title: Functional language networks in sedentary and physically active older adults.
abstract: Functional magnetic resonance imaging (fMRI) studies have identified consistent age-related changes during various cognitive tasks, such that older individuals display more positive and less negative task-related activity than young adults. Recently, evidence shows that chronic physical exercise may alter aging-related changes in brain activity; however, the effect of exercise has not been studied for the neural substrates of language function. Additionally, the potential mechanisms by which aging alters neural recruitment remain understudied. To address these points, the present study enrolled elderly adults who were either sedentary or physically active to characterize the neural correlates of language function during semantic fluency between these groups in comparison to a young adult sample. Participants underwent fMRI during semantic fluency and transcranial magnetic stimulation to collect the ipsilateral silent period, a measure of interhemispheric inhibition. Results indicated that sedentary older adults displayed reductions in negative task-related activity compared to the active old group in areas of the attention network. Longer interhemispheric inhibition was associated with more negative task-related activity in the right and left posterior perisylvian cortex, suggesting that sedentary aging may result in losses in task facilitatory cortical inhibition. However, these losses may be mitigated by regular engagement in physical exercise.
authors: Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0664, USA. zzlatar@ucsd.edu
authors: Zvinka Z
authors: ZZ
authors: Zlatar
authors: Stephen
authors: S
authors: Towler
authors: Keith M
authors: KM
authors: McGregor
authors: Joseph M
authors: JM
authors: Dzierzewski
authors: Andrew
authors: A
authors: Bauer
authors: Stephanie
authors: S
authors: Phan
authors: Matthew
authors: M
authors: Cohen
authors: Michael
authors: M
authors: Marsiske
authors: Todd M
authors: TM
authors: Manini
authors: Bruce
authors: B
authors: Crosson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D010100:Oxygen / Q000097:blood; D012660:Semantics; D050781:Transcranial Magnetic Stimulation
chemical_list: D010100:Oxygen