The Neural Correlates of Physical and Cognitive Training in the Prevention of Age-Related Cognitive Decline: A Review

Review Article

Gerontol & Geriatr Res. 2016; 2(1): 1006.

The Neural Correlates of Physical and Cognitive Training in the Prevention of Age-Related Cognitive Decline: A Review

Angeles Garcia*, Luedke Angela, Itorralba Justine, Fernandez-Ruiz Juan

Department of Medicine and Neuroscience Centre, Queen’s University, Canada

*Corresponding author: Angeles Garcia, Department of Medicine and Neuroscience Centre, Queen’s University, 340 Union Street, Rm1-175 Kingston, ON, Canada

Received: November 20, 2015; Accepted: February 18, 2016; Published: February 22, 2016


Physical activity and cognitive training are heavily studied nonpharmacological interventions for the deceleration of age-related cognitive decline and the prevention of dementia. Epidemiological studies and randomized control trials have found evidence that both of these lifestyle modifications administered separately or together, may provide improvements in overall cognition. While evidence in support of physical and cognitive activity is vast, the neural underpinnings of this training-induced cognitive improvement have yet to be fully elucidated. This review will attempt to combine the most recent research regarding the neural correlates of cognitive enhancement driven by physical and cognitive training interventions. A heavy focus will be placed on structural brain volume, functional MRI, functional connectivity, and white matter integrity changes before and after physical or cognitive training interventions.

Keywords: Exercise interventions; Cognitive training; Healthy aging; Neural plasticity


Healthy cognitive aging is associated with many neurophysiological and cognitive changes. Various aspects of cognition demonstrate agerelated declines, including memory, attention, and processing speed [1]. Additionally, healthy aging is associated with neuroanatomical changes in both gray and white matter, functional connectivity patterns, and functional brain activations that can all be detected using various imaging techniques. Therefore, interventions decelerating age-related declines are needed, especially at its earliest stages, to prevent or postpone subsequent conversion to early dementia and Mild Cognitive Impairment (MCI).

Of these interventions, cognitive training and physical activity have been the most heavily studied. Increased physical activity has not only been linked to health benefits [2], but also to the maintenance or enhancement of cognitive functioning [3,4]. Increasing use of technology amongst seniors combined with the rising popularity of programs like Lumosity and Brain Age, have led to heightened interest in the efficacy of these personalized cognitive training programs. Recently, research concerning physical activity and cognitive training in the elderly has focused on determining the neural underpinnings of lifestyle-induced improvements. We reviewed recent Randomized Controlled Trials (RCTs) in the healthy elderly population with a focus on the neural correlates of training-induced changes.


We searched electronic databases (PubMed, Web of Science, and Medline) for RCTs investigating the impact of physical exercise and cognitive training on cognition and the brain. Search terms included: healthy aging, cognition, exercise, physical activity, exercise training, brain, white matter, grey matter, cognitive aging, cognitive training, cognitive stimulation, intellectual stimulation, intellectual activity, and brain games. Due to discrepancy in the way different studies define “cognitive training,” search terms including the words brain games, intellectual, stimulation, and activity were used to prevent exclusion of any potentially relevant RCTs.

Since the focus of our review was on interventions in healthy aging, articles had to include cognitively normal elderly treatment and control groups with participants aged 50 and above, include both a cognitive and neurophysiological measure, and have at least 10 participants per intervention group. Additionally, each RCT had to have a clearly defined intervention protocol with outcome measures collected at least before and after the intervention administration. In the interest of novelty, RCTs conducted before 2004 were excluded.

While there were a large number of studies testing the efficacy of cognitive training and physical exercise in healthy aging, studies obtaining both behavioral and neurophysiological measures preand post-intervention were not as prevalent. Furthermore, the types, frequencies, and durations of these interventions were markedly variable between studies, which had the potential to introduce a fair amount of bias when comparatively analyzing these randomized control trials. Therefore, since there were so few of these types of RCTs found, we did not include any parameters quantifying or assessing the risk of bias of individual studies.


Our initial database search yielded a total of 8587 records. After eliminating irrelevant studies, duplicates, and studies that were published before 2004, we were left with 364 records. Those that were considered irrelevant or out of scope were review articles, studies that applied interventions to the clinical population (i.e. Alzheimer’s Disease, Mild Cognitive Impairment, Parkinson’s Disease), and studies that contained an intervention group with a mean age below sixty. These records were then preliminarily screened on the basis of their title and abstract. This preliminary screening yielded 199 RCTs for further analysis and eliminated 165 records that did not meet the aforementioned eligibility criteria and did not contain a training intervention, neurophysiological outcome measure, or cognitive outcome measure. We then further examined 22 RCTs closely for quality, and they had to include clearly defined training intervention descriptions, and both neurophysiological and cognitive outcome measures collected at least pre- and post-intervention. This final inquiry left a total of 22 RCTs for qualitative analysis.


Structural volume changes

Physical exercise: The link between grey matter volume and exercise has been studied in several RCTs, with promising results (Table 1). Higher levels of physical exercise are associated with increased grey matter volume in prefrontal areas [5,6], temporal lobes including the hippocampus [6-8], and in white matter [7]. One study of healthy adults aged 60 -79 found that aerobic exercise training for 6 months was enough to increase gray matter in areas of the frontal and temporal lobes, as well as the anterior portion of the Corpus Callosum (CC) compared to a non-aerobic control group (toning and stretching) [9]. Another RTC involving 120 sedentary adults over the age of 55 comparing an aerobic (walking) program with a stretching and toning control program, found that a year-long aerobic exercise intervention was enough to offset the normal age related shrinking of the anterior portion of the hippocampus [10]. Furthermore, despite no group differences in spatial memory post-intervention, change in hippocampal volume correlated positively with VO2, a measure of peak oxygen consumption, and spatial memory. Serum Brain Derived Neurotrophic Factor (BDNF) levels, a neurotrophin linked to plasticity also correlated with bilateral hippocampal volume changes in the exercise group [10]. However, the type of exercise may be an important factor to consider, as there is inconsistency in the literature as to the beneficial effects of aerobic versus non- aerobic exercise.