Sensory systems: Connecting olfaction

摘要

The mammalian -olfactory bulb (OB) contains parvalhumin-expressing (PV~+) GABAergic interneurons, but their functional roteinthis structure is poorly understood. Two new studies reveal that these interneuroris form extensive connections with mitral cells and tufted cells- the major output neurons of the OB- and have a role in odour * processing.To assess neural connectivity in the OB, Miyamichif Shlomai-Fuchs et al, used a rabies virus-mediated monosynaptic tracing system, in which the expression of virus-encoded green fluorescent protein (GFP) is used to determine presynaptic connections. Following infection of mitral cells and tufted cells, they identified a large population of broadly distributed GFP-expressing cells in the external plexiform layer (EPL) of the OB. These cells had star-like morphologies that resembled interneurons and expressed PV, suggesting that PV~+ interneurons are the main presynaptic partners of mitral and tufted cells in the EPL.