Publication Date

2016

Abstract

Physical and cognitive exercise may prevent or delay dementia in later life but the neural mechanisms underlying these therapeutic benefits are largely unknown. We examined structural and functional magnetic resonance imaging ( MRI ) brain changes after 6 months of progressive resistance training ( PRT ), computerized cognitive training ( CCT ) or combined intervention. A total of 100 older individuals ( 68 females, average age=70.1, s.d.±6.7, 55–87 years ) with dementia prodrome mild cognitive impairment were recruited in the SMART ( Study of Mental Activity and Resistance Training ) Trial. Participants were randomly assigned into four intervention groups: PRT+CCT, PRT+SHAM CCT, CCT+SHAM PRT and double SHAM. Multimodal MRI was conducted at baseline and at 6 months of follow-up ( immediately after training ) to measure structural and spontaneous functional changes in the brain, with a focus on the hippocampus and posterior cingulate regions. Participants’ cognitive changes were also assessed before and after training. We found that PRT but not CCT significantly improved global cognition ( F( 90 )=4.1, P < 0.05 ) as well as expanded gray matter in the posterior cingulate ( Pcorrected < 0.05 ), and these changes were related to each other ( r=0.25, P=0.03 ). PRT also reversed progression of white matter hyperintensities, a biomarker of cerebrovascular disease, in several brain areas. In contrast, CCT but not PRT attenuated decline in overall memory performance ( F( 90 )=5.7, P < 0.02 ), mediated by enhanced functional connectivity between the hippocampus and superior frontal cortex. Our findings indicate that physical and cognitive training depend on discrete neuronal mechanisms for their therapeutic efficacy, information that may help develop targeted lifestyle-based preventative strategies.

Document Type

Open Access Journal Article

Access Rights

Open Access

Notes

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if thematerial is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/

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