Becoming a new neuron in the adult olfactory bulb.
New neurons are continually recruited throughout adulthood in certain regions of the adult mammalian brain. How these cells mature and integrate into preexisting functional circuits remains unknown. Here we describe the physiological properties of newborn olfactory bulb interneurons at five different stages of their maturation in adult mice. Patch-clamp recordings were obtained from tangentially and radially migrating young neurons and from neurons in three subsequent maturation stages. Tangentially migrating neurons expressed extrasynaptic GABA(A) receptors and then AMPA receptors, before NMDA receptors appeared in radially migrating neurons. Spontaneous synaptic activity emerged soon after migration was complete, and spiking activity was the last characteristic to be acquired. This delayed excitability is unique to cells born in the adult and may protect circuits from uncontrolled neurotransmitter release and neural network disruption. Our results show that newly born cells recruited into the olfactory bulb become neurons, and a unique sequence of events leads to their functional integration.
Carleton
Alan
A
Pasteur Institute, Laboratory of Perception and Memory, CNRS UMR 2182, 25 Rue du Dr Roux, 75015 Paris, France.
Petreanu
Leopoldo T
LT
Lansford
Rusty
R
Alvarez-Buylla
Arturo
A
Lledo
Pierre-Marie
PM
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D009830:Olfactory Bulb / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology