A well bore in a subterranean formation includes a signaling subsystem communicably coupled to injection tools installed in the well bore. Each injection tool controls a flow of fluid into an interval of the formation based on a state of the injection tool. Stresses in the subterranean formation are altered by creating fractures in the formation. Control signals are sent from the well bore surface through the signaling subsystem to the injection tools to modify the states of one or more of the injection tools. Fluid is injected into the stress-altered subterranean formation through the injection tools to create a fracture network in the subterranean formation. In some implementations, the state of each injection tool can be selectively and repeatedly manipulated based on signals transmitted from the well bore surface. In some implementations, stresses are modified and/or the fracture network is created along a substantial portion and/or the entire length of a horizontal well bore.