In the present study, the peak of theta power was estimated to the anterior (aIPF) and posterior (pIPF) inferior prefrontal cortices at ∼450 ms (Figure 3). Theta power was significantly greater to SW than to PW. Both of these areas have been implicated in lexical decision tasks. Numerous BOLD–fMRI studies have observed activity in the aIPF during semantic processing (Bookheimer, 2002; Binder et al., 2009), although the exact nature and the semantic specificity of its contribution has been debated (Thompson-Schill et al., 1997; Wagner et al., 2001). Evidence suggests that the pIPF is particularly activated by tasks relying on phonological processing (Poldrack et al., 1999; Binder et al., 2009). This area is commonly more activated by PW than real words during lexical decision making (Clark and Wagner, 2003; Burton et al., 2005), in agreement with its proposed role in phonological processing (Hickok and Poeppel, 2007; Burton, 2009). Furthermore, it is activated across both visual and auditory modalities, suggesting a supramodal role in lexical access (Heim et al., 2007). During a lexical decision task each new stimulus has to be evaluated
