Brain response to putative pheromones in lesbian women

doi:10.1073/pnas.0600331103

Brain response to putative pheromones in lesbian women

*Department of Medicine, and
^†Stockholm Brain Institute, Department of Clinical Neuroscience, Karolinska University Hospital, Karolinska Institutet, 171 76 Stockholm, Sweden

Edited by Jan-Åke Gustafsson, Karolinska Institutet, Huddinge, Sweden, and approved March 11, 2006 (received for review January 13, 2006)

Abstract

The progesterone derivative 4,16-androstadien-3-one (AND) and the estrogen-like steroid estra-1,3,5(10),16-tetraen-3-ol (EST) are candidate compounds for human pheromones. In previous positron emission tomography studies, we found that smelling AND and EST activated regions primarily incorporating the sexually dimorphic nuclei of the anterior hypothalamus, that this activation was differentiated with respect to sex and compound, and that homosexual men processed AND congruently with heterosexual women rather than heterosexual men. These observations indicate involvement of the anterior hypothalamus in physiological processes related to sexual orientation in humans. We expand the information on this issue in the present study by performing identical positron emission tomography experiments on 12 lesbian women. In contrast to heterosexual women, lesbian women processed AND stimuli by the olfactory networks and not the anterior hypothalamus. Furthermore, when smelling EST, they partly shared activation of the anterior hypothalamus with heterosexual men. These data support our previous results about differentiated processing of pheromone-like stimuli in humans and further strengthen the notion of a coupling between hypothalamic neuronal circuits and sexual preferences.

Footnotes

^‡To whom correspondence should be addressed at:
Stockholm Brain Institute, Department of Clinical Neuroscience, Karolinska Institutet, Magnetic Resonance Centre, Karolinska Hospital, 171 76 Stockholm, Sweden.
E-mail: ivanka.savic-berglund{at}ki.se
Author contributions: I.S. designed research; H.B., P.L., and I.S. performed research; H.B. and I.S. analyzed data; and H.B. and I.S. wrote the paper.
Conflict of interest statement: No conflicts declared.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations:

Abbreviations:

HeM,

heterosexual men;

HeW,

heterosexual women;

HoM,

homosexual men;

AND,

4,16-androstadien-3-one;

EST,

estra-1,3,5(10),16-tetraen-3-ol;

OO,

ordinary odors;

AIR,

odorless air;

PET,

positron emission tomography;

rCBF,

regional cerebral blood flow;

SPM,

statistical parametric mapping;

VOI,

volume of interest.