Reduced sympathetic activation to pleasant pictures in depression and anxiety
Résumé
Emotional information is known to evoke bodily responses involving specific autonomic patterns. However, these patterns of response could be modulated both by the location of the emotional information in the visual space and by psychological traits of individuals. Hence, the aim of this study was (1) to compare autonomic markers variations in response to emotional pictures presented in central and peripheral vision (CV, PV) and (2) to investigate the relation between these variations and depressive and anxious traits. Twenty-four healthy participants were presented with 3 sets of 16 pictures (unpleasant, neutral and pleasant) from the International Affective Picture System, at three eccentricities (). The sets had been balanced as for main physical properties of the pictures, among which brightness, contrast and spatial frequencies. Participants had to fixate a cross in the center of the screen and to report the location of the pictures (left, center or right). Participants fulfilled questionnaires (depression, BDI; anxiety, STAI; social anxiety, BFNE) and the pupil diameter and the cardiac frequency indices, both under the sympathetic-parasympathetic control, were recorded. Participants showed greater pupil constriction to unpleasant than pleasant pictures, but only in PV. A greater latency of cardiac acceleration for unpleasant than for pleasant stimuli was also observed, but only for stimuli presented on the left side. Interestingly, the more the participants were anxious, the more their pupil diminished in response to pleasant stimuli in CV. In addition, the more the participants were depressed, anxious and socially anxious,
the shorter was their cardiac acceleration latency in response to left pleasant stimulation.
This study (1) confirms the fact that the sympathetic system is more activated by pleasant than unpleasant visual information and (2) illustrates for the first time the reduction of such activation by depressive and anxious traits.