Understanding the workings of brain and nervous system; the cognitive processes they run has fascinated humanity for centuries. In an attempt to answer these questions, this paper presents a novel framework called ‘Neuronal State Theory’ rooted in the notion that a neuron has different neuronal states resulting from the concentrations of ionic species inside neurons. It is shown how all cognitive processes result from neuronal state theory. Furthermore, it is also shown all cognitive research fields (attention, memories, learning, imagination, sleep and dreams) emerge and are different aspects of the same presented framework.