Specific anosmia in humans and animals: Environmental and genetic influences

Abstract

Olfaction plays a very important role across the lifespan of most mammalian species, including humans. Being the oldest, chemical communication is one of the least understood forms of communication due in part to the difficulty of detecting and measuring the chemicals in a sample. The ability to detect chemicals in the environment serves many functions. Individuals with specific anosmia, or “odor blindness”, have significantly increased olfactory thresholds to particular odorants though they show normal general olfactory acuity. Hereby we review research on specific anosmia in humans, factors that may affect individual variation in olfaction as well as animal models of specific anosmia. Variability in sensitivity to odorants is influenced by genotype, age, gender, individual olfactory experience and environmental cues. Large data pile from human and animal studies suggests that not all factors are determined yet. The possibility of induction of olfactory sensitivity to biologically relevant chemical cues is discussed. Olfactory plasticity determines the adaptability of the species to the environment. Mechanisms that underlie the induction of sensitivity to the odorants still to be elucidated.