Localizing interference during naming: Convergent neuroimaging and neuropsychological evidence for the function of Broca's area

Schnur, Tatiana T.; Schwartz, Myrna F.; Kimberg, Daniel Y.; Hirshorn, Elizabeth; Coslett, H. Branch; Thompson-Schill, Sharon L.

doi:10.1073/pnas.0805874106

Localizing interference during naming: Convergent neuroimaging and neuropsychological evidence for the function of Broca's area

^aDepartment of Psychology, Rice University, Houston, TX 77005;
^bMoss Rehabilitation Research Institute, Albert Einstein Healthcare Network, Philadelphia, PA 19141;
Departments of ^cNeurology and
^ePsychology, University of Pennsylvania, Philadelphia, PA 19104; and
^dDepartment of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627

An analysis of this study was presented at the Academy of Aphasia, October 23–25, 2005, Amsterdam, The Netherlands (37).

Edited by Edward E. Smith, Columbia University, New York, NY, and approved November 19, 2008 (received for review June 18, 2008)

Abstract

To produce a word, the intended word must be selected from a competing set of other words. In other domains where competition affects the selection process, the left inferior frontal gyrus (LIFG) responds to competition among incompatible representations. The aim of this study was to test whether the LIFG is necessary for resolution of competition in word production. Using a methodological approach applying the same rigorous analytic methods to neuropsychological data as is done with neuroimaging data, we compared brain activation patterns in normal speakers (using fMRI) with the results of lesion-deficit correlations in aphasic speakers who performed the same word production task designed to elicit competition during lexical selection. The degree of activation of the LIFG in normal speakers and damage to the LIFG in aphasic speakers was associated with performance on the production task. These convergent findings provide strong support for the hypothesis that the region of cortex commonly known as Broca's area (i.e., the posterior LIFG) serves to bias competitive interactions during language production.

Footnotes

¹To whom correspondence should be addressed. E-mail: ttschnur{at}rice.edu
Author contributions: T.T.S., M.F.S., E.H., and S.L.T.-S. designed research; T.T.S. and E.H. performed research; T.T.S., M.F.S., D.Y.K., E.H., H.B.C., and S.L.T.-S. analyzed data; and T.T.S., M.F.S., E.H., and S.L.T.-S. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0805874106/DCSupplemental.