The multiple roles of Broca's discovery in the development of the modern neurosciences.

Using the classical clinico-anatomical correlation method of the French clinical school, Paul Broca confirmed the localization of "language" in the frontal lobe. He actually discovered the lateralization of language in the left hemisphere. These contributions eventually led to the demise of the older concept of the "sensorium commune," because Broca's ideas implied the presence of motor functions in the hemispheres. Although Broca worked within the theoretical motif of the "faculty" psychology, the reflex-oriented "associationist" psychology soon became the predominant theoretical framework of localization, because it accommodated the motor aspect of hemispheric function. Since Broca's time, the study of the biology of language has proceeded along two parallel but sometimes separate lines in the experimental and clinical traditions.