In an embodiment, the invention relates to neural prosthetic devices in which control signals are based on the cognitive activity of the prosthetic user. The control signals may be used to control an array of external devices, such as prosthetics, computer systems, and speech synthesizers. Data obtained from monkeys' movement intentions were recorded, decoded with a computer algorithm, and used to position cursors on a computer screen. Not only the intended goals, but also the value of the reward the animals expected to receive at the end of each trial, were decoded from the recordings. The results indicate that brain activity related to cognitive variables can be a viable source of signals for the control of a cognitive-based neural prosthetic.