"Broca's area" as a collective term?
Recent methodological advances prompted numerous neuroactivation studies on the anatomical localization of language functions. As a principal reference, the term "Broca's area" was anatomically connected to the inferior frontal gyrus and functionally related to expressive speech function. The increase in spatial resolution of functional imaging tools yielded a fractionation of "Broca's area". We analyzed the current use of the term with regard to the various functional ascriptions and anatomical descriptions. We followed a literal approach using the given definitions and complemented it by cluster analyses of imaging data. (1) The literal approach revealed that 79% of the authors provided a definition of their use of "Broca's area". The spatial range of anatomical correlates varied considerably. (2) Neither of the cluster analyses supported the hypothesis of functionally and anatomically distinct subdivisions. With regard to functional definitions, no consensus across studies became apparent. We conclude that bridging the gap between the anatomically based term "Broca's area" and the increasing amount of its supposed subfunctions is arbitrary.
Lindenberg
Robert
R
Department of Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany. Robert.Lindenberg@uni-duesseldorf.de
Fangerau
Heiner
H
Seitz
Rüdiger J
RJ
D016000:Cluster Analysis; D003952:Diagnostic Imaging; D005625:Frontal Lobe / Q000033:anatomy & histology*; D006801:Humans; D007802:Language; D014705:Verbal Behavior / Q000502:physiology