title: In vivo whole-cell recording of odor-evoked synaptic transmission in the rat olfactory bulb.
abstract: One of the first steps in the coding of olfactory information is the transformation of synaptic input to action potential firing in mitral and tufted (M/T) cells of the mammalian olfactory bulb. However, little is known regarding the synaptic mechanisms underlying this process in vivo. In this study, we examined odor-evoked response patterns of M/T and granule cells using whole-cell recording in anesthetized, freely breathing rats. We find that odor-evoked excitatory responses in M/T cells typically consist of bursts of action potentials coupled to the approximately 2 Hz respiration rhythm. Odor-evoked, rhythmic M/T cell excitation is reliable during odor presentation (2-4 sec); in contrast, both excitatory responses of granule cells and M/T cell lateral inhibition adapt quickly after the first respiration cycle in the presence of odorants. We also find that the amplitude and initial slope of odor-evoked synaptic excitation play an important role in regulating the timing of M/T cell spikes. Furthermore, differences in odor concentration alter the shape of odor-evoked excitatory synaptic responses, the latency of M/T cell spikes, and the timing of M/T cell lateral inhibition.
authors.affiliation: Department of Neuroscience, School of Medicine, University of California, San Diego, La Jolla, California 92093-0608, USA.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Cang
authors.forename: Jeffry S
authors.initials: JS
authors.lastname: Isaacson
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D008297:Male; D009475:Neurons, Afferent / Q000166:cytology / Q000502:physiology; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*