PROBING FUNCTIONALITY OF THE HUMAN VNO
Wyart C.J.1, Webster W.2, McClary A.3, Sobel N.3 1Psychology,
University of California, Berkeley, Berkeley, CA; 2Kaiser Medical,
Berkeley, CA; 3Neuroscience, University of California, Berkeley,
berkeley, CA
Mammalian pheromones influence behavior and/or hormonal state in
conspecifics, often through the vomeronasal organ (VNO). Human
putative pheromones have been identified, but whether human adults
have a functional VNO remains controversial. Here we test whether the
putative human VNO mediates the effects of smelling the putative
pheromone 4,16-androstadien-3-one (AND). Smelling AND influences
autonomic nervous system activity, endocrine state, and mood in
women. We set out to quantify these effects, and then ask whether we
could negate them by physically and chemically blocking the putative
VNO (VNOblock). 30 women are scheduled for three 2.5-hour-long
sessions separated by 28 days. In a double-blind study, VNOblock was
applied selectively before exposure to either AND or CONTROL.
Session order was counter balanced, and AND/CONTROL were
matched for intensity/pleasantness. This design allowed us to assess the
differential impact of VNOblock on the physiological, endocrine, and
psychological response to AND and CONTROL. To date, 31 women
have completed the first day of study, 12 have completed 2 days. A
limited pilot analysis of 7 subjects who were counterbalanced for days
ONE and TWO suggests a greater physiological response to AND than
CONTROL (F(1,69) = 10.3, p < 0.002), but no interaction with
VNOblock (F(1,69) = .8, p = 0.36). Although this points against
functionality of the human VNO, the power of this comparison is
minimal (n = 7). By Achems meeting time, all participants will have
completed all days, and we expect to be able to determine whether
blocking the putative human VNO influences the response to putative
human pheromones.
DIFFERENT CEREBRAL ACTIVATION PRODUCED BY A
PUTATIVE SOCIAL CHEMOSIGNAL AND PERCEPTUALLY
SIMILAR ODORANTS
Gerber J.C.1, Bensafi M.2, Husner A.3, Frasnelli J.4, Reden J.4, Hummel
T.4 1University of Dresden, Dresden, Germany; 2Neuroscience,
University of California, Berkeley, Berkeley, CA; 3ENT Department,
University of Basel, Basel, Switzerland; 4ENT, University of Dresden,
Dresden, Germany
Aim of this study was to compare cerebral activation produced by a
putative social chemosignal and perceptually similar odorants, namely
androstadienone, androstenone, and butanol. A computer-controlled
olfactometer was used for stimulus presentation (OM6b, Burghart
Instruments, Germany); 12 healthy female volunteers (mean age 24
years; 20 to 30 years) participated. The three odors were rated as
equally intense, and received similar hedonic ratings (n.s.). Subjects
were right-handed, normosmic and had no nasal pathology. They were
examined in a 1.5 Tesla MRI scanner (Siemens, Germany). Stimuli
were presented in blocks (30 s odorless air, 30 s odorant; 1 s stimulus
duration, 3 s ISI, randomized). Preliminary investigations showed
differences in cortical representation, pointing to a higher involvement
of limbic structures (cingulate cortex, amygdala) and orbitofronal cortex
for androstadienone. The data suggest that a putative social chemosignal
produces different patterns of activation compared to “normal” odors.