Response-Related Potentials during Semantic Priming: The Effect of a Speeded Button Response Task on ERPs

Abstract

This study examines the influence of a button response task on the event-related potential (ERP) in a semantic priming experiment. Of particular interest is the N400 component. In many semantic priming studies, subjects are asked to respond to a stimulus as fast and accurately as possible by pressing a button. Response time (RT) is recorded in parallel with an electroencephalogram (EEG) for ERP analysis. In this case, the response occurs in the time window used for ERP analysis and response-related components may overlap with stimulus-locked ones such as the N400. This has led to a recommendation against such a design, although the issue has not been explored in depth. Since studies keep being published that disregard this issue, a more detailed examination of influence of response-related potentials on the ERP is needed. Two experiments were performed in which subjects pressed one of two buttons with their dominant hand in response to word-pairs with varying association strength (AS), indicating a personal judgement of association between the two words. In the first experiment, subjects were instructed to respond as fast and accurately as possible. In the second experiment, subjects delayed their button response to enforce a one second interval between the onset of the target word and the button response. Results show that in the first experiment a P3 component and motor-related potentials (MRPs) overlap with the N400 component, which can cause a misinterpretation of the latter. In order to study the N400 component, the button response should be delayed to avoid contamination of the ERP with response-related components.

Sentence Context Prevails Over Word Association in Aphasia Patients with Spared Comprehension: Evidence from N400 Event-Related Potential

“…An explicit response was asked from the subject to keep him/her attentive and to ensure that each word was thoroughly processed. The button press response was delayed to avoid interference of the N400 with response related potentials (Van Vliet et al, 2014). We also used the button press responses to compare the behavioral data with the electrophysiological recordings.…”

ERP Response Unveils Effect of Second Language Manipulation on First Language Processing

“…Contrary to behavioral studies where subjects are requested to press a button immediately after seeing the target word (speeded response task), we implemented a delayed button-press, to avoid contamination of the N400 with response-related ERP components [29], but still to give the subject an explicit task to keep him/her alert. This implies that our reaction time data do not necessarily relate to the semantic priming effect, therefore, we chose not to include it into the analysis.…”

“…This screen remained for 3 s or until the subject responded. Note, that the button-press response was delayed, beyond the time window the N400 ERP is expected, to avoid contamination with response-related ERPs [29]. After pressing the button, the subject received feedback on his/her response: ‘associeert‘ (related) for the left button press and ‘niet associeert‘ (unrelated) for right button press.…”

Overlapping connectivity patterns during semantic processing of abstract and concrete words revealed with multivariate Granger Causality analysis

“…(wrong) otherwise. Since words of the category color were not relevant to the task and required a motor response that could interfere with the electrophysiological response 68 , we removed these trials from our analysis. Therefore, we did not control for the characteristics of these (filler) words.…”