TALK: Gain modulation and odor concentration invariance in the honey bee antennal lobe

MARACHLIAN EMILIANO; LOCATELLI FERNANDO; AYELEN NALLY

Congreso; ESITO 2019; 2019

A conserved principle of the olfactory system, inmost, if not all animals, is that each olfactory receptor interacts withdifferent odorant molecules and each odorant molecule interacts with differentreceptors. This broad receptive field of the receptors constitutes the basis ofa combinatorial code that allows animals to discriminate many more odorantsthan the actual number of receptor types that they express. A drawback is thathigh odorant concentrations recruit lower affinity receptors, which can giverise to the perception of qualitatively different odors. Several mechanismsthat allow animals to attenuate the effect of the concentration and recognizethe odors regardless of their intensity have been studied. Here we addressedthe contribution that signal-processing in the honey bee antennal lobe does tokeep odor representation relatively stable across concentrations. We describethe contribution that GABA-A and GABA-B receptors-dependent-inhibition plays interms of amplitude and temporal profiles of signals that convey odor informationfrom the antennal lobes to the mushroom bodies. GABA reduces the amplitude ofodor elicited signals and the number of glomeruli that are recruited. Using calciumimaging we analyzed the stability of odor-elicited-activity-patterns acrossconcentrations. GABA-A and GABA-B dependent inhibition modulates the signals inpartially overlapping concentration ranges and increases the correlation amongglomerular activity patterns elicited by different concentrations of the sameodor. The results were used to adjust parameters of a realistic computationalmodel of the antennal lobe. Interestingly, even though based onrather simplistic connectivity rules and interactions among cells solelymediated by GABA-A and GABA-B interactions, the AL model reproduced the keyfeatures of the AL response in relation to different concentrations.