The purpose of this core is to develop, implement, and maintain the MRI instrumentation needed to carry out the proposed imaging experiments. There are three primary aspects to this Core: * Development and application of goal-based data acquisition software in close collaboration with the Goal-Based Model Acquisition and Rendering Project and the Computations and Algorithms Core * MRI probe design and construction * Routine maintenance and trouble shooting This Core will employ a Bruker AMX5OO NMR spectrometer with micro-imaging accessory that is already installed in the Biological Imaging Center of the Beckman Institute at Caltech. This instrument is controlled by a UNIX based workstation which is accessible over our local campus network. The In Vivo Atlases Of Brain Development Project and Elucidating Neuronal Connectivity With Novel Mri Agents Project will employ the instrumentation in this Core to obtain the required MR images. The Goal-Directed Model Acquisition And Rendering Project will use the AMX5OO as a test bed to implement and test the software being developed.