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Keywords:

  • semantic priming;
  • lexical decision;
  • semantic processing;
  • language;
  • fMRI

Abstract

In our everyday life we process information from different modalities simultaneously with great ease. With the current study we had the following goals: to detect the neural correlates of (1) automatic semantic processing of associates and (2) to investigate the influence of different visual modalities on semantic processing. Stimuli were presented with a short SOA (350 ms) as subjects performed a lexical decision task. To minimize the variance and increase homogeneity within our sample, only male subjects were measured. Three experimental conditions were compared while brain activation was measured with a 3 T fMRI scanner: related word-pairs (e.g., frame–picture), unrelated word-pairs (e.g., frame–car) as well as word-nonword pairs (e.g., frame–fubber). They were presented uni- (word -word) and cross-modally (picture–word). Behavioral data revealed a priming effect for cross-modal and unimodal word-pairs. On a neural level, the unimodal condition revealed response suppression in bilateral fronto-parietal regions. Cross-modal priming led to response suppression within the right inferior frontal gyrus. Common areas of deactivation for both modalities were found in bilateral fronto-tempo-parietal regions. These results suggest that the processing of semantic associations presented in different modalities lead to modality-specific activation caused by early access routes. However, common activation for both modalities refers to a common neural network for semantic processing suggesting amodal processing. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc.