Abstract
Hippocampal cognitive map—a neuronal representation of the spatial environment—is widely discussed in the computational neuroscience literature for decades. However, more recent studies point out that hippocampus plays a major role in producing yet another cognitive framework—the memory space—that incorporates not only spatial, but also non-spatial memories. Unlike the cognitive maps, the memory spaces, broadly understood as “networks of interconnections among the representations of events,” have not yet been studied from a theoretical perspective. Here we propose a mathematical approach that allows modeling memory spaces constructively, as epiphenomena of neuronal spiking activity and thus to interlink several important notions of cognitive neurophysiology. First, we suggest that memory spaces have a topological nature—a hypothesis that allows treating both spatial and non-spatial aspects of hippocampal function on equal footing. We then model the hippocampal memory spaces in different environments and demonstrate that the resulting constructions naturally incorporate the corresponding cognitive maps and provide a wider context for interpreting spatial information. Lastly, we propose a formal description of the memory consolidation process that connects memory spaces to the Morris' cognitive schemas-heuristic representations of the acquired memories, used to explain the dynamics of learning and memory consolidation in a given environment. The proposed approach allows evaluating these constructs as the most compact representations of the memory space's structure.
Highlights
In the neurophysiological literature, the functions of mammalian hippocampus are usually discussed from the following two main perspectives
One group of studies addresses the role of the hippocampus in representing the ambient space in a cognitive map (Tolman, 1948; Moser et al, 2008), and the other focuses on its role in processing non-spatial memories, notably the episodic memory frameworks (Eichenbaum, 2004; Dere et al, 2006; Hassabis et al, 2007; Crystal, 2009)
The discrete memories that comprise a memory space may be triggered by constellations of cues and/or actions, that drive the activity of a particular population of cell assemblies (Buzsaki et al, 2014)
Summary
The functions of mammalian hippocampus are usually discussed from the following two main perspectives. One group of studies addresses the role of the hippocampus in representing the ambient space in a cognitive map (Tolman, 1948; Moser et al, 2008), and the other focuses on its role in processing non-spatial memories, notably the episodic memory frameworks (Eichenbaum, 2004; Dere et al, 2006; Hassabis et al, 2007; Crystal, 2009) Active studies of the former began with the discovery of the “place cells”—hippocampal neurons that fire action potentials in discrete regions of the environment—their respective “place fields.”. The concept of memory space generalizes the notion of cognitive map: the latter unifies spatial memories and forms a substructure or a subspace embedded into a larger memory space
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have