title: Influence of coherence between multiple cortical columns on alpha rhythm: a computational modeling study.
abstract: In electroencephalographic (EEG) and magnetoencephalographic (MEG) signals, stimulus-induced amplitude increase and decrease in the alpha rhythm, known as event-related synchronization and desynchronization (ERS/ERD), emerge after a task onset. ERS/ERD is assumed to reflect neural processes relevant to cognitive tasks. Previous studies suggest that several sources of alpha rhythm, each of which can serve as an alpha rhythm generator, exist in the cortex. Since EEG/MEG signals represent spatially summed neural activities, ERS/ERD of the alpha rhythm may reflect the consequence of the interactions between multiple alpha rhythm generators. Two candidates modulate the magnitude of ERS/ERD: (1) coherence between the activities of the alpha rhythm generators and (2) mean amplitude of the activities of the alpha rhythm generators. In this study, we use a computational model of multiple alpha rhythm generators to determine the factor that dominantly causes ERS/ERD. Each alpha rhythm generator is modeled based on local column circuits in the primary visual cortex and made to interact with the neighboring generators through excitatory connections. We observe that the model consistently reproduces spontaneous alpha rhythms, event-related potentials, phase-locked alpha rhythms, and ERS/ERD in a specific range of connectivity coefficients. Independent analyses of the coherence and amplitude of multiple alpha rhythm generators reveal that the ERS/ERD in the simulated data is dominantly caused by stimulus-induced changes in the coherence between multiple alpha rhythm generators. Nonlinear phenomena such as phase-resetting and entrainment of the alpha rhythm are related to the neural mechanism underlying ERS/ERD.
authors.affiliation: Biological ICT Group, Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology, Kobe, Japan. y_naruse@po.nict.go.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Naruse
authors.forename: Ayumu
authors.initials: A
authors.lastname: Matani
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Miyawaki
authors.forename: Masato
authors.initials: M
authors.lastname: Okada
mesh_terms: D000328:Adult; D000465:Algorithms; D000513:Alpha Rhythm; D003198:Computer Simulation; D003344:Cortical Synchronization; D004569:Electroencephalography; D005071:Evoked Potentials; D006801:Humans; D015225:Magnetoencephalography; D008959:Models, Neurological; D017711:Nonlinear Dynamics; D010507:Periodicity; D017966:Pyramidal Cells / Q000502:physiology; D013997:Time Factors; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D055815:Young Adult