Our findings also bolster an important perspective in the memory literature: other brain hubs, outside of the MTL, contribute significantly to episodic memory. Past lesion work supports the idea that brain damage outside of the hippocampus, including prefrontal cortex15 and parietal cortex10, impairs episodic memory, reinforcing the idea that this important function involves brain hubs across multiple lobes. Thus, while past work has also suggested the importance of extra-hippocampal brain areas to memory (for reviews, see1642), our results suggest a reason why: prefrontal cortex, precuneus, and visual cortex are densely connected during successful memory retrieval. Our results further suggest one reason why hippocampal damage, in particular, may be devastating to episodic memory. While prefrontal cortex showed greater connectivity during temporal order compared to spatial layout retrieval and parietal cortex showed greater connectivity during spatial layout retrieval compared to temporal order retrieval, only the hippocampus (and other parts of the MTL) acted as a hub during both spatial and temporal order processing. The importance of the hippocampus to spatiotemporal memory is consistent with numerous studies using human neuroimaging643, intracranial EEG recordings14,
