Right-nostril advantage for discrimination of odors

Abstract

Olfactory discrimination was tested with eight pairs of odors presented to each nostril of each subject. Ninety-nine subjects were tested; there were equal numbers of left-and right-handers, as well as both sexes. Detection thresholds for phenylethyl alcohol were measured separately in each nostril using a forced-choice staircase procedure. In addition, a verbal dichotic listening test known to be sensitive to language lateralization was administered. Results indicated that discrimination performance was significantly better when the stimuli were presented to the right nostril than when they were presented to the left, but no differences between the nostrils in detection thresholds were found. The right-nostril advantage did not vary as a function of sex or handedness, and did not bear any relation to language lateralization as measured via dichotic listening. The asymmetry for olfactory discrimination replicates an earlier study and is interpreted in terms of a possible specialization of function within the right cerebral hemisphere.

Odour identification in frontotemporal lobar degeneration

“…Our study does not allow clear conclusions regarding hemispheric lateralisation of olfactory processing. A preferential role for the right hemisphere in both the perceptual and semantic analysis of odours is supported by functional imaging evidence in normal subjects [9,12], and psychophysical evidence in normal subjects [28] and in patients with focal cerebral resections [15,17]. However, other evidence [7,10,11,13,18] argues against a simple serial transfer of olfactory information within or between hemispheres.…”

Olfactory lateralization in homing pigeons: a GPS study on birds released with unilateral olfactory inputs

“…Interestingly, a lateralization in favour of the right nostril has also been demonstrated in humans, particularly in evaluating odour intensity (Thuerauf et al, 2008) and in olfactory detection and discrimination (Kobal et al, 2000;Zatorre and Jones-Gotman, 1990).…”

Asymmetries of the human social brain in the visual, auditory and chemical modalities

“…However, many studies show that the right hemisphere appears to be involved more than the left in the recognition and evaluation of olfactory stimuli disregarding the side of nostril stimulation (Zucco & Tressoldi 1988;Zatorre & Jones-Gotman 1990;Zatorre et al 1992b;Zald & Pardo 2000;Dijksterhuis et al 2002), and the right OFC seems to have a special role in this circuitry. However, there are many aspects of olfactory lateralization that seem to strongly depend on the task accomplished or the stimuli used (Brand et al 2001;Royet & Plailly 2004): when subjects are exposed to strongly aversive stimuli, the activity of the OFC is stronger in the left hemisphere and a bilateral activation of the amygdala is observed (Zald & Pardo 1997;Anderson et al 2003).…”