Robert Lindenberg & Heiner Fangerau - On the current use of the term “Broca’s area”

Introduction: Methodological advances in neuroscientific research prompted numerous studies on the anatomical localisation of language functions. As a principal reference, the term “Broca’s area” is often quoted. Referring to Broca’s original work, it was anatomically connected to the inferior frontal gyrus and functionally related to expressive speech function. Recently, the increase in spatial resolution of functional imaging tools yielded a fractionation of “Broca’s area”.
   Methods: Regarding the variable functional ascriptions and anatomical descriptions, we analysed the current use of the term in 542 articles published between 1994 and 2004. We performed a literal approach of given definitions complemented by functional and structural cluster analyses of 3D-imaging data.
   Results: The literal approach revealed that seventy-nine percent of the authors provided a definition of their use of “Broca’s area”. With regard to functional definitions, no consensus across studies became apparent. The spatial range of anatomical correlates varied considerably. Neither of the cluster analyses did support the hypothesis of functionally and anatomically distinct subdivisions.
   Conclusions: We conclude that bridging the gap between the anatomically based term “Broca’s area” and the increasing amount of its supposed sub-functions is arbitrary.