The brain bases of reading late learned words: Evidence from functional MRI

Abstract

Age of acquisition (AoA) effects for reading have been documented in the literature. Recent studies have suggested that more effortful phonological retrieval is involved in picture naming for late learned words. Here we use functional magnetic resonance imaging to determine the neuroanatomical correlates of AoA effects in reading, and to explore whether AoA effects in the brain modulate activity in areas devoted to phonological processing. Participants were asked to covertly name blocks of early and late learned words while being scanned with functional MRI. Results revealed a relative increase in neural activity for late learned words in a set of brain areas involved in auditory-phonological processing (the planum temporale of the posterior-superior left temporal lobe) and articulatory motor planning (BA 44, putamen, and globus pallidus). These findings support the view that late learned words involve more effortful phonological retrieval, but in addition point to a second locus of the AoA effect in the articulatory component of the reading system.

Support for this work was provided by the grants entitled “fMRI studies on language and task switching in Spanish-English Bilinguals” (NSF BCS0092043) and “Neural correlates of grammatical gender processing” (NSF INT0202686).

Support for this work was provided by the grants entitled “fMRI studies on language and task switching in Spanish-English Bilinguals” (NSF BCS0092043) and “Neural correlates of grammatical gender processing” (NSF INT0202686).

Acknowledgments

We would also like to thank Fred Saab for assistance in data analysis and Vivian Valentin, Benjamin Storm, and Ann Firestine for assistance in data collection.

Notes

Support for this work was provided by the grants entitled “fMRI studies on language and task switching in Spanish-English Bilinguals” (NSF BCS0092043) and “Neural correlates of grammatical gender processing” (NSF INT0202686).

²Note that it is highly unlikely that the reported activation differences are due to the remaining differences in imageability between early and late learned words, as none of the reported areas has been associated with imageability before (e.g., Fiebach et al., 2003; Wise et al., 2000).