Working memory (WM) refers to a set of processes that makes task-relevant information accessible to higher-level cognitive processes. Recent work suggests WM is supported by a variety of information gating, updating, and removal processes, which ensure only task-relevant information occupies WM. Current neurocomputational theory suggests WM gating is accomplished via 'go/no-go' signalling in basal ganglia-thalamus-prefrontal cortex pathways, but is less clear about other subprocesses and brain structures known to play a role in WM. We review recent efforts to identify the neural basis of WM subprocesses using the recently developed reference-back task as a benchmark measure of WM subprocesses. Targets for future research using the methods of model-based cognitive neuroscience and novel extensions to the reference-back task are suggested.