The present proposal seeks to uncover the markers and mechanisms underlying changes in brain and cognitive behavior throughout the lifespan, and whether, and how, we ourselves can initiate, enhance or slow such changes. The goal is to detail the nature of age changes in both brain anatomy, activity and cognitive processes, such as attention and memory and to investigate the effects of training the brain. What happens to your skills and brain in the event of intensive training in memory or attention tasks for months? If your memory improves, does your brain activity, or even brain anatomy, change? If individuals of different ages and health conditions train the brain equally much, are there similar or different effects? The project involves a combination o f basal, clinical and applied research. Three main questions will be investigated: 1) What is the nature of maturational and degenerative age changes? 2) Which patterns of age changes in neural activity signify successful compensation for neural age chang es and which signify inefficient processing? 3) By what mechanisms can we change cognitive performance at different ages and in clinical conditions? The applicant will study both a large population of healthy individuals (n = 350) across the ages 7-80 yrs , a clinical population with memory complaints (n = 50), and a rodent sample (n = 96). The project includes integration of morphometric and functional magnetic resonance (MR) imaging, including diffusion tensor imaging (DTI), histological markers, electro physiological event-related potentials (ERP) and neuropsychology. Research will be carried out at multiple levels, from molecular foundations to clinical signifiers and normal behavioral function, with the collaboration of national and international resea rch groups at the University of Oslo, Rikshospitalet-Radiumhospitalet, NTNU, Harvard and UCSD.