Episodic memory is one of the most remarkable human cognitive faculties. While prototypes of episodic memory were shown to exist in non-human animals, mental time travel - imagining oneself at different past and future times - and episodic construction are believed to be uniquely human. These properties of human memory inspired countless studies over the last six decades, however, to date, it remains unknown why episodic memory is so well developed in humans compared with other animals. On the neural level, episodic memory critically depends on the hippocampal system that remained largely conserved during 200 million years of mammalian evolution, especially when compared to the phylogenetic variation in the size and functional specialization of the cerebral cortex. Inspired by the striking phylogenetic conservation of the hippocampal system, we have leveraged recent advances in the fields of human imaging (Reznik et al., 2024 Neuron; Reznik et al., 2023 Curr Bio) and animal anatomy to propose a comparative anatomical framework elucidating the evolutionary trajectory of human memory (Reznik et al., under revision). We focused on the anatomical connectivity of the hippocampal region, and tested the hypothesis that the cortical input to the hippocampal region systematically changed during mammalian evolution, potentially underpinning cross- species variability in hippocampus-dependent functions. To this end we examined anatomical connectivity data from six species representing branches of the mammalian evolutionary tree that diverged over more than 100 million years - the tenrec, rat, cat, marmoset, macaque, and human. Critically, we used data from all species for which connectivity of the hippocampal region is known. Our results point to a previously unknown structure in evolutionary changes of cortical input to the hippocampal regions: (1) unimodal cortical input to the hippocampal region was selectively and gradually eliminated, while transmodal cortical input was preserved; (2) input from primary sensory regions was eliminated prior to the elimination of input from non- primary sensory regions; (3) selective preservation of transmodal input to the hippocampal region underpins the evolutionary trajectory of the hippocampal-cortical circuitry into its current human form. While our findings suggest that hippocampus-related processing in different species operates on fundamentally different types of information, it is still unknown how these changes are reflected in cross-species differences in episodic encoding and recollection. In the proposed project, based on the abovementioned phylogenetic differences in anatomical connectivity of the hippocampal system, I’d like to formulate a novel theoretical account, which (1) explains the unique properties of human memory compared with the rest of the animal kingdom and (2) addresses phenomenological differences in episodic memory across species. To this end, I will combine existing behavioral data, evolutionary biology and computational modeling (e.g., Spens and Burges, 2024 Nat Hum Behav) to test anatomy-driven functional hypotheses addressing episodic memory in different species. The proposed project would aim to generate an opinion manuscript, which would serve as an important milestone for adopting an evolutionary perspective into the study of the hippocampal region and reshape how researchers interested in brain evolution and comparative neuroanatomy approach episodic memory.