Abstract
Emotional modulation of defensive reflexes by viewing affective pictures. We present the results of a study aimed to examine the modulation of the cardiac defense response and the startle reflex (eyeblink), elicited by acoustic stimuli, by simultaneous visualization of affective pictures selected from the Spanish adapta tion of the International Affective Picture System. 60 volunteer student women participated in the study. The psychophysiolog ical test consisted of 9 trials in whic h 3 pleasant, 3 unpleasant and 3 neutral pictures were presented, in counterbalanced order, during 6 seconds, with an intertrial interval between 95 and 120 seconds. Each visualization trial was accompanied by the presentation, through headphones, of a w hite noise of 105 dB intensity, 500 ms duration and instantaneous risetime. The noise was initiated 3.5 s after initiation of the picture. Dependent variables were secondby-second heart rate and integrated electromyography of the orbicular is oculi muscle. Results show a potentiation of both the cardiac defense response and the startle reflex by visualization of unpleasant pictures. Visualization of pleasant pictures showed inhibition, as compared to neutral pictures, only of the startle reflex. These results give support to the motivational priming theory of defensive reflexes proposed by Lang and confirm the dynamic and sequential character of the cardiac defense response.
