 Introduction  Method  Result  Disscussion

 Deterioration of the hippocampus leads to memory impairment in late adulthood.  Physical activity, such as aerobic exercise, has emerged as a promising low-cost treatment to improve neurocognitive function.

 Exercise enhances learning and improves retention, which is accompanied by increased cell proliferation and survival in the hippocampus.  Effects that are mediated, in part, by increased production and secretion of BDNF and its receptor tyrosine kinase trkB.

 BDNF (Brain-derived neurotrophic factor, 腦衍生神經滋長因子 ) › 一種廣泛分布在中樞神經的的蛋白質，是大腦中重 要的神經營養因子。 › 主要功能為在腦部調控神經細胞的發育、存活及突 觸的成形，並調控神經傳導物質及細胞內訊息的傳 遞。 › 存在海馬迴的 BDNF 與記憶和學習有關係。

 Aerobic exercise training increases gray and white matter volume in the prefrontal cortex of older adults.  Further, hippocampal and medial temporal lobe volumes are larger in higher-fit older adults. › larger hippocampal volumes mediate improvements in spatial memory

 Exercise training increases cerebral blood volume and perfusion of the hippocampus. › but the extent to which exercise can modify the size of the hippocampus remains unknown.

 To evaluate whether exercise training increases the size of the hippocampus and improves spatial memory › Aerobic exercise VS. stretching exercises.  Prediction: 1. 1 y of moderate-intensity exercise would increase the size of the hippocampus 2. change in hippocampal volume would be associated with increased serum BDNF and improved memory function.

 Participant 120 participants had complete MR data from all three sessions and were included in the analyses. › Eligible participants › Baseline assessment  blood draw, MR session, fitness assessment.

 Procedure

 Fitness Assessments VO 2 max( 最大攝氧量 ) › 也稱為「氧極限」，當運動強度增加到一定限度 後，人體的攝氧和用氧能力不再繼續增加。此時 的攝氧量就是最大攝氧量。 VO 2 max 是用來反映 運動員的有氧能力和運動潛能的最重要的指標。  MRI session › the start of the intervention › after 6 months › after 1 year

 Training Protocol › Aerobic exercise condition  40 min per session  Encouraged to target heart zone( 目標心跳區 ) › Stretching and toning control condition  Muscle-toning exercises  Balance-improving exercises  yoga sequence, one exercise of their choice  Encouraged to increase the intensity by using more weight or adding more repetitions

 Spatial Memory Paradigm › a computerized spatial memory task › Baseline, after 6 months, after one year  Serum BDNF Assay › Baseline, after one year

 Aerobic Exercise Training Selectively Increases Hippocampal Volume › Aerobic exercise group  increase in volume of the left and right hippocampus › Stretching control group  decrease in volume of the left and right hippocampus

 Aerobic Exercise Training Selectively Increases Hippocampal Volume › Anterior hippocampus  Selective increase in aerobic exercise group  Selective decline in Stretching control group  where cell proliferation occurs.  mediate acquisition of spatial memory and show more age-related atrophy. › Posterior hippocampus  no significant change in either group

 Aerobic Exercise Training Selectively Increases Hippocampal Volume › Region specificity: by examining thalamus and caudate nucleus that served as control.  Nonsignificant change

 Aerobic Exercise Training Selectively Increases Hippocampal Volume › hippocampus is modifiable in late adulthood › moderate-intensity aerobic exercise is effective at reversing volume loss › influencing the anterior hippocampus but not the posterior hippocampus or the thalamus or caudate nucleus

 Changes in Fitness Are Associated with Increased Hippocampal Volume › The intervention was effective at increasing aerobic fitness levels (VO 2 max) › The difference between the groups is significant.

 Changes in Fitness Are Associated with Increased Hippocampal Volume › Association between changes in aerobic fitness levels and changes in hippocampal volume  Both hemisphere  larger changes in fitness translate to larger changes in volume  Both anterior and posterior  aerobic fitness have a global influence on hippocampal volume

 Changes in Fitness Are Associated with Increased Hippocampal Volume › if higher physical fitness is protective against the loss of brain tissue  stretching group  results partially consistent with this prediction  High level baseline→ left anterior hippocampus

 BDNF Is Associated with Changes in Hippocampal Volume › The aerobic exercise group did not demonstrate greater changes in BDNF. › Association between changes in BDNF of aerobic group and changes in hippocampal volume  Both hemisphere  anterior but not posterior

 Hippocampal Volume Is Related to Improvements in Spatial Memory › Both groups showed improvements in memory and response times  No significant change between two groups › In the aerobic exercise group, increased hippocampal volume was related to improvements in memory performance.

1. Hippocampal volume shrinks 1–2% annually in older adults without dementia 2. Loss of volume increases the risk for developing cognitive impairment  Results of stretching group consistent with this pattern: 1.4% decline in a year  The loss of hippocampal volume in late adulthood is not inevitable and can be reversed with moderate-intensity exercise.

 Selectivity : influencing only the anterior hippocampus and neither the thalamus nor the caudate nucleus.  BDNF : mediator of neurogenesis, critical in memory formation.  Proliferation might explain increased hippocampal volume and improvements in memory after exercise.

 Anterior hippocampus : spatial memory acquisition, exacerbated age-related atrophy.  less age-related decay might also be less amenable to growth.  the hippocampus remains plastic in late adulthood.  Aerobic exercise is neuroprotective and that starting an exercise later in life is useful for either enhancing cognition or augmenting