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A Hierarchy of Time-Scales and the Brain

Kiebel, SJ; Daunizeau, J; Friston, KJ; (2008) A Hierarchy of Time-Scales and the Brain. PLOS COMPUT BIOL , 4 (11) , Article e1000209. 10.1371/journal.pcbi.1000209. Green open access

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Abstract

In this paper, we suggest that cortical anatomy recapitulates the temporal hierarchy that is inherent in the dynamics of environmental states. Many aspects of brain function can be understood in terms of a hierarchy of temporal scales at which representations of the environment evolve. The lowest level of this hierarchy corresponds to fast fluctuations associated with sensory processing, whereas the highest levels encode slow contextual changes in the environment, under which faster representations unfold. First, we describe a mathematical model that exploits the temporal structure of fast sensory input to track the slower trajectories of their underlying causes. This model of sensory encoding or perceptual inference establishes a proof of concept that slowly changing neuronal states can encode the paths or trajectories of faster sensory states. We then review empirical evidence that suggests that a temporal hierarchy is recapitulated in the macroscopic organization of the cortex. This anatomic-temporal hierarchy provides a comprehensive framework for understanding cortical function: the specific time-scale that engages a cortical area can be inferred by its location along a rostro-caudal gradient, which reflects the anatomical distance from primary sensory areas. This is most evident in the prefrontal cortex, where complex functions can be explained as operations on representations of the environment that change slowly. The framework provides predictions about, and principled constraints on, cortical structure-function relationships, which can be tested by manipulating the time-scales of sensory input.

Type: Article
Title: A Hierarchy of Time-Scales and the Brain
Open access status: An open access version is available from UCL Discovery
DOI: 10.1371/journal.pcbi.1000209
Publisher version: http://dx.doi.org/10.1371/journal.pcbi.1000209
Language: English
Additional information: © 2008 Kiebel et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. SJK and KJF are funded by the Wellcome Trust. JD is funded by a European Marie-Curie fellowship.
Keywords: CLASSICAL RECEPTIVE-FIELD, CORTICAL CONNECTIONS, PREFRONTAL CORTEX, SPEECH-PERCEPTION, FEEDBACK-CONTROL, AUDITORY-CORTEX, BEHAVIOR, COGNITION, DYNAMICS, SYSTEM
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Imaging Neuroscience
URI: https://discovery.ucl.ac.uk/id/eprint/112816
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