title: EEG frequency dynamics during movements imagery.
abstract: The study is an attempt to reveal the EEG frequency dynamic changes over sites covering areas reflecting the cognitive processes during movement imagery. Subjects were instructed to imagine a self-paced movement after listening to randomized sentences differing in lack of object or instrument of action. EEG was recorded over frontal, sensorimotor and temporo-parietal areas in both hemispheres. Frequency dynamics was estimated using power spectra (PS), band-pass filtering and bispectra. Two types of frequency dynamics were established: (A) a linear one, up to 24 Hz, with most pronounced oscillations in 12-14 Hz and in 16-22 Hz, synchronized first in frontal and precentral areas; (B) a nonlinear one between 24 and 63 Hz, with fractal structure and self-similarity, characterized by fractal dimension of 1.7-1.9. The narrow band of 23-26 Hz in the boundary between linear and nonlinear regimes expressed obvious synchronization and time re-distribution of oscillations among sites and sentence-types.
authors.affiliation: Motor Control Laboratory, Institute of Physiology, BAS, Sofia, Bulgaria. dapo@bio.bas.bg
authors.forename: D
authors.initials: D
authors.lastname: Popivanov
authors.forename: L
authors.initials: L
authors.lastname: Likova
authors.forename: Z
authors.initials: Z
authors.lastname: Sauleva
mesh_terms: D004538:Eidetic Imagery; D004566:Electrodes; D004569:Electroencephalography; D006801:Humans; D017711:Nonlinear Dynamics; D011597:Psychomotor Performance / Q000502:physiology*