title: Functional relevance of micromodules in the human association cortex delineated with high-resolution FMRI.
abstract: Recent advancement of resting-state functional connectivity magnetic resonance imaging (MRI) has provided a method for drawing boundaries of brain areas. However, it remains to be elucidated how the parcellated areas in the association cortex relate to the spatial extent of the brain activation which ought to reflect a functional unit in the neural network supporting that particular function. To address this issue, in the present study, we first mapped boundaries and 2 adjacent activations in the human inferior frontal cortex, and then examined the spatial relationship between the boundaries and the 2 activations. The boundaries mapped with high-resolution functional magnetic resonance imaging revealed a collection of micromodules, the size of which was approximately only 12 mm on average, much smaller than the Brodmann areas. Each of the 2 activations associated with 2 functions, response inhibition and feedback processing, was smaller in size than the micromodules. By comparing the spatial patterns between the boundaries and the 2 activations, it was revealed that the brain activations were less likely to be located on the boundaries. These results suggest the functional relevance of the areas in the association cortex delineated by the boundary mapping method based on resting-state functional connectivity MRI.
authors.affiliation: Department of Physiology, The University of Tokyo School of Medicine, Bunkyo-ku, Tokyo 113, Japan and.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hirose
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Watanabe
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Wada
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Imai
authors.forename: Toru
authors.initials: T
authors.lastname: Machida
authors.forename: Ichiro
authors.initials: I
authors.lastname: Shirouzu
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyashita
authors.forename: Seiki
authors.initials: S
authors.lastname: Konishi
mesh_terms: D000328:Adult; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D055815:Young Adult