***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Previous work has shown that older adults who evidence increased right inferior frontal gyrus ( IFG ) activity during language tasks show decreased sematic verbal fluency performance . The current study sought to evaluate if an aerobic exercise intervention can alter patterns of brain activity during a semantic verbal fluency task assessed by functional magnetic resonance imaging ( fMRI ) . Thirty-two community-dwelling , sedentary older adults were enrolled to a 12-week aerobic “ Spin ” exercise group or a 12-week nonaerobic exercise control condition ( Balance ) .  Thirty participants completed their assigned intervention ( 16 Spin ; 14 Balance ) with pre- and postintervention assessment s of a semantic verbal fluency task during fMRI and estimated VO2max testing . There was a significant increase in the change scores for estimated VO2max of the Spin group when compared to the Balance group . Semantic verbal fluency output within the scanner was also improved in the Spin group as compared to controls at post assessment . Group fMRI comparisons of IFG activity showed lower activity in the right IFG following the intervention in the aerobic Spin group when compared to the Balance group . Regression analysis of imaging data with change in both estimated VO2max and semantic verbal fluency was negatively correlated with activity in right IFG . The current work is registered as clinical trial with NCT01787292 and NCT02787655 Studies have shown that aerobic exercise has the potential to improve cognition and reduce brain atrophy in older adults . However , the literature is equivocal with regards to the specificity or generality of these effects . To this end , we report results on cognitive function and brain structure from a 6-month training intervention with 60 sedentary adults ( 64–78 years ) r and omized to either aerobic training or stretching and toning control training .  Cognitive functions were assessed with a neuropsychological test battery in which cognitive constructs were measured using several different tests . Freesurfer was used to estimate cortical thickness in frontal regions and hippocampus volume . Results showed that aerobic exercisers , compared to controls , exhibited a broad , rather than specific , improvement in cognition as indexed by a higher “ Cognitive score , ” a composite including episodic memory , processing speed , updating , and executive function tasks ( p = 0.01 ) . There were no group differences in cortical thickness , but additional analyses revealed that aerobic fitness at baseline was specifically related to larger thickness in dorsolateral prefrontal cortex ( dlPFC ) , and hippocampus volume was positively associated with increased aerobic fitness over time . Moreover , “ Cognitive score ” was related to dlPFC thickness at baseline , but changes in “ Cognitive score ” and dlPFC thickness were associated over time in the aerobic group only . However , aerobic fitness did not predict dlPFC change , despite the improvement in “ Cognitive score ” in aerobic exercisers . Our interpretation of these observations is that potential exercise-induced changes in thickness are slow , and may be undetectable within 6-months , in contrast to change in hippocampus volume which in fact was predicted by the change in aerobic fitness . To conclude , our results add to a growing literature suggesting that aerobic exercise has a broad influence on cognitive functioning , which may aid in explaining why studies focusing on a narrower range of functions have sometimes reported mixed results The current study examined how a r and omized one-year aerobic exercise program for healthy older adults would affect serum levels of brain-derived neurotrophic factor ( BDNF ) , insulin-like growth factor type 1 ( IGF-1 ) , and vascular endothelial growth factor ( VEGF ) - putative markers of exercise-induced benefits on brain function . The study also examined whether ( a ) change in the concentration of these growth factors was associated with alterations in functional connectivity following exercise , and ( b ) the extent to which pre-intervention growth factor levels were associated with training-related changes in functional connectivity . In 65 participants ( mean age=66.4 ) , we found that although there were no group-level changes in growth factors as a function of the intervention , increased temporal lobe connectivity between the bilateral parahippocampus and the bilateral middle temporal gyrus was associated with increased BDNF , IGF-1 , and VEGF for an aerobic walking group but not for a non-aerobic control group , and greater pre-intervention VEGF was associated with greater training-related increases in this functional connection . Results are consistent with animal models of exercise and the brain , but are the first to show in humans that  exercise-induced increases in temporal lobe functional connectivity are associated with changes in growth factors and may be augmented by greater baseline VEGF BACKGROUND Greater hippocampal volume is observed in healthy older adults after short-term structured exercise . Whether long-term exposure to real-world physical activity ( PA ) programs has similar effects for sedentary older adults with impaired mobility and comorbid conditions is not known . HYPOTHESIS A long-term moderate intensity regimen of PA is related to larger volume of the hippocampus in older adults at risk for mobility disability . We further explore whether these associations are modified by factors known to be related to dementia . METHODS Twenty-six sedentary adults at risk for mobility disability participated in a 24-month r and omized intervention program of physical activity ( PA , N = 10 , age : 74.9 years , 7 women ) or health education ( HE , N = 16 , age : 76.8 years , 14 women ) . Volumes of total hippocampus , dentate gyrus , and cornu ammonis were measured at baseline and at 24-month follow-up using 7-Tesla magnetic resonance imaging . Between-group volumetric differences at 24 months were adjusted for sessions attended and baseline volumes . The contribution of each dementia-related factor was tested separately for education , APOE , diabetes , cardiovascular diseases , white matter hyperintensities , and brain atrophy . RESULTS Between-group differences were significant for left hippocampus , left cornu ammonis , and right hippocampus . Adjustment for regional baseline volume attenuated the associations to statistically nonsignificant for right hippocampus and left conru ammonis ; associations for left hippocampus were robust for all adjustments . Results were similar after adjustment for dementia-related factors . CONCLUSIONS In this group of sedentary older adults there was a hippocampal response to a long-term program of moderate-intensity PA . Future studies should examine whether hippocampal response could explain the beneficial effects of PA on cognition for vulnerable older adults Age-related  cognitive decline  is a significant public health concern . Recently , non-pharmacological methods , such as physical activity and mental training practice s , have emerged as promising low-cost methods to slow the progression of age-related memory decline . In this study , we investigated if Tai Chi Chuan ( TCC ) and Baduanjin modulated the fractional amplitude of low-frequency fluctuations ( fALFF ) in different frequency b and s ( low-frequency : 0.01–0.08 Hz ; slow-5 : 0.01–0.027 Hz ; slow-4 : 0.027–0.073 Hz ) and improved memory function .  Older adults were recruited for the r and omized study . Participants in the TCC and Baduanjin groups received 12 weeks of training ( 1 h/day for 5 days/week ) . Participants in the  control group received basic health education . Each subject participated in memory tests and fMRI scans at the beginning and end of the experiment . We found that compared to the control group : ( 1 ) TCC and Baduanjin groups demonstrated significant improvements in memory function ; ( 2 ) TCC  increased fALFF in the dorsolateral prefrontal cortex ( DLPFC ) in the slow-5 and low-frequency b and s ; and ( 3 ) Baduanjin increased fALFF in the medial PFC in the slow-5 and low-frequency b and s. This increase was positively associated with memory function improvement in the slow-5 and low-frequency b and s across the TCC and Baduanjin groups . Our results suggest that TCC and Baduanjin may work through different brain mechanisms to prevent memory decline due to aging BACKGROUND Cognitive decline among seniors is a pressing health care issue . Specific exercise training may combat cognitive decline . We compared the effect of once-weekly and twice-weekly resistance training with that of twice-weekly balance and tone exercise training on the performance of executive cognitive functions in senior women . METHODS In this single-blinded r and omized trial , 155 community-dwelling women aged 65 to 75 years living in Vancouver were r and omly allocated to once-weekly ( n = 54 ) or twice-weekly ( n = 52 ) resistance training or twice-weekly balance and tone training ( control group ) ( n = 49 ) . The primary outcome measure was performance on the Stroop test , an executive cognitive test of selective attention and conflict resolution . Secondary outcomes of executive cognitive functions included set shifting as measured by the Trail Making Tests ( parts A and B ) and working memory as assessed by verbal digit span forward and backward tests . Gait speed , muscular function , and whole-brain volume were also secondary outcome measures . RESULTS Both resistance training groups significantly improved their performance on the Stroop test compared with those in the balance and tone group ( P < or = .03 ) . Task performance improved by 12.6 % and 10.9 % in the once-weekly and twice-weekly resistance training groups , respectively ; it deteriorated by 0.5 % in the balance and tone group . Enhanced selective attention and conflict resolution was significantly associated with increased gait speed . Both resistance training groups demonstrated reductions in whole-brain volume compared with the balance and tone group at the end of the study ( P < or = .03 ) . CONCLUSION Twelve months of once-weekly or twice-weekly resistance training benefited the executive cognitive function of selective attention and conflict resolution among senior women . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00426881 BACKGROUND The present study examined whether aerobic fitness training of older humans can increase brain volume in regions associated with age-related decline in both brain structure and cognition . METHODS Fifty-nine healthy but sedentary community-dwelling volunteers , aged 60 - 79 years , participated in the 6-month r and omized clinical trial . Half of the older adults served in the aerobic training group , the other half of the older adults participated in the toning and stretching control group .  Twenty young adults served as controls for the magnetic resonance imaging ( MRI ) , and did not participate in the exercise intervention . High spatial resolution estimates of gray and white matter volume , derived from 3D spoiled gradient recalled acquisition MRI images , were collected before and after the 6-month fitness intervention . Estimates of maximal oxygen uptake ( VO2 ) were also obtained . RESULTS Significant increases in brain volume , in both gray and white matter regions , were found as a function of fitness training for the older adults who participated in the aerobic fitness training but not for the older adults who participated in the stretching and toning ( nonaerobic ) control group . As predicted , no significant changes in either gray or white matter volume were detected for our younger participants . CONCLUSIONS These results suggest that cardiovascular fitness is associated with the sparing of brain tissue in aging humans . Furthermore , these results suggest a strong biological basis for the role of aerobic fitness in maintaining and enhancing central nervous system health and cognitive functioning in older adults Physical exercise , particularly aerobic exercise , is documented as providing a low cost regimen to counter well-documented cognitive declines including memory , executive function , visuospatial skills , and processing speed in normally aging adults . Prior aging studies focused largely on the effects of medium to long term ( > 6 months ) exercise training ; however , the shorter term effects have not been studied . In the present study , we examined changes in brain blood flow , cognition , and fitness in 37 cognitively healthy sedentary adults ( 57–75 years of age ) who were r and omized into physical training or a wait-list control group .  The physical training group received supervised aerobic exercise for 3 sessions per week 1 h each for 12 weeks . Participants ' cognitive , cardiovascular fitness and resting cerebral blood flow ( CBF ) were assessed at baseline ( T1 ) , mid ( T2 ) , and post-training ( T3 ) . We found higher resting CBF in the anterior cingulate region in the physical training group as compared to the control group from T1 to T3 . Cognitive gains were manifested in the exercise group 's improved immediate and delayed memory performance from T1 to T3 which also showed a significant positive association with increases in both left and right hippocampal CBF identified earlier in the time course at T2 . Additionally , the two cardiovascular parameters , VO2 max and rating of perceived exertion ( RPE ) showed gains , compared to the control group . These data suggest that even shorter term aerobic exercise can facilitate neuroplasticity to reduce both the biological and cognitive consequences of aging to benefit brain health in sedentary adults The hippocampus shrinks in late adulthood , leading to impaired memory and increased risk for dementia . Hippocampal and medial temporal lobe volumes are larger in higher-fit adults , and physical activity training increases hippocampal perfusion , but the extent to which aerobic exercise training can modify hippocampal volume in late adulthood remains unknown . Here we show , in a r and omized controlled trial with 120 older adults , that aerobic exercise training increases the size of the anterior hippocampus , leading to improvements in spatial memory .  Exercise training increased hippocampal volume by 2 % , effectively reversing age-related loss in volume by 1 to 2 y. We also demonstrate that increased hippocampal volume is associated with greater serum levels of BDNF , a 
    Output:
    
This systematic review indicates that older adults involved in exercise training  may derive general benefits to brain health , as reflected by intervention-induced changes in brain structure and function .
However , such benefits are dependent upon the dose of the exercise intervention .