Battle of the titans: Charcot and Brown-Séquard on cerebral localization.
OBJECTIVE
To examine the differing views of Jean-Martin Charcot and Charles Edouard Brown-Séquard-two celebrated neuroscientists of the nineteenth century-on cerebral localization as exemplified in their controversial debate of 1875 at the Société de Biologie in Paris.


BACKGROUND
As clinicopathologic correlations were developed in the mid and late nineteenth century, cerebral localization was a primary topic of debate at scientific, social, and religious levels. Charcot, representing an anatomic approach to research, and Brown-Séquard, representing a physiologic perspective, disagreed fundamentally on the importance of cerebral localization to normal behavior and neurologic illness.


METHODS
The minutes of the Société de Biologie meetings of 1875 and 1876, as well as primary archive documents from the Archives Nationales de l'Académie des Sciences and the Bibliothèque Charcot, were examined.


RESULTS
Charcot was a strong proponent of localization theory and relied on human pathologic material primarily from isolated cerebral hematomas to establish the role of the cortex and subcortical white matter fiber tracts to motor and sensory function. Brown-Séquard used his animal physiology experiments to argue that the brain was composed of complex networks and that isolated lesions had no direct bearing on the localization of cerebral function.


CONCLUSION
Although Charcot's simple and direct anatomic methods won the debate on this occasion, Brown-Séquard's prioritization of physiology and experimentalism became beacons of modern neurologic study at the close of the nineteenth century. Charcot's later failures in the study of hysteria can be viewed as attempts to mimic physiologic experiments in the manner of Brown-Séquard's scientific methods.