1 1 Symposium Chemosensory Receptors Satellite DEVELOPMENT ...

257 Poster Central Olfaction and Chemical EcologyDIFFERENCES IN ODOR RESPONSES BETWEEN ANTERIORAND POSTERIOR PIRIFORM CORTEXIllig K.R. 1 , Kay R. 1 1 Psychology, University of Virginia,Charlottesville, VASingle pyramidal cells in piriform cortex respond to a large numberof structurally dissimlar odors, can distinguish between highly similarodorant compounds, and develop responses to non-olfactorycomponents of an odor-guided behavioral task. Together with observedanatomical features (e.g., Illig, 2005, J. Comp. Neurol. 488: 224-231),such complexity of responding suggests an information processingscheme in piriform cortex that combines convergent information fromthe olfactory bulb, amygdala and prefrontal cortex. To gain a betterunderstanding of these processes, we recorded responses of singleneurons in the anterior (APC) and posterior (PPC) piriform cortex to abroad range of structurally varied odorants. Of particular interest wasthe degree to which responses in these two areas differed, given theirdifferences in anatomical and functional organization. Results indicatethat APC cells display selectivity for one or two odors within an odorclass (µ = 1.37 odors), as shown previously. Interestingly, single cellsdisplayed such selectivity for multiple classes of odors (e.g., aldehydesand ketones), and such responses were related in complex ways toodorant structures. Results in PPC include evidence for an active,dynamic tuning of odor specificity within an odor trial, and apreferrential response by individual cells for multiple distinct odorswithin an odor class. Neither of these response characteristics werefound in APC. Taken together, these results point to separate,complimentary processing of odor information in APC and PPC.Supported by NIH Grant 05557 from NIDCD (KRI)258 Poster Central Olfaction and Chemical EcologyEXPERIENCE-DEPENDENT ADAPTATION OF SENSORYSYNAPSES IN THE OLFACTORY BULBTyler W.J. 1 , Murthy V.N. 1 1 Molecular & Cellular Biology, HarvardUniversity, Cambridge, MAExperience-dependent changes in neural circuits have traditionallybeen investigated in brain regions several synapses downstream of thesensory organ. Whether sensory experience can alter peripheral sensorysynapses remains largely unknown. In many animals, including rodents,synaptic processing of odor information initially occurs in glomeruli ofthe olfactory bulb. Here, we find that unilateral naris occlusion inneonatal rats results in the strengthening of primary synapses made byolfactory sensory neurons. Sensory information continues to beamplified through the circuit in deprived animals, as second-orderexcitatory synapses between neurons in the glomerular region were alsofound to be stronger. The increase in synaptic strength, triggered bysensory deprivation, is mediated by coordinated changes in both preandpostsynaptic properties. Our observations demonstrate that sensoryexperience can modify synaptic strength at the very first site ofinformation transfer between the environment and an organism. Thismodification may possibly serve as a mechanism for homeostatic gaincontrol in odor processing. Support: NIH and Klingenstein Fund.259 Poster Central Olfaction and Chemical EcologyTRANSIENT BETA-FREQUENCY SPIKING COUPLINGOLFACTORY AND MOTOR SITES DURING OLFACTORY S+RECOGNITIONHermer-Vazquez L. 1 , Hermer-Vazquez R. 1 1 Psychology, University ofFlorida, Gainesville, FLIn previous work, we demonstrated that olfactory and motor brainregions display synchronous, transient (