Broca and Wernicke are dead, or moving past the classic model of language neurobiology

• Published in: Brain and language Vol. 162; pp. 60 - 71
• Main Authors: Tremblay, Pascale, Dick, Anthony Steven
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.11.2016; Academic Press
• Subjects: Arcuate fasciculus; Biology; Brain; Broca Area - anatomy & histology; Broca Area - physiology; Broca’s area; Connectome; Humans; Language; Language connectome; Language neurobiology; Models, Neurological; Nerve Net - physiology; Neurobiology - trends; Neurolinguistics; Reproducibility of Results; Wernicke Area - anatomy & histology; Wernicke Area - physiology; Wernicke’s area; Broca’s area; Wernicke’s area; Language neurobiology; Language connectome; Arcuate fasciculus
• ISSN: 0093-934X; 1090-2155; 1090-2155
• DOI: 10.1016/j.bandl.2016.08.004

•Despite being 150 years old, the Classic Model of language neurobiology is still used.•Our survey shows there are no consistent definitions of Broca’s and Wernicke’s area.•We review the contemporary literature on perisylvian fiber pathway connectivity.•We advocate for rejection of the Classic model and its terminology. With the advancement of cognitive neuroscience and neuropsychological research, the field of language neurobiology is at a cross-roads with respect to its framing theories. The central thesis of this article is that the major historical framing model, the Classic “Wernicke-Lichtheim-Geschwind” model, and associated terminology, is no longer adequate for contemporary investigations into the neurobiology of language. We argue that the Classic model (1) is based on an outdated brain anatomy; (2) does not adequately represent the distributed connectivity relevant for language, (3) offers a modular and “language centric” perspective, and (4) focuses on cortical structures, for the most part leaving out subcortical regions and relevant connections. To make our case, we discuss the issue of anatomical specificity with a focus on the contemporary usage of the terms “Broca’s and Wernicke’s area”, including results of a survey that was conducted within the language neurobiology community. We demonstrate that there is no consistent anatomical definition of “Broca’s and Wernicke’s Areas”, and propose to replace these terms with more precise anatomical definitions. We illustrate the distributed nature of the language connectome, which extends far beyond the single-pathway notion of arcuate fasciculus connectivity established in Geschwind’s version of the Classic Model. By illustrating the definitional confusion surrounding “Broca’s and Wernicke’s areas”, and by illustrating the difficulty integrating the emerging literature on perisylvian white matter connectivity into this model, we hope to expose the limits of the model, argue for its obsolescence, and suggest a path forward in defining a replacement.