title: Frontal midline theta rhythm and gamma power changes during focused attention on mental calculation: an MEG beamformer analysis.
abstract: Frontal midline theta rhythm (Fmθ) appears widely distributed over medial prefrontal areas in EEG recordings, indicating focused attention. Although mental calculation is often used as an attention-demanding task, little has been reported on calculation-related activation in Fmθ experiments. In this study we used spatially filtered MEG and permutation analysis to precisely localize cortical generators of the magnetic counterpart of Fmθ, as well as other sources of oscillatory activity associated with mental calculation processing (i.e., arithmetic subtraction). Our results confirmed and extended earlier EEG/MEG studies indicating that Fmθ during mental calculation is generated in the dorsal anterior cingulate and adjacent medial prefrontal cortex. Mental subtraction was also associated with gamma event-related synchronization, as an index of activation, in right parietal regions subserving basic numerical processing and number-based spatial attention. Gamma event-related desynchronization appeared in the right lateral prefrontal cortex, likely representing a mechanism to interrupt neural activity that can interfere with the ongoing cognitive task.
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Ryouhei
authors: R
authors: Ishii
authors: Department of Cognitive and Computational Neuroscience, Centre for Biomedical Technology, Complutense University of Madrid, UPM Madrid, Spain.
authors: Leonides
authors: L
authors: Canuet
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Tsutomu
authors: T
authors: Ishihara
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Yasunori
authors: Y
authors: Aoki
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan ; Osaka Psychiatric Medical Center Hirakata, Japan.
authors: Shunichiro
authors: S
authors: Ikeda
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Masahiro
authors: M
authors: Hata
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Themistoklis
authors: T
authors: Katsimichas
authors: Faculty of Education and Human Sciences, Course of School Education, Yokohama National University Yokohama, Japan.
authors: Atsuko
authors: A
authors: Gunji
authors: Department of Child and Adolescent Mental Health, National Center for Neurology and Psychiatry, National Institute of Mental Health Kodaira, Japan.
authors: Hidetoshi
authors: H
authors: Takahashi
authors: Department of Child and Adolescent Mental Health, National Center for Neurology and Psychiatry, National Institute of Mental Health Kodaira, Japan.
authors: Takayuki
authors: T
authors: Nakahachi
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Masao
authors: M
authors: Iwase
authors: Department of Psychiatry, Osaka University Graduate School of Medicine Suita, Japan.
authors: Masatoshi
authors: M
authors: Takeda
keywords: arithmetic calculation; beamformer; focused attention; frontal midline theta; gamma band; magnetoencephalography (MEG); spatial filtering; synthetic aperture magnetometry (SAM)