Functional interactions during the encoding of conceptual action knowledge: an fMRI study

Introduction: Impaired retrieval of conceptual knowledge for actions has been associated with lesions in left premotor, left parietal and left middle temporal areas (Tranel et al., 2003). We aimed at exploring the neural network that is active in healthy subjects during the encoding of conceptual knowledge about actions.

Methods: During functional magnetic resonance imaging three different categories of pictograms (whole-body actions, manipulable objects, non-manipulable objects) were presented. A conjunction analysis of the neural activation elicited by all three pictogram categories revealed a bilateral inferior temporo-occipital and prefrontal network with peaks of activation in the right and left fusiform gyrus (p<0.05, corrected). An analysis of effective connectivity employing psycho-physiological interactions (PPIs) was performed in order to identify contribution-dependent changes in neural responses to the encoding of conceptual knowledge about actions.

Results: Processing of the action pictograms enhanced the neural interaction between the right and left fusiform gyrus and the right and left middle temporal (MT+), the left superior parietal and the left inferior parietal cortex (p<0.05, corrected).

Discussion: These results suggest that knowledge about action concepts is provided by an increased coupling between areas of semantic processing (fusiform gyrus) and both perceptual motion areas (MT+) and areas for movement control (left parietal cortex).