Emotional stimuli and motor conversion disorder

Abstract

Conversion disorder is characterized by neurological signs and symptoms related to an underlying psychological issue. Amygdala activity to affective stimuli is well characterized in healthy volunteers with greater amygdala activity to both negative and positive stimuli relative to neutral stimuli, and greater activity to negative relative to positive stimuli. We investigated the relationship between conversion disorder and affect by assessing amygdala activity to affective stimuli. We conducted a functional magnetic resonance imaging study using a block design incidental affective task with fearful, happy and neutral face stimuli and compared valence contrasts between 16 patients with conversion disorder and 16 age- and gender-matched healthy volunteers. The patients with conversion disorder had positive movements such as tremor, dystonia or gait abnormalities. We also assessed functional connectivity between the amygdala and regions associated with motor preparation. A group by affect valence interaction was observed. Post hoc analyses revealed that whereas healthy volunteers had greater right amygdala activity to fearful versus neutral compared with happy versus neutral as expected, there were no valence differences in patients with conversion disorder. There were no group differences observed. The time course analysis also revealed greater right amygdala activity in patients with conversion disorder for happy stimuli (t = 2.96, P = 0.006) (with a trend for fearful stimuli, t = 1.81, P = 0.08) compared with healthy volunteers, with a pattern suggestive of impaired amygdala habituation even when controlling for depressive and anxiety symptoms. Using psychophysiological interaction analysis, patients with conversion disorder had greater functional connectivity between the right amygdala and the right supplementary motor area during both fearful versus neutral, and happy versus neutral 'stimuli' compared with healthy volunteers. These results were confirmed with Granger Causality Modelling analysis indicating a directional influence from the right amygdala to the right supplementary motor area to happy stimuli (P < 0.05) with a similar trend observed to fearful stimuli (P = 0.07). Our data provide a potential neural mechanism that may explain why psychological or physiological stressors can trigger or exacerbate conversion disorder symptoms in some patients. Greater functional connectivity of limbic regions influencing motor preparatory regions during states of arousal may underlie the pathophysiology of motor conversion symptoms.

Brain circuits implicated in psychogenic paralysis in conversion disorders and hypnosis

“…Similar evidence has been gathered in recent studies [101][102][103] concerning patients with psychogenic movement disorders such as tremor or dystonia (i.e., positive rather negative motor symptoms), although pointing to the role of different circuits connecting the amygdala to SMA (see also review by Voon et al in this issue). Future research should use more advanced connectivity measures such as dynamic causal modelling (DCM) and compare different conversion patient groups during different symptomatic conditions (pre-vs. post-recovery) to gain better insights into such interactions between motor control and emotion/motivation systems.…”

“…On the other hand, however, unlike the classic view, conversion and hypnosis appear to act on behavior and perception via partly distinct brain circuits. In conversion, modulations of motor and sensory awareness might primarily be driven by an increased recruitment of regions in VMPFC, implicated in the access to self-relevant affective representations and memories [17,104,105,107], as well as other subcortical limbic regions such as the amygdala [45,79,101,102]. These areas might influence movement, sensation, and self-awareness more broadly by promoting or suppressing certain patterns of behaviors through modulatory inputs to motor or sensory pathways (as observed for more primitive adaptive reactions to threat, see [47,104,110]), and/or by imbuing behavior with particular affective and self-relevant associations though an integration of sensorimotor activity with internal representations retrieved from memory or imagery.…”

Why should we change the term psychogenic nonepileptic seizures?

“…Of note, these cerebral abnormalities and volume losses that were depicted in patients with PNES had been previously demonstrated in patients with psychogenic movement disorders. 13 On this basis, for several reasons, we would be very reluctant to go along with the suggestion of Brigo et al First of all, the true apparent lack of interest by mental health professionals as mentioned in their proposal does not parallel with the lack of training among epileptologists, as clearly demonstrated by the huge body of scientific literature published by the neurology/epilepsy community and the awareness of this issue as recently proposed by the ILAE Nonepileptic Seizure Task Force. Second, we believe that the use of the term "seizure" is correct consisting, by definition, of a sudden onset of symptoms, and it fits among the different categories of seizures, also considering the high occurrence of combination of epileptic and psychogenic nonepileptic seizures in the same patient.…”

Correlação dos parâmetros endócrinos e comportamentais em cadelas abandonadas em programa de ressocialização

“…et al, 2012;LEUNER;SHORS, 2013) levando à previsibilidade futura, o que se reflete em ansiedade (DRESCHEL, NANCY., 2010;O'DONOVAN et al, 2010;LEUNER;SHORS, 2013;PASSALACQUA et al, 2013). Em humanos, este tremor independente do medo foi estudado em situações de alegria extrema, e algumas pessoas com transtorno de conversão apresentam tremores na demonstração de alegria por haver conectividade entre a amígdala e regiões associadas com a preparação motora (VOON et al, 2010 KING et al, 2000;HENNESSY et al, 2001;HAVERBEKE et al, 2008;KERSWELL et al, 2009), abanar a cauda. (SINISCALCHI et al, 2013), intensidade da receptividade e a socialização (BEERDA et al, 2000).…”