Changes in Cortical Activation Patterns in Language Areas following an Aerobic Exercise Intervention in Older Adults

Abstract

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 assessments 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 postassessment. 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.

Conflict of interest statement

The authors report no financial conflict of interests.

Figures

Figure 1

Difference in VO2 change after 12-week intervention in quantile plots. Means are presented as center green lines. Group differences in VO2 change are significant between the Spin and Balance groups (p < .01).

Figure 2

Group difference in the cognitive battery and in-scanner sematic fluency performance following the 12-week intervention. Sem Flu = semantic verbal fluency (outside scanner); letter flu = letter verbal fluency; scanner response = in-scanner semantic verbal fluency; HVLT = Hopkins Verbal Learning Test. ∗ denotes significant difference at p = .05.

Figure 3

(a) presents a 3D whole-brain rendering of group differences after 3dMVM analysis of post session imaging data between Balance and aerobic Spin group. Color intensity (blue hue) denotes significantly lower levels of activity in aerobic Spin group correcting for multiple comparisons with a voxel-wise threshold level p < .01 holding alpha at .01 for a minimum cluster size of 101 voxels. (b) presents a correlation of VO2 change to change in inferior frontal activity after intervention. This indicates that the greater the VO2 change, the larger the change in right frontal activity. Ordinate axis is VO2 change and abscissa is change in frontal activity. All data is z-normalized.

Figure 4

This figure presents a 3D whole-brain rendering of regression of VO2 change data with fMRI activity across all participants. Particularly in right hemisphere, the greater the VO2 change is in participants, the less likely they were to recruit right lateral frontal and right perisylvian language cortex. Orange color indicates increased fMRI activity with increased VO2 and blue indicates decreased fMRI activity with increased VO2. Data was corrected for multiple comparisons with a voxel-wise threshold level p < .01 holding alpha at 0.02.

Figure 5

This figure presents a 3D whole-brain rendering of regression of in-scanner performance data with fMRI activity across all participants. A positive relationship was found between task performance and greater activity in left hemisphere (represented by orange). Activity in right language cortex was associated with decreased semantic fluency (represented in blue). Data was corrected for multiple comparisons with a voxel-wise threshold level p < .01 holding alpha at 0.02.