Is prefrontal cortex necessary for the storage and acquisition of relational concepts?

The ability to make analogies requires building higher order relations and so keeping track of multiple independently varying dimensions of the concepts being compared. Frontal cortex may be well suited to support this type of function, as Speed's review makes clear. However, Speed goes further in arguing that PFC neurons necessarily support the storage and acquisition of relational concepts. This claim is evaluated in the context of broader perspectives on storage and acquisition of semantic knowledge.