Table 1.
Evidence for mechanisms of PA at Level 2 of analysis.
| Lead author | Year | Sample | Mechanistic finding | Type mediation |
|---|---|---|---|---|
| Albinet | 2014 | 34 older adults (all female) | Increases in cerebral oxygen responses in the right DLPFC partially mediate relationship between aerobic fitness and executive control performance | Statistical |
| Chaddock | 2010 | 49 preadolescent children | Hippocampal volume mediates relationship between aerobic fitness and relational memory | Statistical |
| Chaddock-Heyman | 2013 | 23 preadolescent children | Increases in prefrontal activation and executive functioning following a 9-month aerobic exercise intervention | Experimental |
| Colcombe | 2004 | 41 older adults (study 1); 29 older adults (study 2) | Greater activation in prefrontal, parietal, and anterior cingulate cortex, and well as increased cognitive control performance in higher aerobically fit (Study 1) or aerobically trained (Study 2) individuals | Statistical (Study 1); Experimental (Study 2) |
| Erickson | 2009 | 165 older adults | Hippocampal volume mediates relationship between cardiorespiratory fitness and spatial memory | Statistical |
| Erickson | 2011 | 120 older adults | Volume of the hippocampus and memory performance increase following a 12-month aerobic exercise intervention | Experimental |
| Hillman | 2014 | 221 preadolescent children | Frontal activation, cognitive inhibition, and flexibility increases following 9-month aerobic exercise intervention | Experimental |
| Hyodo | 2015 | 60 male older adults | Activation of left dorsolateral prefrontal cortex mediates relationship between fitness and cognitive control | Statistical |
| Kamijo | 2011 | 43 preadolescent children | Increases in cognitively relevant frontal ERP component (CNV) and in working memory following a 9-month aerobic exercise intervention | Experimental |
| Kraft | 2014 | 43 overweight children | Activity increases in the anterior cingulate cortex and decreases in precentral gyrus and parietal cortex following 8-month aerobic exercise intervention; Improved cognitive control performance | Experimental ∗No group × Time interactions for any neurocognitive outcome |
| Krogh | 2014 | 79 clinically depressed older adults | Positive association between change in hippocampal volume and changes in memory following a 3-month aerobic exercise intervention | Experimental ∗Issues with adherence; no group × Time interactions |
| Maass | 2015 | 40 older adults | Hippocampal volume, perfusion, and memory increases following a 3-month aerobic exercise intervention; Changes in perfusion statistically mediate relationship between volume and memory | Experimental and Statistical |
| Makizako | 2015 | 310 older adults with MCI | Hippocampal volume mediates the association between PA and memory in older adults with MCI | Statistical |
| Oberlin | 2016 | 241 older adults across two studies | White matter integrity mediates relationship between fitness and spatial working memory | Statistical |
| Pajonk | 2010 | 24 schizophrenic patients | Hippocampal volume and short-term memory improve following 3-month aerobic exercise intervention; Changes in volume correlate with changes in memory | Experimental |
| Ruscheweyh | 2012 | 62 older adults | Positive association between changes in PA and episodic memory following a 6 months mixed-intensity intervention no longer significant after accounting for the variance associated with change in anterior cingulate gray matter volume | Experimental ∗No group × Time interactions |
| Ten Brinke | 2015 | 86 female older adults | Hippocampal volume increases following 6-month aerobic exercise intervention. Changes in volume negatively associated with changes in short-term memory | Experimental |
| Verstynen | 2012 | 179 older adults | Volume of the caudate nucleus mediates relationship between fitness and cognitive flexibility | Statistical |
| Voss | 2010 | 62 older adults | Connectivity of large-scale brain networks and executive functioning improve following 6-month aerobic exercise intervention; changes in connectivity correlate with changes in executive functioning. | Experimental |
| Voss | 2013a | 70 older adults | Improved fitness is associated with changes in prefrontal and temporal white matter integrity following a 12-month aerobic exercise intervention; no changes in short-term memory performance reported between groups; no mediation model could be tested | Experimental ∗No group × Time interaction for neurocognitive outcome |
| Weinstein | 2012 | 142 older adults | Volume of prefrontal cortex mediates the relationship between cardiorespiratory fitness and working memory, as well as that between fitness and inhibitory control | Statistical |
| Wong | 2015 | 128 older adults | Greater anterior cingulate cortex activation mediates relationship between fitness and dual task performance | Statistical |