| Description |
Sensory input to the olfactory system begins with the binding of an odorant molecule to an olfactory receptor (OR) contained on the surface of an olfactory sensory neuron (OSN). Olfactory bulb (OB) glomeruli receive information from OSNs containing the same OR type and are thought to help process sensory input directed further upstream. Therefore, characterizing the responses and characteristics of ORs is essential to understand further odor processing. To explore these questions, the responses of dorsal mouse OB glomeruli to 185 odorants at near-threshold concentrations were recorded in vivo. Analysis of these data revealed that OR/OSN responses in these concentration regimes are extremely sparse and specific, and that ORs are narrowly tuned to one or a small range of chemically similar odors. In addition, certain glomeruli have been found to be identifiable across animals solely based on their approximate location and the odor to which they are most responsive. Glomeruli that are maximally sensitive to similar odors also cluster together across the dorsal OB surface, supporting the hypothesis of a chemotopic arrangement of glomeruli. We also characterized the response spectrum of the OR defined glomerulus olfr1377, which has yet to be characterized in vivo. Olfr1377 was found to be responsive to a range of acetophenone derivatives, including 4-methoxyacetophenone to which it was especially sensitive to at extremely low concentrations. |
