Electrocortical signature of emotion verb processing

Abstract

Motion verbs elicit patterns of anterior electrocortical activity that are assumed to reflect the involvement of the motor cortex in the representation of their meaning. However, little is known about other semantic categories such as verbs that refer to emotional actions. In order to explore how these verbs are represented, we compared the electrocortical activity generated by the identification of forty emotion verbs (e.g. ‘‘to yearn’’) and forty motion verbs (e.g., ‘‘to twirl’’) matched on lexical frequency, orthographic neighborhood size and length, but different in emotional valence. Event related potentials from ten healthy students were recorded while they performed a lexical decision task in which the target verbs were presented along with eighty pseudoverbs (e.g. ‘‘to scrout’’). EEG was recorded using a 128-channelNet (EGI, Eugene, Oregon). Impedance was kept below 50 kOhm. Sampling rate was 250 Hz. EEG was band-pass filtered between .3 and 40 Hz and segmented from 100 ms before to 600 ms after stimulus onset. Segments were baseline corrected and re-referenced to the mastoids. Emotion verbs appeared to be associated with larger positive amplitudes than motion verbs at early (150 – 200 ms) and late (450 – 500 ms) time-windows. Furthermore, the effect of verb category significantly interacted with electrode position at intermediate stages (250 – 350 ms), with emotion verbs eliciting a much larger positivity than motion verbs at anterior compared to posterior electrodes. We conclude that semantic processing of emotion-related verbs is reflected in anterior brain activation.