Authors:

HAUK, O., HOLZ, G. & PULVERMULLER, F.

Reference:

Year of publication:

2001

CBU number:

5175

Abstract:

This study investigates topographical electrophysiological differences between categories of action words by means of multi-channel EEG. Applying a lexical decision paradigm, Pulvermuller et al. (NeuroReport 2000, pp. 2789-93) found centres of activation for verbs related to arm-, leg- and face-movements which fit to the representations of the corresponding body parts in the motor strip of the cortex. Significant differences between word categories occurred as early as 240ms after word presentation. We aimed at replicating and extending these results by using a stimulus set which was balanced with respect to several variables, by applying a different paradigm, and by using a different methodology for analysis. Subjects were passively viewing words on a computer screen. Stimuli were balanced with respect to word form frequency, word length, imageability and body-relatedness. Since our hypothesis concerned the differential activation of specific cortical areas, we performed our analyses on current density estimates obtained by minimum norm estimation. We found a significant interaction between the factors word category and topography about 200ms after word presentation. Mouth words activated stronger left-anterior generators compared to foot words, and the foot words activated stronger generators at central sites compared to mouth words. Generators in the right dorsal frontal cortex were stronger for hand/arm-related words compared to both other categories. We conclude that there is a systematic relationship between those body parts involved in the actions to which the words refer and the cortical sources they activate.