Emotion-motion interactions in conversion disorder: an FMRI study.

Selma Aybek,Fernando Zelaya,Timothy R Nicholson,Owen O’Daly,Anthony S David,Richard A Kanaan,Sohee Park

doi:10.1371/journal.pone.0123273

Selma Aybek, Fernando Zelaya + Show 5 more

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https://doi.org/10.1371/journal.pone.0123273

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Abstract

ObjectivesTo evaluate the neural correlates of implicit processing of negative emotions in motor conversion disorder (CD) patients.MethodsAn event related fMRI task was completed by 12 motor CD patients and 14 matched healthy controls using standardised stimuli of faces with fearful and sad emotional expressions in comparison to faces with neutral expressions. Temporal changes in the sensitivity to stimuli were also modelled and tested in the two groups.ResultsWe found increased amygdala activation to negative emotions in CD compared to healthy controls in region of interest analyses, which persisted over time consistent with previous findings using emotional paradigms. Furthermore during whole brain analyses we found significantly increased activation in CD patients in areas involved in the ‘freeze response’ to fear (periaqueductal grey matter), and areas involved in self-awareness and motor control (cingulate gyrus and supplementary motor area).ConclusionsIn contrast to healthy controls, CD patients exhibited increased response amplitude to fearful stimuli over time, suggesting abnormal emotional regulation (failure of habituation / sensitization). Patients with CD also activated midbrain and frontal structures that could reflect an abnormal behavioral-motor response to negative including threatening stimuli. This suggests a mechanism linking emotions to motor dysfunction in CD.

Highlights

Conversion disorder (CD), formerly called hysteria but referred to as functional neurological symptom disorder[1], is the presence of neurological symptoms in the absence of neurological disease
We found increased amygdala activation to negative emotions in CD compared to healthy controls in region of interest analyses, which persisted over time consistent with previous findings using emotional paradigms
During whole brain analyses we found significantly increased activation in CD patients in areas involved in the ‘freeze response’ to fear, and areas involved in self-awareness and motor control

Summary

Introduction

Conversion disorder (CD), formerly called hysteria but referred to as functional neurological symptom disorder[1], is the presence of neurological symptoms in the absence of neurological disease. We have recently shown abnormal activation in cortical regions during an emotional memory task (recall of stressful events of likely aetiological significance) This included abnormal activation in motor planning (supplementary motor area—SMA) and sensory integration regions (right temporo-parietal junction) as well as frontal lobe emotional control areas in patients with sensori-motor CD[4]. A similar limbic-motor interaction has been shown in CD patients presenting with movement disorders during an implicit emotion task (processing of emotional—fearful and happy—faces) with increased amygdala and SMA functional connectivity along with some evidence of a failure to habituate to emotional stimuli[5]. The amygdala ( the centromedial nuclei) has been shown to be involved in affective-motor pathways, both in animals and humans, which might mediate complex motor functions such as the startle response or flight reaction[9]

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