Lynn Nadel. The hippocampal formation and action at a distance. Proceedings of the National Academy of Sciences Dec 2021, 118 (51) e2119670118; DOI: 10.1073/pnas.2119670118

“Why is it that the same neural system is so intimately involved in aspects of space and time and memory?”

“We suggested that highly nonlinear recurrent circuitries lay at the heart of this system, carrying out the pattern formation critical to its role in space, time and memory.”

“How the hippocampal formation carries out its role in such things as memory recall,retrieval, reconsolidation, and updating.”

Significance
“This article proposes an overarching hypothesis about the function of the hippocampal formation, namely, that it enables organisms to bridge significant spatial and temporal gaps in experience and is thereby deeply involved in aspects of spatial cognition, event segmentation, and memory. This brain system enables organisms to go beyond the here and now, utilizing prior experience to plan current and future behavior.”

Abstract
“The question of why our conceptions of space and time are intertwined with memory in the hippocampal formation is at the forefront of much current theorizing about this brain system. In this article I argue that animals bridge spatial and temporal gaps through the creation of internal models that allow them to act on the basis of things that exist in a distant place and/or existed at a different time. The hippocampal formation plays a critical role in these processes by stitching together spatiotemporally disparate entities and events. It does this by 1) constructing cognitive maps that represent extended spatial contexts, incorporating and linking aspects of an environment that may never have been experienced together; 2) creating neural trajectories that link the parts of an event, whether they occur in close temporal proximity or not, enabling the construction of event representations even when elements of that event were experienced at quite different times; and 3) using these maps and trajectories to simulate possible futures. As a function of these hippocampally driven processes, our subjective sense of both space and time are interwoven constructions of the mind, much as the philosopher Immanuel Kant postulated.”

Lynn Nadel. The hippocampal formation and action at a distance. Proceedings of the National Academy of Sciences Dec 2021, 118 (51) e2119670118; DOI: 10.1073/pnas.2119670118