Pioneer GABA Cells Comprise a Subpopulation of Hub Neurons in the Developing Hippocampus

Michel A. Picardo (1) , Philippe Guigue (1) , Paolo Bonifazi (1) , Renata Batista-Brito , Camille Allene (2) , Alain Ribas (3) , Gord Fishell , Agnès Baude (4) , Rosa Cossart (1)

1 INMED - INSERM U1249 - Institut de Neurobiologie de la Méditerranée [Aix-Marseille Université]
2 ICM - Institut du Cerveau et de la Moëlle Epinière = Brain and Spine Institute
3 INSERM - Institut National de la Santé et de la Recherche Médicale
4 CRN2M - Centre de recherche en neurobiologie - neurophysiologie de Marseille

Connectivity in the developing hippocampus displays a functional organization particularly effective in supporting network synchronization, as it includes superconnected hub neurons. We have previously shown that hub network function is supported by a subpopulation of GABA neurons. However, it is unclear whether hub cells are only transiently present or later develop into distinctive subclasses of inter-neurons. These questions are difficult to assess given the heterogeneity of the GABA neurons and the poor early expression of markers. To circumvent this conundrum, we used ''genetic fate mapping'' that allows for the selective labeling of GABA neu-rons based on their place and time of origin. We show that early-generated GABA cells form a sub-population of hub neurons, characterized by an exceptionally widespread axonal arborization and the ability to single-handedly impact network dynamics when stimulated. Pioneer hub neurons remain into adulthood, when they acquire the classical markers of long-range projecting GABA neurons.

Domains: Life Sciences [q-bio]; Neurons and Cognition [q-bio.NC]; Life Sciences [q-bio]; Neurons and Cognition [q-bio.NC]; Neurobiology

Michel A. Picardo, Philippe Guigue, Paolo Bonifazi, Renata Batista-Brito, Camille Allene, et al.. Pioneer GABA Cells Comprise a Subpopulation of Hub Neurons in the Developing Hippocampus. Neuron, 2011, 71 (4), pp.695 - 709. ⟨10.1016/j.neuron.2011.06.018⟩. ⟨hal-01833210⟩