Final Report Summary - ODORSPACE (Predicting odor perception from odorant structure and neural activity in the olfactory system)
Exactly one hundred years ago, Alexander Graham Bell asked: “Can you measure the difference between one kind of smell and another? It is very obvious that we have very many different kinds of smells, all the way from the odor of violets and roses up to asafetida. But until you can measure their likenesses and differences you can have no science of odor” With this challenge in mind, we have developed a metric approach to smell. We generated a metric that can be estimated for any molecule, where it serves to predict perception and neural activity across species. This effort culminated in an ability to answer Bell's question: rose and violet are similar to each other, and both are dissimilar from asafetida, yet violet is closer to asafetida than rose. This approach now allows a systematic probing of the neurobiology of olfaction. The process of answering this major question also brought us to several surprising solutions for questions we originally did not set out to answer. Most notable of these followed from our investigation of the role of sniffing behavior in formation of the olfactory percept. While investigating this issue, it dawned on us that sniffing is a sensory-motor feedback loop that is precisely controlled yet very robust in its neural organization. With this in mind, we hypothesized that sniffing would remain conserved following severe brain injury. After verifying this, we built a series of devices that allow paralyzed individuals to control external devices such as computers and electric wheelchairs with their nose. These devices have changed the lives of participants in our studies, and we hope they will soon become widely available.