An Integrative Neurocircuit Perspective on Psychogenic Non-Epileptic Seizuresand Functional Movement Disorders: Neural Functional Unawareness

摘要

Functional Neurological Disorder (conversion disorder) is a neurobehavioral condition frequently encountered by neurologists. Psychogenic Non-Epileptic Seizure (PNES) and Functional Movement Disorder (FMD) patients present to epileptologists and movement disorder specialists respectively, yet neurologists lack a neurobiological perspective through which to understand these enigmatic groups. Observational research studies suggest that PNES and FMD may represent variants of similar (or the same) conditions given that both groups exhibit a female predominance, have increased prevalence of mood-anxiety disorders, frequently endorse prior abuse, and share phenotypic characteristics. In this perspective article, neuroimaging studies in PNES and FMD are reviewed, and discussed using studies of emotional dysregulation, dissociation and psychological trauma in the context of motor control. Convergent neuroimaging findings implicate alterations in brain circuits mediating emotional expression, regulation and awareness (anterior cingulate and ventromedial prefrontal cortices, insula, amygdala, vermis), cognitive control and motor inhibition (dorsal anterior cingulate, dorsolateral prefrontal, inferior frontal cortices), self-referential processing and perceptual awareness (posterior parietal cortex, temporoparietal junction), and motor planning and coordination (supplementary motor area, cerebellum). Striatal-thalamic components of prefrontal-parietal networks mayalso play a role in pathophysiology. Aberrant medial prefrontal and amygdalar neuroplasticchanges mediated by chronic stress may facilitate the development of functionalneurological symptoms in a subset of patients. Improved biological understanding of PNESand FMD will likely reduce stigma and aid the identification of neuroimaging biomarkersguiding treatment development, selection and prognosis. Additional research shouldinvestigate neurocircuit abnormalities within and across functional neurological disordersubtypes, as well as compare PNES and FMD to mood-anxiety-dissociative disorders.