Neural prostheses receive considerable attention due to their potential to dramatically improve the quality of life of severely disabled patients. Cortically-controlled prostheses are able to translate neural activity from cerebral cortex into control signals for guiding computer cursors or prosthetic limbs. Non-invasive and invasive electrode techniques can be used to measure neural activity,with the latter promising considerably higher levels of performance and therefore functionality to patients. In this talk, I will review some of our recent experimental and computational work aimed at establishing a principled design methodology to increase electrode-based cortical prosthesis performance. Studies discussed include translating brief periods of “plan” activity into high information rate (6.5 bits/s) control signals, improving decode algorithms and optimizing visual target locations for further performance increases, and recording from freely behaving monkeys to characterize neuron stability. Taken together, these results should substantially increase the clinical viability of cortical prostheses.