This is very interesting:
Brain Cells ‘Geotag’ Memories To Cache What Happened — And Where
As we form so-called episodic memories, the brain appears to be using special cells in the hippocampus to "geotag" each event, in Science. The process is similar to what some digital cameras do when they tag each picture with information about where the image was taken.
In many species, spatial navigation is supported by a network of place cells that exhibit increased firing whenever an animal is in a certain region of an environment. Does this neural representation of location form part of the spatiotemporal context into which episodic memories are encoded? We recorded medial temporal lobe neuronal activity as epilepsy patients performed a hybrid spatial and episodic memory task. We identified place-responsive cells active during virtual navigation and then asked whether the same cells activated during the subsequent recall of navigation-related memories without actual navigation. Place-responsive cell activity was reinstated during episodic memory retrieval. Neuronal firing during the retrieval of each memory was similar to the activity that represented the locations in the environment where the memory was initially encoded.