Re-establishing Broca's initial findings.
The importance of the left inferior pre-frontal cortex (LIPC) for speech production was first popularized by Paul Broca, providing a cornerstone of behavioral neurology and laying the foundation for future research examining brain-behavior relationships. Although Broca's findings were rigorously challenged, comprehensive contradictory evidence was not published until 130years later. This evidence suggested that damage to left anterior insula was actually the best predictor of motor speech impairment. Using high-resolution structural magnetic resonance imaging (MRI) in patients with chronic stroke, we reveal that LIPC involvement more accurately predicts acquired motor speech impairment than insula damage. Perfusion-weighted MRI provides complementary evidence, highlighting how damage to left inferior pre-frontal gyrus often includes insula involvement, and vice versa. Our findings suggest that Broca's initial conclusions associating acquired motor speech impairment with LIPC damage remain valid nearly 150years after his initial report on this issue.
Department of Communication Sciences and Disorders, University of South Carolina, Columbia, SC 29208, USA. j.d.richardson@sc.edu
Jessica D
JD
Richardson
Paul
P
Fillmore
Chris
C
Rorden
Leonard L
LL
Lapointe
Julius
J
Fridriksson
D001039:Aphasia, Broca / Q000209:etiology* / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005625:Frontal Lobe / Q000098:blood supply / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D020521:Stroke / Q000150:complications* / Q000473:pathology*