Design The present study is designed as a randomized stratified controlled trial including two intervention groups, one waiting group (children with a history of cancer [both CNS+ and CNS-] and a healthy control group (matched for age and gender). Some children of the patient group will be allocated to a waiting-control group to determine the training effects (their training starts later on). After random assignment to the respective conditions, the interventional material (XBOX or computer), will be installed at the participants home. Thereby, a supervised first training session will take place. The executive functions before and after as well as more details on the effects of a single intervention session (on enjoyment, arousal etc.) will be examined. Subsequently, the respective group will either follow a standardized, computerized working memory training or a physical training. Neuropsychological assessment will be carried out before the intervention / training and re-performed with all participants at the end of the memory training or physical training and at 6 months posttraining. Structural and functional imaging will be performed prior and shortly after working memory training and physical training. A 3 Tesla whole body MRI system will be used (Siemens; Erlangen, Germany). Anatomical imaging will be obtained using a sequence for T1 weighted structural brain imaging with whole brain coverage. Structural connectivity images will be acquired by using a q-ball sequence, functional connectivity will be measured by using a multiband echo planar imaging sequence (MB EPI). Pre- and post-processing of the structural data will be performed using SPM8 (Welcome Departement of Imaging Neuroscience, London) and MATLAB programs (MATLAB version 8.2). In order to perform functional connectivity analyses, the CONN fMRI connectivity toolbox 13.1 (Whitfield-Gabrieli & Nieto-Castanon, 2012) is used. The fractional anisotropy maps are provide by the Siemens software and can be directly used for further statistical evaluation.