The ability to taste and smell is important for the survival of most animals, and in humans they play a key role in nutrition, helping us detect if food is spoiled and prevent food poisoning, as well as such as identifying toxic substances in the environment or a fire, for example.
In humans, the olfactory system consists of two channels of sensory information that comes from the olfactory epithelia found in the left and right nostrils, but now, a group of researchers led by the University of Pennsylvania (Philadelphia) and the Barrow Neurological Institute (Phoenix) in the United States has discovered that each of the nasal passages has its own sense of smell.
The authors of the study that reached this conclusion examined the neural processes underlying odor processing in the human olfactory system and how the brain handles information about odors coming from different nasal passages. Their findings have been published in an article in Current Biology, in which they explain that each nostril has its own sense of smell, recording a different representation of the odor information it contains.
Identify the smell and which nostril it came from
The research involved 10 individuals with intracranial depth electrodes in an odor identification task in which olfactory stimuli were administered to the left, right, or both nostrils via an olfactometer device designed to generate odors by control. By computer.
Gaining a deeper understanding of how humans perceive and identify odors may have broader implications for sensory neuroscience and cognitive science.
These people had to identify the odor and indicate which nostril it came from, and they obtained better results in detecting and identifying odors perceived through both nostrils compared to when they had received it through a single nostril, without it being observed. a significant efficiency preference between situations in which the olfactory stimuli had arrived through the left and right nostrils.
The identity of the odor could be decoded from oscillations in the brain’s piriform cortex – an area involved in the sense of smell – using neuronal activity recorded in an intracranial electroencephalogram. The researchers observed that odor identity was encoded at two distinct and temporally segregated epochs in the test involving both nostrils, suggesting that a separate odor interpretation occurs through each nostril.
Stimulating either nostril with the same odor elicited similar but distinguishable representations during their encodings. This suggests that while each nostril may identify a different odor as the same, there are subtle differences in how they perceive the odor. Odor representations were achieved faster in the two-nostril test, suggesting a possible computational advantage in stereo odor processing. Understanding these processes is essential to gaining a deeper understanding of how humans perceive and identify odors and may have broader implications for sensory neuroscience and cognitive science.
