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Mammalian cerebral architecture is bisexual

As a rule, the external genitals of vertebrates show clear differences, but the cerebral images of the genitals are projected on the same anatomical map. This is demonstrated by a current study.



Researchers headed by Michael Brecht, Professor of Systemic Neurobiology and Neural Computation at Humboldt University, Berlin (HU) and Bernstein Zentrum Berlin used physiological and anatomical methods to identify a distinctive representation of the genitals in the rat somatosensory cortex. Size, shape, and erect posture give the cortical penis representation a phallic appearance, pointing to a role in sexually aroused states. The researchers observed significant growth in the relative size of the genital region during puberty corresponding in line with a sexual function of genital cerebral cortex.

Tactile sensations are represented in the brain in the form of structured maps of the body surface. The largest such map in the mammalian brain is located in the so-called somatosensory cortex.

Genital representations in the cerebral cortex are sexually monomorphic

Despite considerable scientific interest, essential aspects of representation of the genitals in the somatosensory cortex have yet to be clarified. The external genitalia in mammals are characterized by pronounced sexual dimorphism and can change their size and shape during sexual arousal. In a new study, researchers at the HU and the Marine Biology Lab in Woods Hole succeeded in producing high-resolution maps of the genital region of the somatosensory cortex. The study demonstrates a striking identity of the cortical penis and clitoris input maps despite the pronounced sexual dimorphism of the external genitalia. Thus, the genital representations in the cerebral cortex are sexually monomorphic, that is they assume the same shape.

This high-resolution mapping suggests a deep homology of penis and clitoris representations in the brain. The results are in line with other findings supporting a fundamentally bisexual layout of the mammalian brain.

Figure: Lenschow at al.


Lenschow at al., 2015, Current Biology 26, 1-8
Print: January 11, 2016 © Elsevier Ltd All rights reserved

Lenschow C, Copley S, Gardiner JM, Talbot ZN, Vitenzon A, Brecht M (2015) Sexually Monomorphic Maps and Dimorphic Responses in Rat Genital Cortex. CurrBiol 26:1-8.

The article is available online

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Ibou Diop
Humboldt-Universität zu Berlin

Phone: +49 30 2093-2945


Prof. Dr. Michael Brecht
Humboldt-Universität zu Berlin
Bernstein Center for Computational Neuroscience Berlin

Phone: +49 30 2093-6772