Improved Working Memory Following Novel Combinations of Physical and Cognitive Activity

Abstract

Background. In humans, retrospective studies suggest that habitual physical activity (PA) or cognitive activity (CA) can help maintain or improve cognitive function. Similar findings have been reported using physical exercise in animal studies; however, the exercise paradigms differ markedly in duration and frequency, making extrapolation difficult. Here, the authors present a novel PA and CA paradigm that combines voluntary wheel running with Hebb-Williams and radial arm maze (RAM) training. Methods. A total of 57 male Sprague-Dawley rats were divided into 4 treatment groups: the PA, CA, and combined PA and CA groups and sedentary controls. PA (voluntary wheel running) and CA (Hebb-Williams mazes) consisted of a moderate 2 h/d, 5 d/wk treatment paradigm. Results. Animals exposed to a combination of PA and CA made significantly fewer working memory errors and exhibited superior choice accuracy when compared with animals exposed to either PA or CA alone in the 8-arm baited configuration of the RAM. Additional analyses revealed that the cognitive improvements were independent of exercise intensity/duration. Assessment of brain-derived neurotrophic factor (BDNF) levels revealed a significant increase in hippocampal BDNF only in the PA-alone group. Conclusion. A novel combination of PA and CA improves learning and memory abilities independent of activity intensity, BDNF, or phosphorylated cyclic AMP response element binding protein levels. This is the first report of significant changes in cognitive ability using a paradigm involving moderate levels of PA plus cognitive stimulation. An adaptation of this paradigm may be particularly beneficial in slowing the development of mild cognitive impairment and subsequent dementia in elderly people.