To elucidate the neural basis of stuttering, brain activation for reading words was compared between adults who do and do not stutter (AWS/ANS) with functional MRI. Japanese native speakers read aloud familiar (F), unfamiliar (U) and pseudo- (P) words of 4 or 5 syllables. P contained much fewer native syllable sequences than F or U. F primarily activated the left angular/supramarginal gyri (lAG/SMG), U Broca's area, and P the left ventral premotor/motor areas (lvPMA/MA), respectively, in ANS. AWS showed lower activation in lAG/SMG and Broca's area, but higher activation in lvPMA/MA, implying that AWS cannot read native syllable sequences as efficiently as ANS.
