RT Journal Article
SR Electronic
T1 Monosynaptic and Polysynaptic Feed-Forward Inputs to Mitral Cells from Olfactory Sensory Neurons
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 8722
OP 8729
DO 10.1523/JNEUROSCI.0527-11.2011
VO 31
IS 24
A1 Najac, Marion
A1 De Saint Jan, Didier
A1 Reguero, Leire
A1 Grandes, Pedro
A1 Charpak, Serge
YR 2011
UL http://www.jneurosci.org/content/31/24/8722.abstract
AB Olfactory sensory neurons (OSNs) expressing the same odorant receptor converge in specific glomeruli where they transmit olfactory information to mitral cells. Surprisingly, synaptic mechanisms underlying mitral cell activation are still controversial. Using patch-clamp recordings in mouse olfactory bulb slices, we demonstrate that stimulation of OSNs produces a biphasic postsynaptic excitatory response in mitral cells. The response was initiated by a fast and graded monosynaptic input from OSNs and followed by a slower component of feedforward excitation, involving dendro-dendritic interactions between external tufted, tufted and other mitral cells. The mitral cell response occasionally lacked the fast OSN input when few afferent fibers were stimulated. We also show that OSN stimulation triggers a strong and slow feedforward inhibition that shapes the feedforward excitation but leaves unaffected the monosynaptic component. These results confirm the existence of direct OSN to mitral cells synapses but also emphasize the prominence of intraglomerular feedforward pathways in the mitral cell response.