Infinite storage capacity of memory-like mechanisms in the hippocampus: a cryptographic perspective on animal’s caching and retrieval behaviors

The brain’s extraordinary abilities are often associated with its ability to learn and adapt. But memory and plasticity have their limitations, especially when faced with tasks such as retrieving thousands of food items such as in the case of scatter-hoarding animals. Here, we suggest a brain mechanism that works by utilizing cryptographic principles in lieu of plasticity. Rather than memorizing the locations of their caches, as previously suggested, we propose that cache-hoarding animals use a single cryptographic-like mechanism for both caching and retrieval. The mathematical model we developed functions similarly to hippocampal spatial cells, which respond to an animal’s positional attention. We know that the region that activates each spatial cell remains consistent across subsequent visits to the same area but not between areas. This remapping, combined with the uniqueness of cognitive maps, produces a persistent crypto-hash function for both food caching and retrieval. We show that our model is consistent with previous observations, such as animals’ ability to prioritize food items that are perishable or by their nutritional value. The model makes several measurable predictions regarding scattered hoarding and what factors can limit an animal’s retrieval success. Finally, while focusing here on scatter-hoarding, the mechanism we present might be utilized by the brain in other ways providing essentially infinite retention capacity for structured data.