When lexical selection gets tough, the LIFG gets going: A lesion analysis study of interference during word production

Abstract

Nonaphasic speakers take longer to name a repeated series of pictures from the same semantic category vs. mixed categories, due to semantically mediated competition for lexical selection (Damian, Vigliocco, & Levelt, 2001). Thompson-Schill et al. (1998) argued that damage to the left inferior frontal gyrus (LIFG) compromises selection when competition is high. Consistent with this, anterior (Broca) aphasics showed a larger blocking effect (more errors in semantically homogeneous vs. mixed blocks) compared to posterior aphasics, and this effect linearly increased across repetitions (Schnur, Brecher, Rossi, & Schwartz, 2004). In this study, we analyzed high-resolution structural MRI and CT scans, collected from a subgroup of aphasics reported by Schnur et al., to directly examine the relationship between the LIFG and the semantic blocking effect.