136, P = 0.673) and right IFG (r = 0.008, P = 0.981), nor between the error rate (mean number of errors produced in 13 blocks) and the [HbT] values in the left (r = 0.314, P = 0.320) and right IFG (r = 0.030, P = 0.927). Similar results were obtained in nonword reading, with no significant correlation between the mean number of nonwords read and the [HbT] values in left (r = −0.075, P = 0.337) and right IFG (r = −0.304, P = 0.337), nor between the mean number of errors produced and the [HbT] values measured in the left (r = −0.049, P = 0.879) and

right IFG (r = −0.076, P = 0.814). Discussion The aim of Inhibitors,research,lifescience,medical this study was to investigate the applicability of an fNIRS protocol in studying the patterns of activation for the lexical and phonological pathways of reading. We chose the fNIRS technique because it is resistant to movement artifacts allowing the use of an overt reading task. We used irregular word and nonword stimuli Inhibitors,research,lifescience,medical because the former are most likely to activate the lexical pathway, whereas the latter can be read only through the phonological pathway. The results for [HbT] concentrations,

measured in the total 0- to 20-sec time interval, revealed a significantly higher activation in the bilateral frontal regions in nonword than in irregular word reading. This was not correlated with the reading speed nor accuracy of the participants and is Inhibitors,research,lifescience,medical Inhibitors,research,lifescience,medical consistent with the fMRI study by Joubert et al. (2004) who reported higher activation in the bilateral frontal regions in silent reading of nonwords and low-frequency words compared with high-frequency words. However, our findings contrast with the results of an fMRI study conducted by Mechelli et al. (2005) who reported a left learn more lateralized rather than bilateral difference between pseudowords and irregular words in a silent reading task. As explained in the Introduction, there were no fNIRS studies that compared Inhibitors,research,lifescience,medical the overt reading of irregular words and nonwords. In two fNIRS studies, the researchers tested participants in a lexical decision task involving the silent reading

of words and nonwords (Kahlaoui et al. 2007; Hofmann et al. 2008). While Kahlaoui et al. (2007) found an increase in bilateral activation for nonwords in comparison with words, which ADP ribosylation factor included frontal and temporal regions in young adults and elderly participants, Hofmann et al. (2008), who only recorded hemodynamic responses in the left hemisphere, reported higher activation in the SFG and the IPG for words in comparison with pseudowords. In both of these fNIRS studies, the hemodynamic response reflected the whole processing from the silent reading of the stimuli up to the decision-making process. Because word stimuli can be recognized at the early visual orthographic stage, the participants must not access the sound form of words.