Dopaminergic Modulation of Dynamic Emotion Perception

Abstract

Emotion recognition abilities are fundamental to our everyday social interaction. A large number of clinical populations show impairments in this domain, with emotion recognition atypicalities being particularly prevalent among disorders exhibiting a dopamine system disruption (e.g., Parkinson's disease). Although this suggests a role for dopamine in emotion recognition, studies employing dopamine manipulation in healthy volunteers have exhibited mixed neural findings and no behavioral modulation. Interestingly, while a dependence of dopaminergic drug effects on individual baseline dopamine function has been well established in other cognitive domains, the emotion recognition literature so far has failed to account for these possible interindividual differences. The present within-subjects study therefore tested the effects of the dopamine D2 antagonist haloperidol on emotion recognition from dynamic, whole-body stimuli while accounting for interindividual differences in baseline dopamine. A total of 33 healthy male and female adults rated emotional point-light walkers (PLWs) once after ingestion of 2.5 mg haloperidol and once after placebo. To evaluate potential mechanistic pathways of the dopaminergic modulation of emotion recognition, participants also performed motoric and counting-based indices of temporal processing. Confirming our hypotheses, effects of haloperidol on emotion recognition depended on baseline dopamine function, where individuals with low baseline dopamine showed enhanced, and those with high baseline dopamine decreased emotion recognition. Drug effects on emotion recognition were related to drug effects on movement-based and explicit timing mechanisms, indicating possible mediating effects of temporal processing. Results highlight the need for future studies to account for baseline dopamine and suggest putative mechanisms underlying the dopaminergic modulation of emotion recognition.SIGNIFICANCE STATEMENT A high prevalence of emotion recognition difficulties among clinical conditions where the dopamine system is affected suggests an involvement of dopamine in emotion recognition processes. However, previous psychopharmacological studies seeking to confirm this role in healthy volunteers thus far have failed to establish whether dopamine affects emotion recognition and lack mechanistic insights. The present study uncovered effects of dopamine on emotion recognition in healthy individuals by controlling for interindividual differences in baseline dopamine function and investigated potential mechanistic pathways via which dopamine may modulate emotion recognition. Our findings suggest that dopamine may influence emotion recognition via its effects on temporal processing, providing new directions for future research on typical and atypical emotion recognition.

Keywords: cognition; dopamine; emotion; psychopharmacology; temporal processing; working memory.

Figure 1.

Schematic depiction of main tasks. A, Depiction of one trial of PLW perception task. A fixation cross was presented for 1000 ms and followed by a PLW stimulus (on average 2000 ms). Subsequently, participants rated on three separately presented scales (each ranging from “Not at all” to “Very”) in pseudorandom order how angry, happy, and sad they perceived the PLW stimulus to be. B, Depiction of one trial of visual WM task. After presentation of a fixation cross (duration varied between 500 and 1000 ms), a list of five to nine characters was presented for 1000 ms, followed by a blue fixation cross (3000 ms).

Figure 2.

A, Mean emotion recognition scores for placebo and haloperidol trials by working memory (WM) group. Boxes represent 1 SEM above and below the mean (i.e., horizontal lines within boxes), shaded areas surrounding boxes represent 1 SD above and below mean values. B, C, Probability density function (PDF) of emotion recognition difference scores for low (B) and high (C) WM groups. Emotion recognition difference scores represent the difference between emotion recognition scores in haloperidol and placebo trials, where positive difference scores indicate enhanced emotion recognition performance under haloperidol. The central mark of each of the box plots below PDFs represents the median of each group, edges represent 25th (Q₁) and 75th (Q₃) percentiles. Whiskers denote ranges of Q₃ + 1.5 × (Q₃ – Q₁) above and Q₁ + 1.5 × (Q₃ – Q₁) below box edges.

Figure 3.

A, Drug effects on walking speed by working memory (WM) group. Boxes represent 1 SEM above and below the mean (i.e., horizontal lines within boxes), shaded areas surrounding boxes represent 1 SD above and below mean values. B, Relationship between drug effects on walking speed and drug effects on emotion recognition scores by WM group.