Stimulus-Preceding Negativity and heart rate changes in anticipation of affective pictures.

The aim of the present study was to investigate the affective modulation of the Stimulus-Preceding Negativity (SPN) and heart rate changes in anticipation of visual stimuli differing in emotional content. A S1-S2 task was employed with a word (S1) indicating the content of a subsequent emotional picture (S2). Both valence and arousal dimensions were manipulated by presenting positive and negative pictures, high and low in arousal. Irrespective of valence, the amplitude of the SPN resulted to be significantly larger preceding high rather than low arousal pictures, indicating that the SPN does reflect the intensity of the motivational engagement ascribed to affective stimuli. Heart rate responses showed a deceleration preceding S2, which was larger preceding high arousal stimuli in comparison with neutral stimuli. Results suggest a coherent response pattern in both cortical and peripheral measures during affective anticipation.