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    LSD alters eyes-closed functional connectivity within the early visual cortex in a retinotopic fashion

    Roseman, L. and Sereno, Martin I. and Leech, R. and Kaelen, M. and Orban, C. and McGonigle, J. and Feilding, A. and Nutt, D.J. and Carhart-Harris, R.L. (2016) LSD alters eyes-closed functional connectivity within the early visual cortex in a retinotopic fashion. Human Brain Mapping 37 (8), pp. 3031-3040. ISSN 1065-9471.

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    Abstract

    The question of how spatially organized activity in the visual cortex behaves during eyes-closed, lysergic acid diethylamide (LSD)-induced “psychedelic imagery” (e.g., visions of geometric patterns and more complex phenomena) has never been empirically addressed, although it has been proposed that under psychedelics, with eyes-closed, the brain may function “as if” there is visual input when there is none. In this work, resting-state functional connectivity (RSFC) data was analyzed from 10 healthy subjects under the influence of LSD and, separately, placebo. It was suspected that eyes-closed psychedelic imagery might involve transient local retinotopic activation, of the sort typically associated with visual stimulation. To test this, it was hypothesized that, under LSD, patches of the visual cortex with congruent retinotopic representations would show greater RSFC than incongruent patches. Using a retinotopic localizer performed during a nondrug baseline condition, nonadjacent patches of V1 and V3 that represent the vertical or the horizontal meridians of the visual field were identified. Subsequently, RSFC between V1 and V3 was measured with respect to these a priori identified patches. Consistent with our prior hypothesis, the difference between RSFC of patches with congruent retinotopic specificity (horizontal–horizontal and vertical–vertical) and those with incongruent specificity (horizontal–vertical and vertical–horizontal) increased significantly under LSD relative to placebo, suggesting that activity within the visual cortex becomes more dependent on its intrinsic retinotopic organization in the drug condition. This result may indicate that under LSD, with eyes-closed, the early visual system behaves as if it were seeing spatially localized visual inputs.

    Metadata

    Item Type: Article
    Additional Information: This is the peer reviewed version of the article, which has been published in final form at the link above. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
    Keyword(s) / Subject(s): psychedelics, serotonin 5-HT2 receptor agonists, LSD, visual cortex, fMRI, imagery, hallucinations
    School: Birkbeck Schools and Departments > School of Science > Psychological Sciences
    Depositing User: Administrator
    Date Deposited: 17 May 2016 16:22
    Last Modified: 27 Jul 2019 16:52
    URI: http://eprints.bbk.ac.uk/id/eprint/15213

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