An alternative perspective holds that the meanings Olaparib in vivo of abstract words are heavily dependent on the linguistic context in which they are being used (in line with the idea that knowledge of abstract words is tied strongly to language use). Initial evidence for this proposal was presented by Schwanenflugel and colleagues (Schwanenflugel et al., 1988 and Schwanenflugel

and Shoben, 1983), who noted that when participants were presented with an abstract word, they found it hard to generate a plausible context in which it could be used. More recently, Hoffman, Lambon Ralph, and Rogers (2013) conducted a quantitative analysis of the contextual usage of a large set of words, using a measure of contextual variability called semantic diversity. They found that abstract words tended to appear in a broader variety of contexts than did concrete words. We have argued that the greater semantic diversity of abstract words means that they place greater demands on executive semantic

control processes that provide top-down regulation of knowledge ( Hoffman et al., 2010 and Hoffman et al., 2011). Semantic control processes interact with semantic representations to ensure that the information accessed at any given moment is appropriate to the current task and context ( Badre and Wagner, 2002, TSA HDAC supplier Jefferies, 2013, Jefferies and Lambon Ralph, 2006 and Thompson-Schill et al., 1997). Because abstract words can occur in many different contexts, with different semantic information potentially required in each, top-down control of knowledge retrieval is thought to be particularly critical for successful comprehension of these words. In summary, there are two perspectives on the nature of differences between concrete and abstract words, one proposing differences in the types and quantity of semantic knowledge involved in each and one proposing

differential involvement of semantic control processes in each as a result of contextual variability. These two perspectives have often been treated as competing IMP dehydrogenase hypotheses (e.g., Binder, Westbury, McKiernan, Possing, & Medler, 2005). In this study, we evaluated a different possibility: namely that both perspectives are correct but that they apply to different neural regions within the semantic network. Semantic control is most strongly associated with the left inferior frontal gyrus (IFG) (Badre and Wagner, 2007 and Thompson-Schill et al., 1997). This region shows increases in activation when participants select among semantic competitors (Badre et al., 2005 and Thompson-Schill et al., 1997) and when semantic ambiguity must be resolved (Bedny et al., 2008, Rodd et al., 2005 and Zempleni et al., 2007).