Humans are the only species in which asymmetric motor behavior is preponderant: 90% of people prefer to use their right hand and 10% their left hand. This motor behavior is “cross-lateralized”: when using the right hand, the dominant left hemisphere is activated. Along with motor behavior, language is one of the most lateralized functions of the human body: the networks of brain areas controlling language are located asymmetrically in the brain’s left or right hemisphere. Many studies have shown that the left hemisphere is dominant for language in 90% of cases, as it is for motor behavior.

Are the 10% of people who are left-handed and of those whose language is located in the brain’s right hemisphere the same? Is the location of language areas in the brain correlated to handedness? To answer these questions, researchers from the Groupe d’Imagerie Neurofonctionnelle recruited a large sample of participants (297) including numerous left-handed subjects (153). Whereas most other studies only relate to right-handers (a
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