Final Report Summary - REBOOT (Releasing the brakes on adult plasticity)
Age-related cognitive impairments compromise the functional capacity of aging individuals, and create major individual and societal costs. Developing means for preserving and restoring cognitive functioning in old age is therefore of great importance. Cognitive training is one promising route, but results have been disappointing. The main objective of this project was to discover feasible ways to transiently increase brain plasticity in older humans so that the effects of cognitive training can be increased. To achieve this goal, studies combining cognitive training with either pharmacology (L-dopa administration), brain stimulation, or physical exercise in health older humans were conducted. The results show that the brain stimulation (transcranial-direct current) did not improve cognitive performance or the outcomes of cognitive training, demanding a more cautious appraisal of the potential applications of current stimulation. Results from a second intervention study have also shown that subject receiving L-dopa learn slower and improve less on spatial intelligence measures than subjects receiving placebo. The results speak against early pharmacological interventions in older healthy adults to improve cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements. The findings also warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. Finally, the project has provided the first empirical support for a time-critical but advantageous role for increases in peripheral Brain-derived Neurotropic Factor (BDNF) from physical exercise for learning in older adults. These results have clear implications for the design of future multidomain interventions, suggesting that enhancing BDNF release during cognitive training may improve learning and the effects of cognitive training. Acute effects related to physical exercise may be leveraged for improving brain plasticity and for enhancing learning and cognitive performance.