Intrainsular functional connectivity in human

Authors

  • Talal Almashaikhi,

    1. Translational and Integrative Group in Epilepsy Research (TIGER), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
    2. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
    3. Department of Clinical Physiology, Neurophysiology division, Sultan Qaboos University Hospital, Muscat, Oman
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  • Sylvain Rheims,

    1. Translational and Integrative Group in Epilepsy Research (TIGER), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
    2. Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France
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  • Karine Ostrowsky-Coste,

    1. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
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  • Alexandra Montavont,

    1. Translational and Integrative Group in Epilepsy Research (TIGER), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
    2. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
    3. Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France
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  • Julien Jung,

    1. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
    2. Dynamique Cérébrale et Cognition (DYCOG), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
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  • Julitta De Bellescize,

    1. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
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  • Alexis Arzimanoglou,

    1. Translational and Integrative Group in Epilepsy Research (TIGER), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
    2. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
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  • Pascal Keo Kosal,

    1. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
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  • Marc Guénot,

    1. Department of Functional Neurosurgery, Hospices Civils de Lyon, Lyon, France
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  • Olivier Bertrand,

    1. Dynamique Cérébrale et Cognition (DYCOG), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
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  • Philippe Ryvlin

    Corresponding author
    1. Translational and Integrative Group in Epilepsy Research (TIGER), Lyon's Neuroscience Research Centre, INSERM U1028, CNRS 5292, UCB Lyon 1, Lyon, France
    2. Pediatric Epilepsy Department, Hospices Civils de Lyon, Lyon, France
    3. Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Lyon, France
    • Correspondence to: Philippe Ryvlin, Department of Functional Neurology and Epileptology, Hospices Civils de Lyon, Unité 301, Hôpital Neurologique, 59 bd Pinel, Lyon, France. E-mail: ryvlin@cermep.fr.

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Abstract

Objectives

The anatomical organization of the insular cortex is characterized by its rich and heterogeneous cytoarchitecture and its wide network of connections. However, only limited knowledge is available regarding the intrainsular connections subserving the complex integrative role of the insular cortex. The aim of this study was to analyze the functional connectivity within- and across-insular subregions, at both gyral and functional levels.

Experimental design

We performed intracerebral electrical stimulation in 10 patients with refractory epilepsy investigated with depth electrodes, 38 of which were inserted in the insula. Bipolar electrical stimulation, consisting of two series of 20 pulses of 1-ms duration, 0.2-Hz frequency, and 1-mA intensity, was delivered at each insular contact. For each stimulated insular anatomical region, we calculated a rate of connectivity, reflecting the proportion of other insular contacts, showing significant evoked potentials.

Results

Statistically significant evoked potentials were recorded in 74% of tested connections, with an average latency of 26 ± 3 ms. All insular gyri were interconnected, except the anterior and posterior short gyri. Most connections were reciprocal, showing no clear anterior to posterior directionality. No connection was observed between the right and the left insula.

Conclusions

These findings point to specific features of human insula connectivity as compared to non-Human primates, and remain consistent with the complex integration role devoted to the human insula in many cognitive domains. Hum Brain Mapp 35:2779–2788, 2014. © 2013 Wiley Periodicals, Inc.

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