TY - JOUR T1 - A pool of postnatally-generated interneurons persists in an immature stage in the olfactory bulb JF - The Journal of Neuroscience JO - J. Neurosci. DO - 10.1523/JNEUROSCI.1216-18.2018 SP - 1216-18 AU - Nuria Benito AU - Elodie Gaborieau AU - Alvaro Sanz Diez AU - Seher Kosar AU - Louis Foucault AU - Olivier Raineteau AU - Didier De Saint Jan Y1 - 2018/10/03 UR - http://www.jneurosci.org/content/early/2018/10/03/JNEUROSCI.1216-18.2018.abstract N2 - Calretinin (CR)-expressing periglomerular (PG) cells are the most abundant interneurons in the glomerular layer of the olfactory bulb. They are predominately generated postnatally from the septal and dorsal sub-ventricular zones that continue producing them well into adulthood. Yet, little is known about their properties and functions. Using transgenic approaches and patch-clamp recording in mice of both sexes we show that CR(+) PG cells of both septal and dorsal origin have homogenous morphological and electrophysiological properties. However, unlike other PG cells, these axonless neurons express a surprisingly small repertoire of voltage-activated channels and do not fire or fire at most a single and often small action potential. Moreover, they are not innervated by olfactory sensory neurons and receive little synaptic inputs from mitral or tufted cells at excitatory synapses where NMDA receptors predominate. These membrane and synaptic properties, that resemble those of newborn immature neurons not yet integrated in the network, persist over time and limit the recruitment of CR(+) PG cells by afferent inputs that strongly drive local network activity. Together, our results show that postnatally-generated CR(+) PG cells continuously supply a large pool of neurons with unconventional properties. These data also question the contribution of CR(+) PG cells in olfactory bulb computation.Significance statementCalretinin-expressing PG cells are by far the most abundant interneurons in the glomerular layer of the olfactory bulb. They are continuously produced during postnatal life, including adulthood, from neural stem cells located in the subventricular zones. Surprisingly, unlike other postnatally-generated newborn neurons that quickly integrate into pre-existing olfactory bulb networks, calretinin-expressing PG cells retain immature properties that limit their recruitment in local network activity for weeks, if not months, as if they would never fully mature. The function of this so far unsuspected pool of latent neurons is still unknown. ER -