1. A computing device for use in a system for task-less mapping of brain activity of a subject, the computing device comprising a processor programmed to: select a plurality of measurements of brain activity that is representative of at least one parameter of a brain of the subject during a resting state; compare at least one data point from each of the plurality of measurements with a corresponding data point from a previously acquired data set from at least one other subject; produce at least one map for each of the plurality of measurements based on the comparison of the at least one resting state data point and the corresponding previously acquired data point; and categorize the brain activity in a plurality of networks in the brain based on the at least one map.