Cognitive Training is an OpenNeuro MRI dataset of 166 participants across two sessions designed to support research on cognitive training, decision-making, and brain activity. It contains structural and diffusion MRI data along with functional MRI from a resting-state scan, an intertemporal choice task, and a risky choice task. In the intertemporal choice task, participants chose between a larger delayed monetary reward and $20 immediately; in the risky choice task, they chose between a larger risky reward and $20 for certain, responding with their thumbs to accept or reject offers. The dataset can be used to study neural and behavioral mechanisms of valuation, risk, delay discounting, and cognitive training effects.