title: Associations among imaging measures (2): the association between gray matter concentration and task-induced activation changes.
abstract: The association between functional activation and gray matter (GM) structure has been revealed in clinical studies and studies of aging involving a small number of subjects. The purpose of this study was to investigate the association between functional activation maps and GM structures in young adults who do not show apparent GM atrophy and to investigate in detail the nature of this association using a large number of subjects. We used voxel-by-voxel regression analyses to investigate voxel-by-voxel associations between GM concentration (GMC) and contrast estimate images of brain activity during n-back working memory tasks. Associations were assessed for each voxel after regressing out the effects of age, sex, and mean signal intensity during functional magnetic resonance imaging scanning at each voxel using data from 248 normal, right-handed, young adult subjects. In our study, the concept of "the greater the GMC, the greater the task-related activation increase/task-related activation decrease (or the greater the task-related activation change from baseline)" was true for a wide range of activated and deactivated areas. However, in some minor regions, the other pattern of "the greater the GMC, the smaller the task-related activation increase" was observed. The first pattern is often observed at the borders of GM structures. These findings may have to be taken into consideration when group/individual differences in functional activation are investigated.
authors.affiliation: Department of Advanced Brain Science, Smart Ageing International Research Center, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Taki
authors.forename: Rui
authors.initials: R
authors.lastname: Nouchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hashizume
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sassa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sekuguchi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kotozaki
authors.forename: Seishu
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nagase
authors.forename: Carlos Makoto
authors.initials: CM
authors.lastname: Miyauchi
authors.forename: Ryuta
authors.initials: R
authors.lastname: Kawashima
mesh_terms: D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D055815:Young Adult