scholarly journals Space, Time and Episodic Memory: the Hippocampus is all over the Cognitive Map

2017 ◽  
Author(s):  
Arne D. Ekstrom ◽  
Charan Ranganath

AbstractIn recent years, the field has reached an impasse between models suggesting that the hippocampus is fundamentally involved in spatial processing and models suggesting that the hippocampus automatically encodes all dimensions of experience in the service of memory. Here, we consider key conceptual issues that have impeded progress in our understanding of hippocampal function, and we review findings that establish the scope and limits of hippocampal involvement in navigation and memory. We argue that space and time serve as a primary scaffold to break up experiences into specific contexts, and to organize multimodal input that is to be associated within a context. However, the hippocampus is clearly capable of incorporating additional dimensions into the scaffold if they are determined to be relevant in the event-defined context. Conceiving of the hippocampal representation as constrained by immediate task demands—yet preferring axes that involve space and time—helps to reconcile an otherwise disparate set of findings on the core function of the hippocampus.

2019 ◽  
Author(s):  
Marilina Mastrogiuseppe ◽  
Natasha Bertelsen ◽  
Maria Francesca Bedeschi ◽  
Sang Ah Lee

AbstractRecent theories of episodic memory propose that the hippocampus provides the spatiotemporal framework for episodic memories. If this is true, does the development of episodic memory depend on the binding of space and time? And does this rely, at least partly, on normal hippocampal function? We investigated the development of episodic memory in children 2–8 years of age (Study 1) and its impairment in Williams Syndrome (Study 2) by implementing a nonverbal object-placement task that dissociates the what, where, and when components of episodic memory. Our results indicate that the binding of space and time in memory emerges first in development around the age of 3 and is impaired in Williams Syndrome. Space-time binding both preceded and predicted success in full episodic memory (what+where+when), and associating objects to spatial location seemed to mediate this developmental process. Importantly, these effects were not explained by improvements in object or location memory.


Hippocampus ◽  
2017 ◽  
Vol 28 (9) ◽  
pp. 680-687 ◽  
Author(s):  
Arne D. Ekstrom ◽  
Charan Ranganath

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marilina Mastrogiuseppe ◽  
Natasha Bertelsen ◽  
Maria Francesca Bedeschi ◽  
Sang Ah Lee

AbstractRecent theories of episodic memory (EM) posit that the hippocampus provides a spatiotemporal framework necessary for representing events. If such theories hold true, then does the development of EM in children depend on the ability to first bind spatial and temporal information? And does this ability rely, at least in part, on normal hippocampal function? We investigated the development of EM in children 2–8 years of age (Study 1) and its impairment in Williams Syndrome, a genetic neurodevelopmental disorder characterized by visuospatial deficits and irregular hippocampal function, (Study 2) by implementing a nonverbal object-placement task that dissociates the what, where, and when components of EM. Consistent with the spatiotemporal-framework view of hippocampal EM, our results indicate that the binding of where and when in memory emerges earliest in development, around the age of 3, and is specifically impaired in WS. Space-time binding both preceded and was critical to full EM (what + where + when), and the successful association of objects to spatial locations seemed to mediate this developmental process.


GEOgraphia ◽  
2009 ◽  
Vol 2 (3) ◽  
pp. 51
Author(s):  
Gilvan Luiz Hansen

Resumo Este artigo é uma discussão introdutória acerca da importância das concepções de espaço e tempo na modernidade. O objetivo deste texto é enfatizar os aspectos teóricos e práticos dos conceitos de espaço e tempo, mediante a apresentação de três perspectivas de interpretação desta questão na filosofia desenvolvida na modernidade. Palavras-chave: Modernidade, Espaço, Tempo, Filosofia Moderna, J. Habermas.Abstract This article is an introductory debate about the importance of space and time conceptions in modernity. The objective from this text is emphasize the theoretical and practical aspects of space and time concepts, by presentation of three interpretation perspectives of this question in the philosophy developed in modernity. Keywords: Modernity, Space, Time, Modern Philosophy, J. Habermas.


2010 ◽  
Vol 22 (1) ◽  
pp. 181-195 ◽  
Author(s):  
Anthony Cordingley

This essay argues for the presence of Aristotelian ideas of cosmic order, syllogism, space and time in Beckett's . It accounts for how such ideas impact upon the novel's 'I' as he attempts to offer a philosophical 'solution' to his predicament in an underworld divorced from the revolving heavens. Beckett's study of formal logic as a student at Trinity College, Dublin and his private study of philosophy in 1932 is examined in this light; particularly his “Philosophy Notes,” along with some possible further sources for his knowledge. The essay then reveals a creative transformation of Aristotelian ideas in which led to formal innovations, such as the continuous present of its narrative.


Genetics ◽  
1993 ◽  
Vol 133 (3) ◽  
pp. 711-727
Author(s):  
B K Epperson

Abstract The geographic distribution of genetic variation is an important theoretical and experimental component of population genetics. Previous characterizations of genetic structure of populations have used measures of spatial variance and spatial correlations. Yet a full understanding of the causes and consequences of spatial structure requires complete characterization of the underlying space-time system. This paper examines important interactions between processes and spatial structure in systems of subpopulations with migration and drift, by analyzing correlations of gene frequencies over space and time. We develop methods for studying important features of the complete set of space-time correlations of gene frequencies for the first time in population genetics. These methods also provide a new alternative for studying the purely spatial correlations and the variance, for models with general spatial dimensionalities and migration patterns. These results are obtained by employing theorems, previously unused in population genetics, for space-time autoregressive (STAR) stochastic spatial time series. We include results on systems with subpopulation interactions that have time delay lags (temporal orders) greater than one. We use the space-time correlation structure to develop novel estimators for migration rates that are based on space-time data (samples collected over space and time) rather than on purely spatial data, for real systems. We examine the space-time and spatial correlations for some specific stepping stone migration models. One focus is on the effects of anisotropic migration rates. Partial space-time correlation coefficients can be used for identifying migration patterns. Using STAR models, the spatial, space-time, and partial space-time correlations together provide a framework with an unprecedented level of detail for characterizing, predicting and contrasting space-time theoretical distributions of gene frequencies, and for identifying features such as the pattern of migration and estimating migration rates in experimental studies of genetic variation over space and time.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nitipong Pichetpan ◽  
Mark W. Post

Abstract This article provides a comprehensive analysis of the little-known “bare classifier phrase” construction in Modern Standard Thai. It describes the syntax, semantics and discourse functions of Thai bare classifier phrases, and further proposes a diachronic account of their origin in reduction of post-posed numeral ‘one’. Following this synchronic and diachronic description, this article attempts to locate Thai within a working typology of bare classifier constructions in mainland Asian languages, and further argues for the importance of bare classifier constructions to the theory of classifiers more generally. Following Bisang (1999) and others, it argues that bare classifier constructions reveal the core function of classifiers in Asian languages to be individuation – a referential function. It therefore cautions against some recent proposals to merge classifiers and gender markers within a single categorical space defined on the semantic basis of nominal classification, and in favour of continuing to treat classifiers as a discrete linguistic category – in mainland Asian languages, at least.


Author(s):  
Karen Nicholson

Local sites and practices of information work become embroiled in the larger imperatives and logics of the global knowledge economy through social, technological, and spatial networks. Drawing on human geography’s central claim that space and time are dialectically produced through social practices, in this essay I use human/critical geography as a framework to situate the processes and practices—the space and time—of information literacy within the broader social, political, and economic environments of the global knowledge economy.  As skills training for the knowledge economy, information literacy lies at the intersection of the spatial and temporal spheres of higher education as the locus of human capital production. Information literacy emerges as a priority for academic librarians in the 1980s in the context of neoliberal reforms to higher education: a necessary skill in the burgeoning “information economy,” it legitimates the role of librarians as teachers. As a strategic priority, information literacy serves to demonstrate the library’s value within the university’s globalizing agenda. While there has been a renewed interest in space/time within the humanities and social sciences since the 1980s, LIS has not taken up this “spatial turn” with the same enthusiasm—or the same degree of criticality—as other social science disciplines. This article attempts to address that gap and offers new insights into the ways that the spatial and temporal registers of the global knowledge economy and the neoliberal university produce and regulate the practice of information literacy in the academic library. Pre-print first published online 12/09/2018


2020 ◽  
Vol 35 (05) ◽  
pp. 2050024
Author(s):  
Reinoud Jan slagter ◽  
Christopher Levi Duston

We investigate the space–time of a spinning cosmic string in conformal invariant gravity, where the interior consists of a gauged scalar field. We find exact solutions of the exterior of a stationary spinning cosmic string, where we write the metric as [Formula: see text], with [Formula: see text] a dilaton field which contains all the scale dependences. The “unphysical” metric [Formula: see text] is related to the [Formula: see text]-dimensional Kerr space–time. The equation for the angular momentum [Formula: see text] decouples, for the vacuum situation as well as for global strings, from the other field equations and delivers a kind of spin-mass relation. For the most realistic solution, [Formula: see text] falls off as [Formula: see text] and [Formula: see text] close to the core. The space–time is Ricci flat. The formation of closed timelike curves can be pushed to space infinity for suitable values of the parameters and the violation of the weak energy condition can be avoided. For the interior, a numerical solution is found. This solution can easily be matched at the boundary on the exterior exact solution by special choice of the parameters of the string. This example shows the power of conformal invariance to bridge the gap between general relativity and quantum field theory.


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