It is argued that in poorly understood domains functional imaging and neuropsychology findings on cognitive processes can be related only through functional models of normal cognition. The psychological concept of "resource" can, however, be simply extrapolated to functional imaging. It is then argued that double dissociations can have analogous inferential power for extrapolation to models of normal cognition in functional imaging as in neuropsychology. The argument is illustrated by the example of the control processes involved in functional episodic memory imaging of experiments.