As time passes after learning, connections between the hippocampus and neocortex gradually change. The exact time course of these changes is not well established and competing theories of memory consolidation debate if the role of the hippocampus in memory retrieval changes with the age of the memory. Functional magnetic resonance imaging (fMRI) can measure changes in retrieval-related brain function associated with the age of the memory to characterize the roles of the hippocampus and neocortex in memory consolidation. This dissertation aims to identify common functional brain networks associated with long-term memory consolidation by examining how these networks change with the age of the memory. Three fMRI studies in healthy adults were conducted to examine changes in retrieval-related brain function associated with different memory ages and types of memoranda. Each study measured whole-brain changes in retrieval-related brain activity, hippocampal functional connectivity, and ventromedial prefrontal cortex connectivity. In Chapter 1, I examine changes in brain function during retrieval of natural scenes learned 1 month to 1 hour prior to test. I demonstrate changes consistent with systems consolidation theory can be detected across short time periods. In Chapter 2, I examine changes in brain function during retrieval of three-word sentences learned 1 month to 1 hour prior to test. I similarly demonstrate changes consistent with systems consolidation theory can be detected across short time periods. In Chapter 3, I examine changes in brain function during retrieval of news events learned 1 year to 30 years prior to test. I demonstrate changes both consistent and inconsistent with memory consolidation theories are observed across long time periods. In the discussion, I compare commonalities between the brain networks identified in Chapters 1 and 2 which similarly change across short time periods but for different types of memoranda. I also compare the commonalities between the brain networks identified in Chapters 2 and 3 which change across both short and long time periods for similar memoranda. In sum, common changes in the functional roles of the hippocampus and neocortex consistent with memory consolidation can be detected across different types of memoranda and memory ages.