Through functional magnetic resonance imaging, or fMRI, scientists from the University of Wisconsin-Madison and collaborating institutions for the first time peered into the brains of fully conscious nonhuman primates to learn what's really on their minds when it comes to sex. The research appears in the February 2004 issue of the Journal of Magnetic Resonance Imaging.

Common marmosets, like humans, live in family groups and have to make careful choices when confronted with the scent of an attractive female, a team of marmoset experts led by Charles T. Snowdon, UW-Madison professor of psychology, discovered.

"We were surprised to observe high levels of neural activity in areas of the brain important for decision-making, as well as in purely sexual arousal areas, in response to olfactory cues," Snowdon says. "Lighting up far more brightly than we expected were areas associated with decision-making and memory, emotional processing and reward, and cognitive control."

The marmoset fMRI findings add strong weight to the mounting evidence that, when faced with a novel, sexually attractive and receptive female, males even in monogamous species aren't necessarily just acting on some primal urge to procreate, without a second thought. Rather, they exhibit highly organized, complex neural processes.

"This is the first time anyone has imaged an awake nonhuman primate in response to emotionally arousing stimuli; it is also the first link between external sexual odors and the internal sexual arousal system," Snowdon says. "This opens up a whole new field of research possibilities."

The marmoset data corresponded surprisingly close to human fMRI studies, the scientists found. "The benefit of the nonhuman primate model is that we can control and know the devel
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Contact: Charles Snowdon
snowdon@wisc.edu
608-262-3974
University of Wisconsin-Madison
29-Jan-2004