title: Motor map reliability and aging: a TMS/fMRI study.
abstract: This study compared the reliability of motor maps over 3 sessions from both neuronavigated transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) data between younger and older adults. Seven younger (ages 19-31) and seven older (ages 64-76) adults participated in three joint TMS/fMRI assessment sessions separated by 7 or 14 days. Sessions involved mapping of the right first dorsal interosseous muscle using single-pulse TMS immediately followed by block-design fMRI scanning involving volitional right-hand index finger to thumb oppositional squeeze. Intersession reliability of map volume, evaluated by intraclass correlation and Jaccard Coefficient between testing sessions, was more consistent for younger adults in both fMRI and TMS. A positive correlation was evidenced between fMRI and TMS map volumes and Jaccard Coefficients indicating spatial consistency across sessions between the two measures. Comparisons of map reliability between age groups showed that younger adults have more stable motor maps in both fMRI and TMS. fMRI and TMS maps show consistency across modalities. Future interpretation of motor maps should attempt to account for potential increased variability of such mapping in older age groups. Despite these age group differences in reliability, fMRI and TMS appear to offer consistent and complementary information about cortical representation of the first dorsal interosseous muscle.
authors.affiliation: Department of Veterans Affairs Rehabilitation Research and Development Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA. kmcgrego@phhp.ufl.edu
authors.forename: Keith M
authors.initials: KM
authors.lastname: McGregor
authors.forename: Haley
authors.initials: H
authors.lastname: Carpenter
authors.forename: Erin
authors.initials: E
authors.lastname: Kleim
authors.forename: Atchar
authors.initials: A
authors.lastname: Sudhyadhom
authors.forename: Keith D
authors.initials: KD
authors.lastname: White
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Butler
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kleim
authors.forename: Bruce
authors.initials: B
authors.lastname: Crosson
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001931:Brain Mapping; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D005385:Fingers / Q000294:innervation; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply* / Q000502:physiology*; D010100:Oxygen; D011597:Psychomotor Performance / Q000502:physiology; D015203:Reproducibility of Results; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
chemical_list: D010100:Oxygen