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.
Kircher
Tilo
T
Department of Psychiatry und Psychotherapy, Philipps-University Marburg, Marburg, Germany. kircher@med.uni-marburg.de
Sass
Katharina
K
Sachs
Olga
O
Krach
Sören
S
D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D001931:Brain Mapping; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D012660:Semantics