Author contribution: Fokin VF — study concept, manuscript writing; Ponomareva NV — statistical analysis, manuscript writing; Medvedev RB — duplex ultrasonography, hemodynamic data analysis; Konovalov RN — fMRI data acquisition and analysis; Krotenkova MV — fMRI data analysis, study design; Lagoda OV — clinical data analysis; Tanashyan MM — clinical data analysis, study design.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Research Center of Neurology (protocol № 11/14 dated November 19, 2014); the informed consent was submitted by all patients.