Finally, left orbitofrontal cortex was more active in women than men, potentially in relation to women's well-documented advantage in odor identification. It is well known that the RHI is optimally evoked by a pleasant stroking (affective) touch, but what of an unpleasant (painful) stroking touch does hedonic valence matter To this aim, participants repeated the RHI while receiving different types of touch: pleasant, painful, and neutral. Active decisions about odor pleasantness induced specific left orbitofrontal cortex activation, implicating the role of this area in the conscious assessment of the emotional quality of odors. Unpleasant odors activated the left ventral insula in right-handers and the right ventral insula in left-handers, suggesting lateralized processing of emotional odors as a function of handedness. More extreme ratings were also associated with higher electrodermal amplitude, suggesting that activation stemmed more from emotional or hedonic intensity than valence, and that unpleasant odors induced more arousal than pleasant odors. The piriform-amygdala area and ventral insula were activated more for unpleasant than pleasant odors. Electrodermal and plethysmography responses were simultaneously recorded to control for covert, physiological manifestations of the emotional response. In the first run, subjects passively smelled odorants, whereas in the second run they rated degree of odor pleasantness or unpleasantness by using a “finger-span” technique that simulated a visual rating scale. Two functional runs were performed, with pleasant and unpleasant odors presented in different epochs. unpleasant), active hedonic judgments versus passive sensation of hedonically charged odors, handedness, and gender.

We collected functional magnetic resonance imaging data from 28 subjects to study this network as a function of odor hedonic valence (pleasant vs. Previous positron emission tomography studies of right-handed individuals show that the left orbitofrontal cortex is dominant during emotional processing of odors.

Hedonic valence