Functional and Diffusion-Based Microstructural Correlates in Cortical and Subcortical Substrates of Motor Performance of a Complex Visuomotor Task in Middle-Aged Adults.

Background: Cognitive training offers a potential approach for the prevention of cognitive decline in later life. Repetition of targeted exercises may improve, or at least preserve, both specific domain and general cognitive abilities by strengthening neural connections and promoting neuroprotective processes within brain networks. Importantly, middle-aged adults have been omitted from the cognitive training literature. In this experiment, we investigated short-term training (1 session) on a perceptual-cognitive-motor task in middle-aged adults. Furthermore, we examined the functional and structural neural correlates of this training.

Methods: Twenty-one healthy middle-aged adults between the age of 40 and 50 years underwent one scanning session during which they learned and performed the perceptual-cognitive-motor task. We compared performance and functional imaging on the Early and Late Learning phases of the task. We used diffusion Magnetic Resonance Imaging (MRI) to examine baseline microstructural variation in the brain in relation to training outcome. The diffusion indices included fractional anisotropy (FA), mean diffusivity (MD), neurite density index (NDI), and orientation dispersion index (ODI).

Results: We found a significant improvement in performance following training on the task. The improvement correlated with gaming experience, but not with impulsivity. There were also significant training-induced changes in functional activity in cerebellar, cortical and subcortical brain regions. Furthermore, significant correlations were found between the diffusion indices of FA, MD, and ODI and training outcome.

Conclusions: These results suggest fast reorganisation of functional activity in the middle-aged brain, and that individual variation in brain microstructure correlates with fast visuo-motor task performance gains.