Cognitive neuroscience maps mental states to brain states. That is, we observe behavior (such as wiggling one's toes, or reacting to pain) or mental states (such as depression, memory retrieval, mathematical processing, thinking about a chair, etc) while scanning the brain. read more
Since all major universities have programs in cognitive neuroscience, and there are many people like myself paid to develop the computational cognitive modelling software, I think it's pretty safe to declare it legitimate. I suggest investing some time with an online book: Computational Cognitive Neuroscience Wiki. read more
Cognitive neuroscience is a branch of both neuroscience and psychology, overlapping with disciplines such as behavioral neuroscience, cognitive psychology, physiological psychology and affective neuroscience. read more