Ganzfeld-induced hallucinatory experience, its phenomenology and cerebral electrophysiology

@article{Wackermann2008GanzfeldinducedHE,
  title={Ganzfeld-induced hallucinatory experience, its phenomenology and cerebral electrophysiology},
  author={Jiřı́ Wackermann and Peter P{\"u}tz and Carsten Allefeld},
  journal={Cortex},
  year={2008},
  volume={44},
  pages={1364-1378}
}
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 visual or multi-modal ganzfeld induction are explained. The spectrum of ganzfeld-induced phenomena… Expand
Electrophysiological correlates of flicker-induced color hallucinations
TLDR
It is argued that decreasing activity in the lower alpha band acts as a gating mechanism, inducing a switch in perception between different colors, and the increasing gamma activation may correlate with the formation of a coherent conscious percept. Expand
Altered states phenomena induced by visual flicker light stimulation
TLDR
The data demonstrate that flicker light stimulation is capable of inducing visual effects with an intensity rated to be similar in strength to effects induced by psychedelic substances and thereby support the investigation of potentially shared underlying neuronal mechanisms. Expand
Neuroimaging and EEG-based explorations of cerebral substrates for suprapentasensory perception: A critical appraisal of recent experimental literature
TLDR
An examination of investigations aimed at identifying SPS-associated neurologic substrates critically reviews recently published literature covering EEG studies of reported perceptions of "sensed presence" and ganzfeld-induced imagery, neuronuclear imaging studies of experimentally induced experiences considered to be explicitly "religious" or "spiritual," and brain imaging studies that seek to understand neurologic correlates of individuals' proneness to reporting such experiences. Expand
The multimodal Ganzfeld-induced altered state of consciousness induces decreased thalamo-cortical coupling
TLDR
The Ganzfeld-induced ASC was characterized by increased eigenvector centrality in core regions of the default mode network (DMN), which can be interpreted as an imbalance of sensory bottom-up signaling and internally-generated top-down signaling. Expand
The Ganzfeld experience—A stably inducible altered state of consciousness: Effects of different auditory homogenizations
TLDR
The combination of a standardized psychometric assessment, ratings on subjective time perception, as well as open reports prove the Ganzfeld-induced effects as being stable and effects within each participant as highly replicable, and therefore well suited for experimental purposes. Expand
The Influence of Hypnotizability and Dissociation on Ganzfeld Experiences and Mind-Wandering
Many studies have shown that people report unusual experiences when their senses are exposed to unstructured, monotonous stimuli. However, individual differences in responsiveness are poorlyExpand
Electrophysiological and phenomenological effects of short-term immersion in an altered sensory environment
TLDR
It is suggested that alpha-band electroencephalogram (EEG) dynamics signal internally oriented mentation in response to brief perceptual deprivation indicates diminished brain arousal in individuals with faster alpha oscillations. Expand
On the neurobiology of hallucinations.
  • P. Boksa
  • Medicine, Psychology
  • Journal of psychiatry & neuroscience : JPN
  • 2009
TLDR
It is unknown at present whether hallucinations are generated by similar mechanisms in patients and in healthy people, but it would seem that hallucinations might be a relatively discrete and precisely defined symptom, and therefore amenable to understanding the brain mechanisms involved. Expand
Neurophysiological studies of auditory verbal hallucinations.
TLDR
It is concluded that efforts to understand the pathophysiology of AVH using EEG and MEG have been hindered by poor anatomical resolution of the EEG andMEG measures, poor assessment of symptoms, poor understanding of the phenomenon, poor models of the phenomena, decoupling of the symptoms from the neurophysiology due to medications and comorbidites, and the possibility that the schizophrenia diagnosis breeds truer than the symptoms it comprises. Expand
Red visual stimulation in the Ganzfeld leads to a relative overestimation of duration compared to green.
TLDR
Multiple path analyses revealed that the effect of color on estimated duration is completely mediated through higher arousal levels during the red Ganzfeld session, which generates a longer subjective estimate of duration. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 121 REFERENCES
EEG correlates of multimodal ganzfeld induced hallucinatory imagery.
  • Peter Pütz, M. Braeunig, J. Wackermann
  • Psychology, Medicine
  • International journal of psychophysiology : official journal of the International Organization of Psychophysiology
  • 2006
TLDR
Results indicate that the acceleration of alpha activity is a nonspecific effect of MMGF, and the tri-phasic profile of faster alpha activity seems to be a specific correlate of the retrieval and transformation of memory content in ganzfeld imagery. Expand
Brain electrical activity and subjective experience during altered states of consciousness: ganzfeld and hypnagogic states.
TLDR
Hypnagogic and ganzfeld-induced states should be conceived as special cases of a broader class of 'hypnagoid' phenomena, which can occur in various global functional states of the brain. Expand
Hypnagogic and Hypnopompic Hallucinations during Sleep Paralysis: Neurological and Cultural Construction of the Night-Mare
TLDR
A three-factor structural model of HHEs based on their relations both to cultural narratives and REM neurophysiology is developed and tested with several large samples and central features of the model developed here are consistent with recent work on hallucinations associated with hypnosis and schizophrenia. Expand
Detailed Analyses of Ganzfeld Phenomena as Perceptual Events in Stimulus-Reductive Situations
Experiment 1 reexamined in detail conscious experiences in Ganzfeld situations with homogeneous light (red, green, or blue). Subjects were instructed to report everything, including phenomenaExpand
Altered states of consciousness.
  • A. Ludwig
  • Psychology, Medicine
  • Archives of general psychiatry
  • 1966
TLDR
It is the present intention to integrate and discuss current knowledge regarding various altered states of consciousness in an effort to determine (a) the conditions necessary for their emergence, (b) the factors which influence their outward manifestations, (c) their relatedness and/or common denominators, and (d) the adaptive or maladaptive functions which these states may serve for man. Expand
Neuroimaging of hallucinations: a review of the literature
TLDR
Despite small sample sizes and methodological differences, several studies describe similar results: hallucinations are associated with sensory modality-specific activation in cerebral areas involved in normal sensory processing and neural activation may be specifically related to distinct phenomenological features of the hallucinatory experience. Expand
Spontaneous conscious covert cognition states and brain electric spectral states in canonical correlations.
  • D. Lehmann, P. Grass, B. Meier
  • Psychology, Medicine
  • International journal of psychophysiology : official journal of the International Organization of Psychophysiology
  • 1995
TLDR
The results demonstrate ruleful correspondences between EEG states and spontaneous, conscious, covert, cognitive-emotional states in a no-input, no-task, no response paradigm. Expand
Psychobiology of altered states of consciousness.
TLDR
The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Expand
Hallucinations in schizophrenia, sensory impairment, and brain disease: A unifying model
TLDR
A unified pathophysiological framework for hallucinations in neurological and psychiatric conditions is proposed, which integrates previously unrelated neurobiological and psychological findings. Expand
Why people see things that are not there: A novel Perception and Attention Deficit model for recurrent complex visual hallucinations
TLDR
A novel Perception and Attention Deficit (PAD) model for RCVH is proposed, suggesting that a combination of impaired attentional binding and poor sensory activation of a correct proto-object, in conjunction with a relatively intact scene representation, allows the intrusion of a hallucinatory proto- object into a scene perception. Expand
...
1
2
3
4
5
...