Rehabilitation in brain disorders. 1. Basic sciences. This learning module highlights the basic sciences of brain disorders and their relevance to the rehabilitation process. It is part of the chapter on rehabilitation in brain disorders for the Self-Directed Medical Knowledge Program Study Guide for practitioners and trainees in physical medicine and rehabilitation. The chapter is composed of four articles, and each builds on principles established in the others. This article contains essential information on the hierarchy and integration of cerebral neural processes, functional anatomy, and neurochemistry. It also highlights newer advances in brain plasticity and response to injury, at a cellular level and with reference to acute and secondary processes, which will likely be at the forefront of medical management and functional "damage control" in the near future. The learner is directed to articles 2, 3, and 4 in this chapter for supporting information. 