Does topography matter? Predicting odor response maps and inhibitory interactions between glomeruli for the dorsal olfactory bulb
Our understanding about how the chemical world maps to neuronal activity in the olfactory bulb (OB) is still limited, as the chemical receptive fields of only few glomeruli have been characterized. To date the odor‐evoked response patterns in the OB can’t be predicted at glomerular resolution. We will combine in vivo opto‐ and electrophysiological experiments, optogenetics, behavioral testing, in silicio screening and modeling to obtain an as complete as possible representation of chemical space in the OB. First we will characterize the chemical receptive range of glomeruli on the dorsal surface of the OB. To identify individual glomeruli across animals we will compose a set of odorants to stimulate as many glomeruli as possible in diverse patterns. For these identified glomeruli we will generate extensive odorant response spectra by iterative virtual and physiological screening. The resulting data will be used to analyze and quantify the strength of chemotopic organization for different physico‐chemical properties. We will test whether temporal components of odorant responses in the OB such as response latency and decay rate can also be predicted from the odorant’s chemical structure. Moreover, we will examine the relation of odorant similarity on the chemical level, on the level of the physiological response maps in the OB and in perceived similarity using a behavioral discrimination assay. Finally we will explore the topographic organization of the OB on a functional level by relating odorant response spectra of dorsal OB glomeruli to the inhibitory connectivity between mitral cells innervating those glomeruli.