1. A cloud-based computing system for taskless mapping of brain activity of an individual subject, the cloud-based computing system located remotely from a sensing system, the cloud-based computing system comprising a processor programmed to: select a plurality of time-series measurements of the brain activity obtained from the individual subject during a resting state, each selected time-series measurement corresponding to one location within a brain of the individual subject; for each selected time-series measurement, assemble a correlation map comprising a plurality of elements, each element comprising a correlation between the selected time-series measurement and another time series measurement from the plurality of time-series measurements; classify the resting state brain activity corresponding to each correlation map as at least one of a plurality of resting state networks by transforming each correlation map using a predetermined supervised classifier configured to transform a weighted sum of the elements of each correlation map to at least one output value, each output value indicating a membership of each correlation map within each corresponding resting state network of a plurality of resting state networks; and produce at least one map of resting state network membership by combining the at least one output value associated with the selected time-series measurements; wherein the predetermined supervised classifier is calibrated beforehand using a plurality of calibration time-series measurements corresponding to previously defined resting state networks obtained from a plurality of calibration subjects.