A-16 Free Communication/Slide - Cognitive Function and Neurobiology: MAY 27, 2009 9:30 AM - 10:30 AM ROOM: 4C3
Hippocampal volume and memory-based function are reduced by age and disease. Aerobic exercise training results in augmented brain volumes, improved cognitive test performance and altered task-related cortical activity in older adults, but it is unclear whether increased cardiorespiratory fitness directly affects the hippocampus.
PURPOSE: To determine the direct effects of exercise training on the hippocampus in healthy humans.
METHODS: We examined the effect of 10 weeks of supervised 3 day/week aerobic exercise training on hippocampal volume (T1-weighted magnetic resonance imaging (MRI)) and hippocampal blood oxygen level dependent (BOLD) activation (functional MRI during two hippocampally-mediated tasks, the Figural Recognition Memory and Virtual Morris Water Tasks) in 20 healthy men and women. Hippocampal measures as well as cardiopulmonary fitness (VO2max) were assessed before and after the training protocol.
RESULTS: Following 10 weeks of exercise training, subjects exhibited a significant (p <0.05) improvement in VO2max (Group means ± SD: 32.4 ± 7.5 to 35.6 ± 7.9 mL/kg/min). There was no overall change (both p > 0.05) in either left or right hippocampal volume with exercise training. However, there was a significant (r2 = 0.44; p = 0.02) and positive relation between the change in cardiorespiratory fitness and the change in right hippocampal volume following exercise training. This relation was marginally significant in the left hippocampus (r2 = 0.32; p = 0.06). Hippocampal BOLD activation during the encoding phase of the Figural Memory Test as well as the Morris Virtual Water Maze task was significantly reduced (p < 0.01 and 0.05, respectively) in subjects following exercise training. Subjects also demonstrated a significant memory performance improvement with exercise training, as the number of correctly identified targets on the Figural Memory Task increased (14.1 ± 3.7 vs. 16.1 ± 1.8 targets; p = 0.02) and the number of incorrect moves to the platform in the Morris Virtual Water Maze task decreased (20.3 ± 10.6 vs. 12.8 ± 8.2 incorrect moves; p < 0.01) following training.
CONCLUSION: These results suggest that aerobic exercise is a potentially promising therapy with which to affect hippocampal structure, activation and function.
Supported by a Hartford Hospital Open Competition Grant (#123252).