title: Global synchronization in the theta band during mental imagery of navigation in humans.
abstract: Visual mental imagery is critical for successfully navigating the environment, which in turn activates many cortical regions simultaneously. Theta oscillation is implicated in navigation and brain synchronization. In this study, EEG coherence was analyzed during 3 tasks: subjects (1) mentally simulated jogging along the walls of a gym and pressed a button when they imagined arriving at a corner (jogging imagery task), (2) thought of and memorized one digit after pressing a button 5 times and recalled the digits sequentially after pressing the button again (digit imagery task), and (3) pressed a button (button pressing task). The results indicated that theta-wave (4-8 Hz) power was significantly higher in the frontal and parietal regions during the digit and jogging imagery tasks. Coherence at the theta band showed almost no differences between the button pressing and digit imagery tasks. Coherence between the distant regions, especially between the frontal and parieto-occipital regions and between interhemispheric regions, was significantly higher during the jogging imagery task. Increase in theta power during the jogging imagery task reflects working memory load to manipulate internal information. Theta oscillation appears to play an important role in large-scale synchronization to form the functional neuronal networks required for mental navigation.
authors.affiliation: System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama-ken, Toyama 930-0194, Japan.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Katsumi
authors.initials: K
authors.lastname: Umeno
authors.forename: Etsuro
authors.initials: E
authors.lastname: Hori
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Takakura
authors.forename: Susumu
authors.initials: S
authors.lastname: Urakawa
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Ono
authors.forename: Hisao
authors.initials: H
authors.lastname: Nishijo
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D003344:Cortical Synchronization; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007092:Imagination / Q000502:physiology*; D008297:Male; D008570:Memory, Short-Term; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D013647:Task Performance and Analysis; D013826:Theta Rhythm