Pupil diameter was monitored during picture viewing to assess effects of hedonic valence and emotional arousal on pupillary responses. Autonomic activity (heart rate and skin conductance) was concurrently measured to determine whether pupillary changes are mediated by parasympathetic or sympathetic activation. Following an initial light reflex, pupillary changes were larger when viewing emotionally arousing pictures, regardless of whether these were pleasant or unpleasant. Pupillary changes during picture viewing covaried with skin conductance change, supporting the interpretation that sympathetic nervous systemactivity modulates these changes in the context of affective picture viewing. Taken together, the data provide strong support for the hypothesis that the pupil's response during affective picture viewing reflects emotional arousal associated with increased sympathetic activity. DescriptorsPupil; Arousal; Emotion; Pleasure; Sympathetic; Skin conductance Hess (e.g., Hess & Polt, 1960) famously reported bi-directional effects of emotion on pupil change, reporting that the pupil constricted (shut down) when people viewed unpleasant pictures and dilated when they viewed pleasant pictures. These results proved difficult to replicate, however, and this early research suffered from numerous methodological difficulties, including the use of very few pictures (e.g., five), very small number of subjects (e.g., five), the method of assessing pupil change, and no statistical analysis. Libby, Lacey, and Lacey (1973) later conducted amore extensive investigation of pupillary changes during affective picture viewing, presenting 30 pictures to 34 participants while both pupil diameter and heart rate were measured. In their study, the pupil was photographed two times a second during a 15-s exposure for each picture. Then, "six clerks" scored the resulting 81,600 measurements on the basis of a wall chart onto which the negative was projected. The reported results were somewhat confusing: Although "attention-getting" pictures, a factor onto which emotionality loaded, was associated with greater pupil dilation, a second "pleasure" factor suggested that neutral pictures prompted larger pupil dilation than emotional pictures.

Thus, when cerebral metabolism of ethanol into acetaldehyde is blocked by catalase inhibitors, or acetaldehyde is inactivated, there is a suppressive effect on the anxiolytic actions of ethanol. These data provide further support for the idea that centrally formed or administered acetaldehyde can contribute to some of the psychopharmacological actions of ethanol, including its anxiolytic properties.

No abstract

Increased attention among the research community in exploring underlying mechanisms of emotion regulation has prompted a growth of experimental works in this field. Empirical studies have mainly focused on self‐reports, brain imaging, and electrophysiological measures, with only a few works exploring peripheral physiology. Additionally, most of such studies have not considered the specific stimuli content, even though prior literature has shown relevant differences in psychophysiological and subjective responses depending on picture categories. The current study assessed several peripheral correlates (startle amplitude, electrodermal changes, heart rate) of emotion regulation processes in a sample of 122 healthy participants. The task consisted of voluntary reappraisal of negative emotions prompted by unpleasant pictures (threat to others and victims), compared to a nonregulation control condition (looking at exemplars of the same categories and household objects). Results showed an effect of emotion regulation instructions in all psychophysiological and subjective measures. In peripheral physiology, greater responses were observed specifically when increasing negative emotions, concurring with previous research. Regarding specific content, our findings evidence a similar emotion regulation pattern, independently of the unpleasant category, suggesting a plausible effect of cognitive variables (such as cognitive effort) during voluntary reappraisal for both categories.

The scientific study of emotions has been of great interest for decades and it has raised numerous theoretical and experimental questions, such as the suitability of affective stimuli used for inducing emotions (Moltó et al., 1999(Moltó et al., , 2013. Most of the previous studies have focused on the use of affective pictures, facial expressions, words, or sounds to induce emotions in laboratory settings, obtaining clear and wellestablished results. However, the number of studies focused