Activity-dependent adjustments of the inhibitory network in the olfactory bulb following early postnatal deprivation.
The first-order sensory relay for olfactory processing, the main olfactory bulb (MOB), retains the ability to acquire new interneurons throughout life. It is therefore a particularly appropriate region for studying the role of experience in sculpting neuronal networks. We found that nostril closure decreased the number of newborn granule cells in the MOB, the complexity of their dendritic arborization, and their spine density, without affecting the preexisting population of granule cells. Accordingly, the frequency of miniature synaptic inhibitory events received by mitral cells was reduced. However, due to a compensatory increase in newborn granule cell excitability, action potential-dependent GABA release was dramatically enhanced, thus counteracting the reduction in spine density and leading to an unaltered synchronization of mitral cell firing activity. Together, this study reveals a unique form of adaptive response brought about exclusively by the cohort of newborn cells and used to maintain normal functioning of the MOB.
Saghatelyan
Armen
A
Laboratory of Perception and Memory, Pasteur Institute, Centre National de la Recherche, Scientifique (URA 2182), 75015 Paris Cedex, France.
Roux
Pascal
P
Migliore
Michele
M
Rochefort
Christelle
C
Desmaisons
David
D
Charneau
Pierre
P
Shepherd
Gordon M
GM
Lledo
Pierre-Marie
PM
D000818:Animals; D009433:Neural Inhibition / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology / Q000254:growth & development*; D009831:Olfactory Mucosa / Q000294:innervation; D051381:Rats; D012683:Sensory Deprivation / Q000502:physiology*