The potential of restingstate functional magnetic resonance imaging for studying the pathophysiology of primary focal dystonia
Restingstate functional magnetic resonance imaging (RfMRI) assesses the state of lowfrequency fluctuations of the BOLDsignal showing spontaneous neuronal activity in different areas of the brain. Hence, RfMRI allows one to visualize the synchronicity of generation of certain neurophysiological phenomena in different regions of the central nervous system, including the ones being remote from one another, by linking them into a functional network and assessing brain connectivity in normal state and in pathology. This technique has proved itself in the study of neurodegenerative diseases. In this review, we present the results of using RfMRI for the most common forms of primary focal dystonia (blepharospasm and cervical dystonia) compared to the data of taskbased fMRI and some other neuroimaging technologies such as positron emission tomography and voxelbased morphometry. It has been demonstrated in many studies that RfMRI allows to assess disturbances in cerebral architecture and complex rearrangements in the neural network in patients with focal dystonia, including those after administration of botulinum toxin. This makes it possible to study more thoroughly the pathophysiological foundations of focal dystonia and the variety of mechanisms of botulinum toxin therapy in patients with these pathologies, including the central (indirect) mechanisms of action of botulinum toxin.