1. A method for stimulating neurons of a brainstem or midbrain of a patient to provide sensations for the patient, the method comprising: generating a plurality of light signals that, when applied to a neuron of a person, directly stimulates a nerve action potential in the neuron; delivering the light signals to a plurality of neurons of the brainstem or midbrain of the patient; selectively controlling the plurality of light signals to directly optically stimulate the plurality of neurons in order to control nerve action potentials (NAPs) produced by the plurality of neurons; receiving sensed electromagnetic-radiation data indicative of a color; and processing the received electromagnetic-radiation data to obtain color information, wherein the delivering of light signals comprises delivering the light pulses to a vision portion of the brainstem or midbrain of the patient to provide a sensation of the color to the patient.