**3. Method**

#### **3.1 Search strategy**

The Medline (1996 – 04/2011) database was searched for original research articles in English that met the following criteria. (a) 'brain training', 'cognitive training', 'cognitive

Neuroimaging Outcomes of Brain Training Trials 419

Table 1. Summary of brain training interventions with MRI outcomes.

intervention', 'cognitive exercise', 'mental exercise', 'cognitive activity' or 'cognitive stimulation', and (b) 'individuals', 'adults', 'persons', 'subjects', but no 'children' or 'teenagers', and (c) 'Magnetic Resonance Image', 'MRI' or 'brain scans'. Combined intervention, subject, and method terms were searched across all fields and produced 144 studies. The title and abstract of these studies were reviewed to identify potentially relevant trials, and these were supplemented by manual checking through reference lists of published reports.
