies in large neuronal populations, J. Neurosci. Methods, vol.220, pp.149-166, 2013.

T. Klausberger, Spike timing of dendrite-targeting bistratified cells during hippocampal network oscillations in vivo, Nat. Neurosci, vol.7, pp.41-47, 2004.

, assembly detection code and useful discussions

R. Khazipov, T. Marissal, and R. Boyce, This work was supported by the European Research Council under the European Union's FP7 and Horizon 2020 research and innovation program (grant No. 646925) and by the Bettencourt-Schueller Foundation (Coup d'Elan). M.B. was supported by the Fyssen Foundation, the Fondation pour la Recherche Medicale (grant No. SPF20170938593), and by the European Union (Marie Sk?odowska-Curie individual fellowship, grant No. 794861-IF-2017). D.A. was supported by an A*MIDEX grant (grant No. ANR-11-IDEX-0001-02) and by the I-Site Paris Seine Excellence Initiative (grant No, T.Tr. was supported by The French National Research Agency