Exercise training increases size of hippocampus and improves memory

Abstract

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 randomized 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 mediator of neurogenesis in the dentate gyrus. Hippocampal volume declined in the control group, but higher preintervention fitness partially attenuated the decline, suggesting that fitness protects against volume loss. Caudate nucleus and thalamus volumes were unaffected by the intervention. These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.eterioration of the hippocampus precedes and leads to memory impairment in late adulthood (1, 2). Strategies to fight hippocampal loss and protect against the development of memory impairment has become an important topic in recent years from both scientific and public health perspectives. Physical activity, such as aerobic exercise, has emerged as a promising lowcost treatment to improve neurocognitive function that is accessible to most adults and is not plagued by intolerable side effects often found with pharmaceutical treatments (3). Exercise enhances learning and improves retention, which is accompanied by increased cell proliferation and survival in the hippocampus of rodents (4-6); effects that are mediated, in part, by increased production and secretion of BDNF and its receptor tyrosine kinase trkB (7,8).Aerobic exercise training increases gray and white matter volume in the prefrontal cortex (9) of older adults and increases the functioning of key nodes in the executive control network (10, 11). Greater amounts of physical activity are associated with sparing of prefrontal and temporal brain regions over a 9-y period, which reduces the risk for cognitive impairment (12). Further, hippocampal and medial temporal lobe volumes are larger in higher-fit older adults (13,14), and larger hippocampal volumes mediate improvements in spatial memory (13). Exercise training increases cerebral blood volume (15) and perfusion of the hippocampus (16), but the extent to which exercise can modify the size of the hippocampus in late adulthood remains unknown.To evaluate whether exercise training increases the size of the hippocampus and improves spatial memory, we designed a singleblind, randomized controlled trial in which adults were randomly assigned to receive either moderate-...

Neuroscience and education: prime time to build the bridge

“…Also ripe is the need for a systematic investigation of optimal exercise schedules in school, given the overwhelming evidence that physical exercise benefits cognition through a variety of mechanisms that likely include upregulation of neurotrophic factors and enhancement of hippocampal neurogenesis and size 9 . Notably, exercise and cognition are synergic: although aerobic activity alone leads to an increase in capillary density and neurogenesis, enhanced astrocyte and neuropil volumes only occur when aerobic exercise is combined with environmental enrichment.…”

Structural and functional neuroplasticity in human learning of spatial routes

“…Draganski et al provided some of the first longitudinal evidence of learning-induced structural plasticity in humans by showing voxel-based morphometric changes in the gray matter of bilateral temporal visual motion areas and the left intraparietal sulcus following three months of training on juggling (Draganski et al, 2004). Additional studies of gray matter have suggested neuroplastic changes resulting from intensive training or learning in domains such as medical knowledge (Draganski et al, 2006), spatial memory (Maguire et al, 2006;Woollett and Maguire, 2011), and aerobic exercise (Colcombe et al, 2006;Erickson et al, 2011).…”

Exercise training for neural recovery in a restricted sample of pediatric brain tumor survivors: a controlled clinical trial with crossover of training versus no training

“…6,7 In humans, higher fitness levels predict increased organization of white matter, larger hippocampal volumes, and better cognitive function in healthy children, adolescents, and adults, 8,9 adults with multiple sclerosis, 10 and pediatric brain tumor survivors. 11 Clinical trials have demonstrated that aerobic exercise training can foster brain growth, slow cognitive decline in normal and pathological aging, [12][13][14] and enhance brain and cognitive function in healthy and obese children. 15,16 Given the promising results linking exercise with brain health, it is surprising that limited work has examined its therapeutic effects for brain recovery in pediatric brain tumor survivors.…”