P300 and blink instructions

Objectives: The effects of instructions to refrain from blinking on the P300 event-related brain potential (ERP) from auditory and visual stimuli were assessed. Methods: An oddball paradigm was employed in which young adult subjects (n = 20) silently counted the infrequent target stimuli and were given either no instructions or told ''do not blink" in different conditions, with auditory and visual stimulus tasks employed for all subjects. ERPs were recorded from the midline electrodes, with amplitude and latency of the P300 and other components obtained. Results: P300 amplitude for both modalities and target/standard stimulus conditions was smaller and visual peak latency longer in the "do not blink'' condition. Blink instructions did not directly affect the other components. Conclusions: Instructions to refrain from blinking can decrease P300 amplitude and can increase peak latency. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.