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Todd A. Girard

7 papers in the library · 182 citations · publishing 2006-2013

Papers

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The seahorse, the almond, and the night-mare: elaborative encoding during sleep-paralysis hallucinations?

Behavioral and Brain Sciences December 2013 Todd A. Girard

Llewellyn's proposal that rapid eye movement (REM) dreaming reflects elaborative encoding mediated by the hippocampus ("seahorse") offers an interesting perspective for understanding hallucinations accompanying sleep paralysis (SP; "night-mare"). SP arises from anomalous intrusion of REM processes into waking consciousness, including threat-detection systems mediated by the amygdala ("almond")....

Anomalous bodily-self experiences among recreational ketamine users.

Cognitive Neuropsychiatry 2012 Leanne K. Wilkins, Todd A. Girard, J Allan Cheyne

Out-of-body experiences present a unique paradigm to investigate cognitive and neural mechanisms of bodily-self processes and their disorders. Previous work on out-of-body experiences associated with sleep paralysis supported a model in which illusory movement experiences reflect disrupted bodily-self integration generating anomalous vestibular and motor sensations. Further disintegration and...

Ketamine as a primary predictor of out-of-body experiences associated with multiple substance use

Consciousness and Cognition February 16, 2011 Leanne K. Wilkins, Todd A. Girard, J. Allan Cheyne 57 citations

Investigation of "out-of-body experiences" (OBEs) has implications for understanding both normal bodily-self integration and its vulnerabilities. Beyond reported associations between OBEs and specific brain regions, however, there have been few investigations of neurochemical systems relevant to OBEs. Ketamine, a drug used recreationally to achieve dissociative experiences, provides a...

DOI: 10.1016/j.concog.2011.01.005 (opens in new tab) Ketamine Neurochemical Dissociative Neuropsychology +2

The body unbound: Vestibular–motor hallucinations and out-of-body experiences

Cortex June 6, 2008 J. Allan Cheyne, Todd A. Girard 125 citations

Among the varied hallucinations associated with sleep paralysis (SP), out-of-body experiences (OBEs) and vestibular-motor (V-M) sensations represent a distinct factor. Recent studies of direct stimulation of vestibular cortex report a virtually identical set of bodily-self hallucinations. Both programs of research agree on numerous details of OBEs and V-M experiences and suggest similar...

DOI: 10.1016/j.cortex.2007.05.002 (opens in new tab) Vestibular system Audiology Cognitive psychology

Mental representation of space: insights from an oblique distribution of hallucinations.

Neuropsychologia March 25, 2007 Todd A. Girard, Désirée L M A Martius, J Allan Cheyne

Three-dimensional spatial distributions of hypnagogic and hypnopompic hallucinations associated with sleep paralysis were used to investigate the internal representation of space. Left-right asymmetries in human preferences and abilities are well established. Parallel effects are also observed as lower-upper asymmetries. These parallels could reflect common underlying mechanisms or additive...

Paranoid delusions and threatening hallucinations: a prospective study of sleep paralysis experiences.

Consciousness and Cognition March 6, 2007 J Allan Cheyne, Todd A. Girard

Previously we reported a three-factor structure for hallucinations accompanying sleep paralysis (SP). These earlier analyses were, however, based on retrospective accounts. In a prospective study, 383 individuals reported individual episodes online providing further evidence for the three-factor structure as well as clearer conceptually meaningful relations among factors than retrospective...

DOI: 10.1016/j.concog.2007.01.002 (opens in new tab) Humans Hallucinations Sleep paralysis Health surveys +11

Timing of spontaneous sleep‐paralysis episodes

Journal of Sleep Research June 1, 2006 Todd A. Girard, J. Allan Cheyne

SummaryThe objective of this prospective naturalistic field study was to determine the distribution of naturally occurring sleep‐paralysis (SP) episodes over the course of nocturnal sleep and their relation to bedtimes. Regular SP experiencers (N = 348) who had previously filled out a screening assessment for SP as well as a general sleep survey were recruited. Participants reported, online...