Activation of the anterior cingulate gyrus by 'Green Odor': a positron emission tomography study in the monkey.
The equivalent mixture of cis-3-hexenol and trans-2-hexenal (hexenol/hexenal), 'green odor', is known to have a healing effect on the psychological damage caused by stress. Behavioral studies in humans and monkeys have revealed that hexenol/hexenal prevents the prolongation of reaction time caused by fatigue. In the present study, we investigated which brain regions are activated by the odor of hexenol/hexenal using positron emission tomography with alert monkeys. Regional cerebral blood flow (rCBF) in the prepyriform area (the primary olfactory cortex) was commonly increased by the passive application of odor: acetic acid, isoamylacetate or hexenol/hexenal. We observed rCBF increases in the orbitofrontal cortex (the secondary olfactory cortex) by these olfactory stimuli in two of three monkeys, and found no predominance of laterality of the activated hemisphere. Furthermore, rCBF increase in the cerebellum was observed in two of three monkeys, and the odor of acetic acid increased rCBF in the substantia innominata in all monkeys. In addition to these olfactory related regions, the anterior cingulate gyrus was activated by the odor of hexenol/hexenal. These findings suggest that the increase of rCBF in the anterior cingulate gyrus by the odor of hexenol/hexenal may contribute the healing effects of this mixture observed in the monkey.
Sasabe
Tetsuya
T
Department of Oral Physiology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan.
Kobayashi
Masayuki
M
Kondo
Yusuke
Y
Onoe
Hirotaka
H
Matsubara
So
S
Yamamoto
Shigeyuki
S
Tsukada
Hideo
H
Onoe
Kayo
K
Watabe
Hiroshi
H
Iida
Hidehiro
H
Kogo
Mikihiko
M
Sano
Kohta
K
Hatanaka
Akikazu
A
Sawada
Tohru
T
Watanabe
Yasuyoshi
Y
D000447:Aldehydes / Q000737:chemistry; D000818:Animals; D001931:Brain Mapping; D002531:Cerebellum / Q000502:physiology; D006179:Gyrus Cinguli / Q000098:blood supply / Q000502:physiology*; D000441:Hexanols / Q000737:chemistry; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D008297:Male; D009812:Odorants; D012903:Smell / Q000502:physiology*; D013377:Substantia Innominata / Q000502:physiology; D014055:Tomography, Emission-Computed
D000447:Aldehydes; D000441:Hexanols; C051918:3-hexen-1-ol; C051750:2-hexenal