Paul Broca's historic cases: high resolution MR imaging of the brains of Leborgne and Lelong

Abstract

In 1861, the French surgeon, Pierre Paul Broca, described two patients who had lost the ability to speak after injury to the posterior inferior frontal gyrus of the brain. Since that time, an infinite number of clinical and functional imaging studies have relied on this brain-behaviour relationship as their anchor for the localization of speech functions. Clinical studies of Broca's aphasia often assume that the deficits in these patients are due entirely to dysfunction in Broca's area, thereby attributing all aspects of the disorder to this one brain region. Moreover, functional imaging studies often rely on activation in Broca's area as verification that tasks have successfully tapped speech centres. Despite these strong assumptions, the range of locations ascribed to Broca's area varies broadly across studies. In addition, recent findings with language-impaired patients have suggested that other regions also play a role in speech production, some of which are medial to the area originally described by Broca on the lateral surface of the brain. Given the historical significance of Broca's original patients and the increasing reliance on Broca's area as a major speech centre, we thought it important to re-inspect these brains to determine the precise location of their lesions as well as other possible areas of damage. Here we describe the results of high resolution magnetic resonance imaging of the preserved brains of Broca's two historic patients. We found that both patients' lesions extended significantly into medial regions of the brain, in addition to the surface lesions observed by Broca. Results also indicate inconsistencies between the area originally identified by Broca and what is now called Broca's area, a finding with significant ramifications for both lesion and functional neuroimaging studies of this well-known brain area.

Elevated Mean Diffusivity in the Left Hemisphere Superior Longitudinal Fasciculus in Autism Spectrum Disorders Increases with More Profound Language Impairment

“…14,15 Regarding language function, early reports established association of lesions in specific cortical anatomic locations in the left frontal lobe with clinically recognized symptoms, defined as aphasia. 16 With time, subcortical pathways, such as the SLF, particularly its subdivision, the AF, [17][18][19] were also shown to be involved in language function. 20 Identification of language tracts by DTI has been pursued for a long time, and the imaging technique gained high acceptance in the literature.…”

What Do Language Disorders Reveal about Brain–Language Relationships? From Classic Models to Network Approaches

“…This region later became known as Broca's area, although for many years, numerous reports were published that contradicted Broca's finding (see Dronkers, Plaisant, Iba-Zizen, & Cabanis, 2007). It was Broca's impression that his patients understood everything that was said to them, which is why he objected to Trousseau coining the term "aphasia" (or loss of language; Broca, 1864).…”

A common functional neural network for overt production of speech and gesture

“…In particular, one would predict that Broca's area, and more specifically the dorsal part of pars opercularis in the inferior frontal gyrus, also known as Brodmann area (BA) 44, might be crucial for the initiation and coordination of speech and gesture (Gentilucci & Dalla Volta, 2008). This area is known to play an essential role in language production and perception (Grodzinsky & Friederici, 2006), and lesions here are directly linked to language disorders, such as aphasia (Dronkers et al, 2007). BA 44 might be crucial for co-speech gesture production because it is engaged in higherlevel word retrieval and speech articulation (Eickhoff et al, 2009;Golfinopoulos et al, 2010;Hickok, 2012;Price et al, 2011).…”