Priming words with pictures: Neural correlates of semantic associations in a cross‐modal priming task using fMRI

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.