Rodriguez-Esteban, RaulCherniak, ChristopherPrinciples of connection minimization in the nervous system apply not only to complete neural systems but also to smaller subsystems such as rat olfactory cortex and rat amygdala. These subsystems have a three-dimensional organization, rather than previously-studied two-dimensional and one-dimensional schemes. Nonetheless, wire-cost savings show optimality at similar levels, suggesting neural optimization principles are widespread, followed at multiple scales of the nervous system.en-USTechnical Report