Abstract: Series 101, Lecture 7
The Harvey Lectures Series 101 (2005—2006)
Lecture #7: Thursday, May 18, 2006 — Time and Location
Unraveling Smell
Linda B Buck, PhD
Investigator, Howard Hughes Medical Institute
Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center
Seattle, Washington
Mammals can perceive a vast array of odor chemicals in the external world. We found that odor detection in the nose is mediated by ~1000 odorant receptors (ORs). The ORs are used combinatorially to encode odor identities, allowing discrimination of a multitude of odorants. We have asked how the nervous system translates these combinatorial codes into odor perceptions. We found that each sensory neuron in the nose expresses a single OR gene. Neurons with different ORs are randomly interspersed in the nose, but their axons synapse in OR-specific glomeruli in the brain's olfactory bulb, creating a stereotyped map of OR inputs. We discovered another stereotyped map of OR inputs at the next level of the olfactory system, the olfactory cortex, but here inputs from different ORs partially overlap. Moreover, single cortical neurons receive multiple different OR inputs, potentially allowing integration of the components of an odorant's combinatorial receptor code, and thereby a first step in the reconstruction of an odor image from its deconstructed features.