It has long been established that men and women have many differences. A study adds another item on the list, saying the ladies have better noses than the gents.

Researchers from the University of São Paulo, the Albert Einstein Hospital (also in São Paulo), and the University of California came together to explore the intricacies of the brain's olfactory region in men and women. Previous studies have investigated the biologies of olfactory sensitivity before using imaging methods but results have been controversial.

The researchers wanted more objective results and so turned to a more reliable technique, identifying the number of cells in a certain part of the brain instead of simply capturing images. Using the isotropic fractionator developed by a team from the Federal University of Rio de Janeiro, the researchers, led by Professor Roberto Lent from the National Institute of Translational Neuroscience and Federal University of Rio de Janeiro's Institute of Biomedical Sciences, examined the brains of 11 women and seven men, all over 55 years old at the time of their death.

By counting the number of cells found in the olfactory bulbs of the brains, the researchers discovered that women, on average, have 43 percent more cells in their olfactory bulbs than men. Counting each neuron specifically, the discrepancy in numbers between men and women was almost 50 percent.

"Generally speaking, larger brains with larger numbers of neurons correlate with the functional complexity provided by these brains. Thus, it makes sense to think that more neurons in the female olfactory bulbs would provide women with higher olfactory sensitivity," explained Lent.

Because cells aren't usually added later in life, this suggests that women are born with more olfactory bulb cells to begin with. What's not clear is why women are pre-wired with the ability, although some are of the belief it has to do with reproductive behaviors like kin recognition and pair bonding.

Titled "Sexual Dimorphism in the Human Olfactory Bulb: Females Have More Neurons and Glial Cells than Males," the study was published in the journal PLOS One. Study authors include: Roberto Lent, Wilson Jacob-Filho, Carlos A. Pasqualucci, Lea T. Grinberg, Claudia K. Suemoto, Jose M. Farfel, Renata E. P. Leite, Ana T. L. Alho, Glaucia B. Santos, Lays M. Oliveira, Renan A. Coutinho, Raquel M. Santos, and Ana V. Oliveira-Pinto.

Funding support was provided by: Conselho Nacional de Desenvolvimento Científico e Tecnológico, Instituto Nacional de Ciência e Tecnologia em Neurociência Translacional, Fundação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, and Fundação de Amparo à Pesquisa do Estado de São Paulo.

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