title: Spiking patterns and their functional implications in the antennal lobe of the tobacco hornworm Manduca sexta.
abstract: Bursting as well as tonic firing patterns have been described in various sensory systems. In the olfactory system, spontaneous bursts have been observed in neurons distributed across several synaptic levels, from the periphery, to the olfactory bulb (OB) and to the olfactory cortex. Several in vitro studies indicate that spontaneous firing patterns may be viewed as "fingerprints" of different types of neurons that exhibit distinct functions in the OB. It is still not known, however, if and how neuronal burstiness is correlated with the coding of natural olfactory stimuli. We thus conducted an in vivo study to probe this question in the OB equivalent structure of insects, the antennal lobe (AL) of the tobacco hornworm Manduca sexta. We found that in the moth's AL, both projection (output) neurons (PNs) and local interneurons (LNs) are spontaneously active, but PNs tend to produce spike bursts while LNs fire more regularly. In addition, we found that the burstiness of PNs is correlated with the strength of their responses to odor stimulation--the more bursting the stronger their responses to odors. Moreover, the burstiness of PNs was also positively correlated with the spontaneous firing rate of these neurons, and pharmacological reduction of bursting resulted in a decrease of the neurons' responsiveness. These results suggest that neuronal burstiness reflects a physiological state of these neurons that is directly linked to their response characteristics.
authors: Department of Neuroscience, University of Arizona, Tucson, Arizona, United States of America. hlei@neurobio.arizona.edu
authors: Hong
authors: H
authors: Lei
authors: Carolina E
authors: CE
authors: Reisenman
authors: Caroline H
authors: CH
authors: Wilson
authors: Prasad
authors: P
authors: Gabbur
authors: John G
authors: JG
authors: Hildebrand
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D007395:Interneurons / Q000166:cytology / Q000187:drug effects; D008297:Male; D018402:Manduca / Q000166:cytology* / Q000502:physiology*; D019581:Neuropil / Q000166:cytology* / Q000187:drug effects; D009812:Odorants
chemical_list: C017069:bicuculline methiodide; D001640:Bicuculline