The sensory-motor specificity of taxonomic and thematic conceptual relations: A behavioral and fMRI study

Neural differences in the processing of semantic relationships across cultures

The current study employed functional MRI to investigate the contribution of domain-general (e.g. executive functions) and domain-specific (e.g. semantic knowledge) processes to differences in semantic judgments across cultures. Previous behavioral experiments have identified cross-cultural differences in categorization, with East Asians preferring strategies involving thematic or functional relationships (e.g. cow-grass) and Americans preferring categorical relationships (e.g. cow-chicken). East Asians and American participants underwent functional imaging while alternating between categorical or thematic strategies to sort triads of words, as well as matching words on control trials. Many similarities were observed. However, across both category and relationship trials compared to match (control) trials, East Asians activated a frontal-parietal network implicated in controlled executive processes, whereas Americans engaged regions of the temporal lobes and the cingulate, possibly in response to conflict in the semantic content of information. The results suggest that cultures differ in the strategies employed to resolve conflict between competing semantic judgments.

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.