Expression of a receptor protein has, for the first time, been definitively correlated with sensitivity to a particular odorant. This receptor, expressed in the nematode Caenorhabditis elegans, appears to be distinct from the putative vertebrate odorant receptors.

The odorant partition coefficient is a physicochemical property that has been shown to dramatically influence odorant deposition patterns in the mammalian nose, leading to a chromatographic separation of odorants along the sensory epithelium. It is unknown whether a similar phenomenon occurs in fish. Here we utilize molecular dynamics simulations, based on a simplified molecular model of olfact...

In mammals, smell is mediated by odorant receptors expressed by sensory neurons in the nose. These specialized receptors are found both on olfactory sensory neurons' cilia and axon terminals. Although the primary function of ciliary odorant receptors is to detect odorants, their axonal role remains unclear but is thought to involve axon guidance. This review discusses findings that show axonal ...

Early sensory experience shapes the anatomy and function of sensory circuits. In the mouse olfactory bulb (OB), prenatal and early postnatal odorant exposure through odorized food (food/odorant pairing) not only increases the volume of activated glomeruli but also increases the number of mitral and tufted cells (M/TCs) connected to activated glomeruli. Given the importance of M/TCs in OB output...

A new study has found that when a shark turns towards an odor, its directional decision is based on inter-nostril differences in odorant time of arrival, rather than on inter-nostril differences in odorant concentration.

Since the emergence of the first living cells, survival has hinged on the ability to detect and localize chemicals in the environment. Modern animal species ranging from insects to mammals express large odorant receptor repertoires to detect the structurally diverse array of volatile molecules important for survival. Despite the essential nature of chemical detection, there is surprising divers...

For humans, the localization of an odorant seems only possible if the odorant also stimulates the trigeminal nerve. There is, however, some evidence that active sniffing may affect this ability and facilitate the localization of pure odorants. Therefore, we tested the ability of 40 subjects to localize a pure odorant and a mixed olfactory/trigeminal stimulus under 2 stimulation conditions: eith...