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Recognizing Sequences of Sequences

Kiebel, SJ; von Kriegstein, K; Daunizeau, J; Friston, KJ; (2009) Recognizing Sequences of Sequences. PLoS Computational Biology , 5 (8) , Article e1000464. 10.1371/journal.pcbi.1000464. Green open access

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Abstract

The brain's decoding of fast sensory streams is currently impossible to emulate, even approximately, with artificial agents. For example, robust speech recognition is relatively easy for humans but exceptionally difficult for artificial speech recognition systems. In this paper, we propose that recognition can be simplified with an internal model of how sensory input is generated, when formulated in a Bayesian framework. We show that a plausible candidate for an internal or generative model is a hierarchy of 'stable heteroclinic channels'. This model describes continuous dynamics in the environment as a hierarchy of sequences, where slower sequences cause faster sequences. Under this model, online recognition corresponds to the dynamic decoding of causal sequences, giving a representation of the environment with predictive power on several timescales. We illustrate the ensuing decoding or recognition scheme using synthetic sequences of syllables, where syllables are sequences of phonemes and phonemes are sequences of sound-wave modulations. By presenting anomalous stimuli, we find that the resulting recognition dynamics disclose inference at multiple time scales and are reminiscent of neuronal dynamics seen in the real brain.

Type: Article
Title: Recognizing Sequences of Sequences
Open access status: An open access version is available from UCL Discovery
DOI: 10.1371/journal.pcbi.1000464
Publisher version: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC271497...
Language: English
Additional information: © 2009 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.
Keywords: CONTINUOUS SPEECH RECOGNITION, SHORT-TERM-MEMORY, BAYESIAN-INFERENCE, WINNERLESS COMPETITION, TRANSIENT DYNAMICS, NEURONAL DYNAMICS, CORTICAL NETWORKS, AUDITORY-CORTEX, MODEL, PERCEPTION
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/118914
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