The Neural Circuitry Involved in the Reading of German Words and Pseudowords: A PET Study

Abstract

Silent reading and reading aloud of German words and pseudowords were used in a PET study using ( 15 O)butanol to examine the neural correlates of reading and of the phonological conversion of legal letter strings, with or without meaning. The results of 11 healthy, right-handed volunteers in the age range of 25 to 30 years showed activation of the lingual gyri during silent reading in comparison with viewing a xation cross. Comparisons between the reading of words and pseudowords suggest the involvement of the middle temporal gyri in retrieving both the phonological and semantic code for words. The reading of pseudowords activates the left inferior frontal gyrus, including the ventral part of Broca's area, to a larger extent than the reading of words. This suggests that this area might be involved in the sublexical conversion of orthographic input strings into phonological output codes. (Pre)motor areas were found to be activated during both silent reading and reading aloud. On the basis of the obtained activation patterns, it is hypothesized that the articulation of high-frequency syllables requires the retrieval of their concomitant articulatory gestures from the SMA and that the articulation of lowfrequency syllables recruits the left medial premotor cortex.

Functional Dynamics of Dorsal and Ventral Reading Networks in Bilinguals

“…The fact that this effect in the pars opercularis, STG and pars orbitalis was only present in L1 reading may be due to further attempts to phonologically decode and retrieve representations in the native language. Although there is prior evidence showing higher activation for pseudowords than words in these regions (Hagoort et al 1999;Burton et al 2005), this is the first study showing that this effect is present in L1 but not in L2 reading. These results partially confirmed, and qualified, hypothesis IV.…”

The role of inferior frontal cortex in phonological processing

“…However, differences between reading of words and pseudowords and between sets of words with carefully controlled properties such as frequency and consistency of sound to spelling mapping are now being explored in word reading tasks (Fiez et al, 1999;Hagoort et al, 1999;Paulesu et al, 2000). Inferior frontal activation has emerged in conditions such as reading nonwords that require an increased amount of grapheme to phoneme conversion compared to reading words.…”

Some neurophysiological constraints on models of word naming

“…One relatively reliable finding is stronger activation to nonwords than words in the left frontal operculum and adjacent anterior insula (Fiez et al, 1999;Hagoort et al, 1999;Herbster et al, 1997;Mechelli et al, 2003;Paulesu et al, 2000;Xu et al, 2001). Because the dual-route model proposes greater reliance on the nonlexical GPC system in the case of nonwords, these findings have often been interpreted as evidence for such a system in the left inferior frontal lobe.…”