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Directed coupling in local field potentials of macaque V4 during visual short-term memory revealed by multivariate autoregressive models

  • Hoerzer, Gregor M. Institute for Theoretical Computer Science, Graz University of Technology, Graz, Austria
  • Liebe, Stefanie Department of Physiology of Cognitive Processes, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
  • Schloegl, Alois Institute for Human-Computer Interfaces, Graz University of Technology, Graz, Austria
  • Logothetis, Nikos K. Department of Physiology of Cognitive Processes, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
  • Rainer, Gregor Department of Physiology of Cognitive Processes, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany - Department of Medicine/Physiology, University of Fribourg, Switzerland
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    26.05.2010
Published in:
  • Frontiers in Computational Neuroscience. - 2010, vol. 4, p. 14
multivariate autoregressive model
local field potential
partial directed coherence
visual short term memory
macaque monkey
theta frequency range
V4
multi-channel recordings
English Processing and storage of sensory information is based on the interaction between different neural populations rather than the isolated activity of single neurons. In order to characterize the dynamic interaction and transient cooperation of sub-circuits within a neural network, multivariate autoregressive (MVAR) models have proven to be an important analysis tool. In this study, we apply directed functional coupling based on MVAR models and describe the temporal and spatial changes of functional coupling between simultaneously recorded local field potentials in extrastriate area V4 during visual memory. Specifically, we compare the strength and directional relations of coupling based on generalized partial directed coherence (GPDC) measures while two rhesus monkeys perform a visual short-term memory task. In both monkeys we find increases in theta power during the memory period that are accompanied by changes in directed coupling. These interactions are most prominent in the low frequency range encompassing the theta band (3–12 Hz) and, more importantly, are asymmetric between pairs of recording sites. Furthermore, we find that the degree of interaction decreases as a function of distance between electrode positions, suggesting that these interactions are a predominantly local phenomenon. Taken together, our results show that directed coupling measures based on MVAR models are able to provide important insights into the spatial and temporal formation of local functionally coupled ensembles during visual memory in V4. Moreover, our findings suggest that visual memory is accompanied not only by a temporary increase of oscillatory activity in the theta band, but by a direction-dependent change in theta coupling, which ultimately represents a change in functional connectivity within the neural circuit.
Faculty
Faculté des sciences et de médecine
Department
Département de Médecine
Language
  • English
Classification
Biological sciences
License
License undefined
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https://folia.unifr.ch/unifr/documents/301886
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