CortexNovember 3, 2018Elizabeth Milne, Stephanie Dunn, Chen Zhao et al.
It has been suggested that individual differences in cortical excitability leading to disruption of the timing and integration of sensory information processing may explain why some people have out of body experiences (OBE) in the absence of any known pathological or psychiatric condition. Here we recorded EEG from people who either had, or had not experienced an OBE in order to investigate the...
Out-of-body experiences (OBEs) are states during which people experience their centre of awareness as located outside of their physical body, along with the sensation of seeing the environment from an elevated viewpoint. OBE is encountered in epilepsy, migraine and depersonalization, and it is not an uncommon experience in the general population. Current neuroscientific models of bodily...
Interoceptive signals, such as the heartbeat, are processed in a network of brain regions including the insular cortex. Recent studies have shown that such signals modulate perceptual and cognitive processing, and that they impact visual awareness. For example, visual stimuli presented synchronously to the heartbeat take longer to enter visual awareness than the same stimuli presented...
One of the most challenging questions regarding the nature and neural basis of consciousness is the embodied dimension of the phenomenon, that is, feeling located within the body and viewing the world from that spatial perspective. Current theories in neurophysiology highlight the active role of multisensory and sensorimotor integration in supporting self-location and self-perspective, and...
Our experience of the body is not direct; rather, it is mediated by perceptual information, influenced by internal information, and recalibrated through stored implicit and explicit body representation (body memory). This paper presents an overview of the current investigations related to body memory by bringing together recent studies from neuropsychology, neuroscience, and evolutionary and...
In this report, we analyze the relationship between embodied cognition and current theories of the cerebellum, particularly the Dysmetria of Thought theory and the concept of the Universal Cerebellar Transform (UCT). First, we describe the UCT and the Dysmetria of Thought theories, highlight evidence supporting these hypotheses and discuss their mechanisms, functions and relevance. We then...
How can perceptual consciousness be indexed in humans? Recent work with ERPs suggests that P3b, a relatively late component, may be a neural correlate of consciousness (NCC). This proposal dovetails with currently prevailing cognitive theory regarding the nature of conscious versus unconscious processes, which holds that the latter are simple and very brief, whereas consciousness is ostensibly...
Involuntary movements occur in a variety of neuropsychiatric disorders and culturally influenced dissociative states (e.g., delusions of alien control and attributions of spirit possession). However, the underlying brain processes are poorly understood. We combined suggestion and fMRI in 15 highly hypnotically susceptible volunteers to investigate changes in brain activity accompanying...
After a hypnotic induction, medium and highly hypnotizable individuals often report spontaneous alterations in various dimensions of consciousness. Few studies investigating these experiences have controlled for the inherent demands of specific hypnotic suggestions and fewer still have considered their dynamic properties and neural correlates. We adopted a neurophenomenological approach to...
Cognitive scientists typically classify cognitive processes as either controlled or automatic. Whereas controlled processes are slow and effortful, automatic processes are fast and involuntary. Over the past decade, we have propelled a research trajectory investigating how top-down influence in the form of suggestion can allow individuals to modulate the automaticity of cognitive processes....
Individuals with no history of neurological or psychiatric illness can report hallucinatory Out-of-Body Experiences (OBEs) and display elevated scores on measures of temporal-lobe dysfunction (Braithwaite et al., 2011). However, all previous investigations of such biases in non-clinical populations are based on indirect questionnaire measures. Here we present the first empirical investigation...
Synaesthesia is a condition in which one property of a stimulus induces a conscious experience of an additional attribute. For example, in grapheme-colour synaesthesia, a visually presented grapheme results in synaesthetic experiences of colour. These experiences occur in approximately 4% of the population (Simner et al., 2006) and the authenticity of the condition is well established (Cohen...
Recent findings from studies of epileptic patients and schizotypes have suggested that disruptions in multi-sensory integration processes may underlie a predisposition to report out-of-body experiences (OBEs: Blanke et al., 2004; Mohr et al., 2006). It has been argued that these disruptions lead to a breakdown in own-body processing and embodiment. Here we present two studies which provide the...
CortexMay 18, 2009Jiongjiong Yang, Xuchu Weng, Yufeng Zang et al.
Recent neuroimaging studies have shown that several brain regions--namely, the posterior cingulate cortex (PCC), ventral medial prefrontal cortex (vmPFC), and the bilateral angular gyrus--are more active during resting states than during cognitive tasks (i.e., default mode network). Although there is evidence showing that the default mode network is associated with unconscious state, it is...
Self-processing has been related to the prefrontal cortex (PFC) and the temporo-parietal junction (TPJ) as well as to their connectivity. So far, out-of-body experiences (OBEs), impressive transient deviations of intact bodily self-integration, could be associated with the TPJ, but the mediation by the frontal lobe, and thus fronto-parietal connectivity, is yet unknown. Thus, we assessed...
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...
The visual content of out-of-body experiences (OBEs) has received little attention but a number of theories of OBEs include implicit predictions regarding the determinants of this phenomenological feature. Hypnagogic imagery and unusual sleep experiences, weak synaesthesia and preference for employing object and spatial visual imagic cognitive styles were psychometrically measured along with...
Cortex2008Jessica I Fleck, Deborah L Green, Jennifer L Stevenson et al.
Transliminality reflects individual differences in the threshold at which unconscious processes or external stimuli enter into consciousness. Individuals high in transliminality possess characteristics such as magical ideation, belief in the paranormal, and creative personality traits, and also report the occurrence of manic/mystic experiences. The goal of the present research was to determine...
Previous research has shown that people reporting contact with aliens, known as "experiencers", appear to have a different psychological profile compared to control participants. They show higher levels of dissociativity, absorption, paranormal belief and experience, and possibly fantasy proneness. They also appear to show greater susceptibility to false memories as assessed using the...
Ganzfeld, i.e., exposure to an unstructured, uniform stimulation field, elicits in most observers pseudo-hallucinatory percepts, and may even induce global functional state changes ('altered states of consciousness'). The present paper gives a comprehensive overview of the phenomenology of subjective experience in the ganzfeld and its electrophysiological correlates. Laboratory techniques for...
According to the dominant focus model, the differential activation of the thalamocortical network is a sufficient condition for the diversity of states of consciousness to occur, and coherent patterns of interactive forebrain activation peaks are sufficient to generate specific conscious figures against ground. These minimal assumptions are consonant with the known properties of unilateral...
Coloured hearing synaesthetes experience colours to heard words, as confirmed by reliability of self-report, psychophysical testing and functional neuroimaging data. Some also describe the 'alien colour effect' (ACE): in response to colour names, they experience colours different from those named. We have previously reported that the ACE slows colour naming in a Stroop task, reflecting...
CortexOctober 1, 2005Alexei V Samsonovich, Giorgio A Ascoli
Here we address the notion of the self as the subject of experience, in contrast with its other popular meanings of a state of self-awareness, a body image, or a narrative center. In this perspective, the main player is not consciousness per se (the famous "hard problem"), but its subject. We start by showing that the self as the subject of immediate self-awareness cannot be conceived as an...
Our paper addresses, as did a recent study by Greenwood et al. (1977), the question of differential right vs. left hemispheric involvement in REM-sleep dreaming. A male subject with extensive lesioning of the right hemisphere and consequent contralateral homonymous hemianopia was studied for 2 nights in a sleep laboratory where a dream report was collected following each of 6 awakenings from...
CortexSeptember 1, 1977P Greenwood, D H Wilson, M S Gazzaniga
This paper addresses the question of right hemisphere involvement in the visual components of dreaming. The rationale derives from an observed relation between reports of visual agnosia accompanied by dream cessation and the literature on right hemisphere specialization for visuo-spatial processes. All night sleep EEGs were recorded from subjects with partial or complete section of the corpus...