While living in Boston, which has a fine metro system, there were times that I would exit from underground at the wrong location, thereby expecting a particular visual scene only to be momentarily confused that the expected scene did not correspond to my memorized scene. I am sure those of you who have lived in Boston or other cities with sub-ground metro lines have experienced this disconcertion (an experience that would be absent in patient HM, who had damage of the hippocampus, Corkin 2002). It is now accepted that all memories are stored in the neocortex within the context at the time of memorization/learning (Lu and Golomb 2023; also see Lamme 1995; Lamme and Roelfsema 2000; Zipser et al. 1996), and this includes the learning of language (memorizing lists of words with no linkage to usable language, i.e., context, will prevent against mastering a language). This supposition fits well with the view of Gestalt Psychology that all sensory information is stored as a whole, even though the whole can be reduced to its component parts (Kohler 1929).
Dotson and Yartsev (2021) have provided an understanding of how the brain stores information with context. To this end, they studied hippocampal place cells as fruit bats travelled at high speed through space, illustrating that the hippocampus, which consolidates and retrieves memories (Corkin 2002; Squire and Knowlton 2000; Squire et al. 2001; Wilson and McNaughton 1994), creates a linkage between the past, the present, and the future, namely, it establishes a context over time and space during learning. Some 27% of hippocampal neurons (81/304 neurons) encoded zero lag between the spatial position of a bat and the spike firing, and 46% of hippocampal neurons (140/304 neurons) encoded non-zero lag between the spatial position of a bat and the spike firing (Dotson and Yartsev 2021). More of the latter neurons encoded the future position over the past position. For the experiment, time was measured in increments of 0.1 seconds over a period of 2 seconds, with zero lag fixed at 1 second. Similar results to the forgoing have been reported for the hippocampus of other animals (e.g., Johnson and Redish 2007; O’Keef and Recce 1993; Kay et al. 2020).
Since the neural channels of the hippocampus are parallel—namely, independent, Knight (1964)—the consolidation process (representing the present and surmised future) and the retrieval process (representing the past) are encoded simultaneously as animals learn (Dotson and Yartsev 2021; also see Snyder, Yartsev et al. 2024). This should occur irrespective of the time scale: e.g., the neural effects of training on a task from previous days need to be retrieved and integrated with current learning that also involves making projections into the future. All this contributes to the storage of declarative information in the neocortex by context and by simultaneous updates of the executable code at the level of the cerebellum (Tehovnik, Hasanbegović, Chen 2024).