Functional neuronal processing of body odors differs from that of similar common odors
Lundström JN, Boyle JA, Zatorre RJ, Jones-Gotman M.Department of Psychology, McGill University, Montreal, QC, H3A1B1, Canada. jlundstrom@monell.org
At the moment, the reason why most people can't be smelt by some people is wide open to theories. This seems to include 'classic' external body odor (armpit body odor), rather than just metabolic body odor (where it seems to be mostly the norm).
The olfactory system seems to be the least understood sense, and so no answers seem forthcoming soon. The main areas of theory would likely be around the olfactory system itself, or that some 'non-smellers' carry the same toxins in their circulating system themselves, and so there may not a wide enough 'detection gap'. Who knows ?
On a similar note, recent research by a group of Swedish scientists (psychologists) came up with the conclusion that the olfactory system 'learns' neural pathway patterns, and recognises 'friends' 'body odor' (presumably the non-detectable type ?) and feels safe, whereas new peoples 'body odor' stimulates fear (?)
Visual and auditory stimuli of high social and ecological importance are processed in the brain by specialized neuronal networks. To date, this has not been demonstrated for olfactory stimuli. By means of positron emission tomography, we sought to elucidate the neuronal substrates behind body odor perception to answer the question of whether the central processing of body odors differs from perceptually similar nonbody odors. Body odors were processed by a network that was distinctly separate from common odors, indicating a separation in the processing of odors based on their source. Smelling a friend's body odor activated regions previously seen for familiar stimuli, whereas smelling a stranger activated amygdala and insular regions akin to what has previously been demonstrated for fearful stimuli. The results provide evidence that social olfactory stimuli of high ecological relevance are processed by specialized neuronal networks similar to what has previously been demonstrated for auditory and visual stimuli.
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