Aversive stimuli exacerbate defensive motor behaviour in motor conversion disorder

Blakemore, Rebekah L; Sinanaj, Indrit; Galli, Silvio; Aybek, Selma; Vuilleumier, Patrik (2016). Aversive stimuli exacerbate defensive motor behaviour in motor conversion disorder. Neuropsychologia, 93(Pt A), pp. 229-241. Elsevier 10.1016/j.neuropsychologia.2016.11.005

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Conversion disorder or functional neurological symptom disorder (FND) can affect the voluntary motor system, without an organic cause. Functional symptoms are thought to be generated unconsciously, arising from underlying psychological stressors. However, attempts to demonstrate a direct relationship between the limbic system and disrupted motor function in FND are lacking. We tested whether negative affect would exacerbate alterations of motor control and corresponding brain activations in individuals with FND. Ten patients and ten healthy controls produced an isometric precision-grip contraction at 10% of maximum force while either viewing visual feedback of their force output, or unpleasant or pleasant emotional images (without feedback). Force magnitude was continuously recorded together with change in brain activity using fMRI. For controls, force output decayed from the target level while viewing pleasant and unpleasant images. Patients however, maintained force at the target level without decay while viewing unpleasant images, indicating a pronounced effect of negative affect on force output in FND. This emotional modulation of force control was associated with different brain activation patterns between groups. Contrasting the unpleasant with the pleasant condition, controls showed increased activity in the inferior frontal cortex and pre-supplementary motor area, whereas patients had greater activity in the cerebellum (vermis), posterior cingulate cortex, and hippocampus. Engagement of a cerebellar-limbic network in patients is consistent with heightened processing of emotional salience, and supports the role of the cerebellum in freezing responses in the presence of aversive events. These data highlight a possible neural circuit through which psychological stressors elicit defensive behaviour and modulate motor function in FND.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology

UniBE Contributor:

Aybek, Selma

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0028-3932

Publisher:

Elsevier

Language:

English

Submitter:

Stefanie Hetzenecker

Date Deposited:

07 Feb 2017 16:00

Last Modified:

07 Feb 2017 16:00

Publisher DOI:

10.1016/j.neuropsychologia.2016.11.005

PubMed ID:

27842291

Uncontrolled Keywords:

Cerebellum vermis; Emotion; Force control; Freezing; Functional symptoms

BORIS DOI:

10.7892/boris.90715

URI:

https://boris.unibe.ch/id/eprint/90715

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