Original Investigation

Psychopharmacology

, Volume 202, Issue 4, pp 621-634

Evidence for modulation of facial emotional processing bias during emotional expression decoding by serotonergic and noradrenergic antidepressants: an event-related potential (ERP) study

  • Rebecca KerestesAffiliated withBehavioural Neuroscience Laboratory, School of Psychology, Psychiatry and Psychological Medicine, Monash University Email author 
  • , Izelle LabuschagneAffiliated withBehavioural Neuroscience Laboratory, School of Psychology, Psychiatry and Psychological Medicine, Monash University
  • , Rodney J. CroftAffiliated withBehavioural Neuroscience Laboratory, School of Psychology, Psychiatry and Psychological Medicine, Monash UniversityBiological Psychiatry Research Unit, Brain Sciences Institute, Swinburne University of Technology
  • , Barry V. O’NeillAffiliated withBiological Psychiatry Research Unit, Brain Sciences Institute, Swinburne University of Technology
  • , Zubin BhagwagarAffiliated withClinical Neuroscience Research Unit, Department of Psychiatry, Yale University
  • , K. Luan PhanAffiliated withPsychiatric Affective Neuroimaging Laboratory, Department of Psychiatry, The University of Michigan
  • , Pradeep J. NathanAffiliated withBehavioural Neuroscience Laboratory, School of Psychology, Psychiatry and Psychological Medicine, Monash UniversityBrain Mapping Unit, Department of Psychiatry, University of Cambridge, Addenbrooke’s Hospital Email author 

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Abstract

Rationale

Serotonergic (SSRI) and noradrenergic (NRI) antidepressants modulate biases in emotional processing such that perceptual bias is shifted away from negative and towards positive emotional material. However, the effects of serotonergic and noradrenergic modulation on the temporal course (occurring in milliseconds) of emotional processing, and in particular, the rapid physiological changes associated with the different stages of emotional processing, are unknown.

Objective

The current study assessed the effects of acute serotonergic (i.e. with citalopram) and noradrenergic (i.e. with reboxetine) augmentation on event-related potential (ERP) measures associated with ‘structural encoding’ (N170) and emotion expression decoding (N250 and late positive potential [LPP]) for positive (happy) and negative (sad) facial stimuli relative to neutral facial stimuli.

Materials and methods

This study employed a double-blind, placebo-controlled, cross-over design in which 12 healthy male participants completed a facial expression recognition task tested under three acute conditions: (a) placebo, (b) citalopram (20 mg) and (c) reboxetine (4 mg).

Results

Both citalopram and reboxetine had no effect on the N170 ERP component associated with structural encoding, but potentiated the N250 associated with happy (relative to neutral) emotional facial expression decoding. Both drugs had no valence effects on later ERP measures of emotion expression decoding (LPP).

Conclusions

Citalopram and reboxetine have selective effects on the temporal course of emotional processing with evidence to suggest specific effects on emotion expression decoding of positive (happy) emotional facial stimuli as evidenced by changes in the attention-modulated N250 but not structural encoding. These findings provide physiological evidence that antidepressants may shift perceptual biases in emotional processing away from negative and towards positive stimuli.

Keywords

Serotonin Noradrenaline Antidepressants Emotional processing Face processing Electrophysiology Event-related potential (ERP) N170 N250 Late positive potential (LPP)