Smelling without an olfactory bulb?
Smell is possibly the most enigmatic sense. We only recently became aware that our social communications and interactions are influenced by our sense of smell, training may improve the ability to smell again in people suffering from anosmia, and smell scientists across the globe are working hard to fully understand how smell perception actually works on the level of the brain. The olfactory bulb, located just below our eyes behind our nose, is assumed to play an important role in sending the information about smell molecules to our brains.
Yet, as should be the case, in science, more questions than answers arise with every new scientific study. Last week, Tali Weiss, Timna Soroka and colleagues from Noam Sobel’s lab located at the Weizman institute in Israel, published an article suggesting that about 0.6% of women have no olfactory bulb, yet their sense of smell is fully functional and intact. They came to realize this when they scanned two women as part of a control group for a different study, who reported to be able to smell normally, yet the scans showed no bulb at all. The below image, showing MRI scans from people with a fully functional sense of smell, with intact olfactory bulbs colored and two instances of absent olfactory bulbs highlighted, illustrates this finding.
(c) Sobel lab Weizman institute
In addition, by examining a large database of brain scans, they found more women who could smell, but who had no apparent olfactory bulb, a finding more likely in left-handed women than in right-handed women. The authors propose no less than 5 possible explanations for this finding. Future follow-up studies have to reveal which of these explanations, or perhaps even a sixth alternative explanation, is the most likely explanation. And what this can mean for our understanding of how our noses work, or why some people suffer from congenital anosmia, for example.