title: Negative emotions facilitate isometric force through activation of prefrontal cortex and periaqueductal gray.
abstract: Emotions are considered to modulate action readiness. Previous studies have demonstrated increased force production following exposure to emotionally arousing visual stimuli; however the neural mechanisms underlying how precise force output is controlled within varying emotional contexts remain poorly understood. To identify the neural correlates of emotion-modulated motor behaviour, twenty-two participants produced a submaximal isometric precision-grip contraction while viewing pleasant, unpleasant, neutral or blank images (without visual feedback of force output). Force magnitude was continuously recorded together with change in brain activity using functional magnetic resonance imaging. Viewing unpleasant images resulted in reduced force decay during force maintenance as compared with pleasant, neutral and blank images. Subjective valence and arousal ratings significantly predicted force production during maintenance. Neuroimaging revealed that negative valence and its interaction with force output correlated with increased activity in right inferior frontal gyrus (rIFG), while arousal was associated with amygdala and periaqueductal gray (PAG) activation. Force maintenance alone was correlated with cerebellar activity. These data demonstrate a valence-driven modulation of force output, mediated by a cortico-subcortical network involving rIFG and PAG. These findings are consistent with engagement of motor pathways associated with aversive motivation, eliciting defensive behaviour and action preparedness in response to negative emotional signals.
authors.affiliation: Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, University Medical Centre, University of Geneva, Geneva, Switzerland; Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland. Electronic address: rebekah.blakemore@otago.ac.nz.
authors.forename: Rebekah L
authors.initials: RL
authors.lastname: Blakemore
authors.affiliation: Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, Geneva, Switzerland. Electronic address: sebastian.rieger@unige.ch.
authors.forename: Sebastian W
authors.initials: SW
authors.lastname: Rieger
authors.affiliation: Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, University Medical Centre, University of Geneva, Geneva, Switzerland; Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, Geneva, Switzerland; Department of Neurology, University Hospitals of Geneva, Geneva, Switzerland. Electronic address: patrik.vuilleumier@unige.ch.
authors.forename: Patrik
authors.initials: P
authors.lastname: Vuilleumier
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology*; D001143:Arousal; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D018737:Hand Strength; D006801:Humans; D007537:Isometric Contraction; D008279:Magnetic Resonance Imaging; D008297:Male; D010487:Periaqueductal Gray / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance; D055815:Young Adult
keywords: Defensive behaviour; Emotion; Force control; Freezing; Inferior frontal gyrus