Open for discussion and exchange of views.
The article explains some of the experiences of RSE students plus disciplines such as C & E. This is for people who are looking for a scientific explanation. I do not intend to start a debate on whether out of body or near death experiences are real or imagined.
http://www.mp.uni-tuebingen.de/mp/filea ... 05-ASC.pdf
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The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. 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. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.
From Page 101, Hypnagogic States
Hypnagogic states are transient states of decreased wakefulness characterized by short episodes of dreamlike sensory experience. These phenomena were first described by J. Mu?ller (1826/1967) as ?fantastic visual phenomena? (p. 20ff) occurring usually, but not exclusively, at sleep onset. Maury (1848) coined for them the term hypnagogic, from Greek hypnos (sleep) and agogo (I bring). Schacter (1976) described them as ?dreamlets.? Subjects usually report short visual percepts like faces, landscapes, and natural or social scenes that may or may not be related to previous daytime experience. These percepts may be of pseudohallucinatory (i.e., with preserved insight of unreality) or truly hallucinatory (i.e., experienced as if real) character. In contrast to dreams, hypnagogic experiences are usually rather static, without narrative content, and the subject is not involved as an actor (cf. Sleep and Dreaming section). Hypnagogic states have been extensively studied for their
peculiar phenomenology (Leaning, 1925; Leroy, 1933; Linschoten, 1955) and symbolic character (Silberer, 1909). Hori, Hayashi, and Morikawa (1994) conceived of hypnagogic states as a unique period that cannot be accurately categorized as either waking or sleeping, and with unique behavioral, electrophysiological, and subjective characteristics. Similar phenomena occurring at the transition from sleep to wakefulness are called hypnopompic (Myers, 1904); here, however, it is difficult to differentiate hypnagogic imagery from remnants of dream imagery. Hypnagogic-like phenomena may also occur in daytime periods of reduced wakefulness and possibly superimposed over adequate sensory perceptions of the environment (cf. Mavromatis, 1987; Schacter, 1976; Sherwood, 2002). Subjective experience in hypnagogic states comprises
vivid, mostly very brief episodes of usually visual (86%) and acoustical (8%) imagery with other sensory modalities occurring less frequently and with an average recall rate of 35%. There is more awareness of the real situation in hypnagogic states than in dreaming (Hori et al., 1994). The prevalence for frequent hypnagogic states is estimated at 37% (Ohayon, Priest, Caulet, & Guilleminault, 1996). Behavioral correlates are sparse, for example, leg or arm jerks (?sleep starts?) associated with illusionary body movements (American Sleep Disorders Association, 1990; Sherwood, 2002). As for physiological correlates, an association between short flashes of dreamlike imagery and drop-offs in alpha EEG activity was first noticed by Davis et al. (1937). By definition, hypnagogic states are related to sleep onset, that is, Sleep Stage 1 according to Rechtschaffen and Kales (1968), but may occur even with presleep alpha EEG (Foulkes & Schmidt, 1983; Foulkes & Vogel, 1965). Kuhlo and Lehmann (1964) studied hypnagogic states and their EEG correlates during drowsiness and sleep onset: Spontaneous, transient, fragmentary nonemotional visual and auditory impressions of varying complexity were reported that were mostly experienced as unreal and were associated
with flattened or decelerated alpha and/or slow theta EEG activity; the authors postulated a gradual progression from hypnagogic
hallucinations to fragmentary dreams (cf. Lehmann et al., 1995). Systematic comparisons of hypnagogic phenomena with perceptual
phenomena that were observed with reduced sensory input (cf. section on sensory homogenization and ?ganzfeld?) led us to
conceptualize a broader class of ?hypnagoid? phenomena (Wackermann, Pu?tz, Bu?chi, Strauch, & Lehmann, 2000, 2002), of which
the true hypnagogic hallucinations are a special case, and in spite of distinctly different brain functional states at sleep onset and in
ganzfeld, subjective experience exhibits very similar features.
From Page 102, Near-Death Experiences
The typical core elements of near-death experiences include (a) a feeling of peacefulness and well-being, (b) a separation from the body (out-of-body experience), (c) a dark tunnel experience, (d) a brilliant light associated with mystical feelings of love and union, and (e) a heavenly landscape (often relatives, religious figures, or beings of light appear and finally initiate the return to the body). Other elements are the hearing of music, a slowing of time and speeding of thoughts, and a panoramic life review. The incidence of near-death experiences is estimated to lie between 10% and 50% of all near-death situations and is independent of gender, age, and profession (Schroeter-Kunhardt, 1993). The circumstances of the close brush with death (e.g., from illness, accident, suicide, or anesthetics) have only a minor influence on the occurrence and features of the near-death experiences (Greyson, 2000). This invariance suggests a specific neurophysiological mechanism taking
place in the dying brain. Accordingly, several hypotheses have been formulated regarding the neurophysiological processes (cerebral
anoxia, depletion of neurotransmitter reservoirs, release of endorphins, general disinhibition of the brain) and structures (limbic system, septohippocampal formation, temporal lobes, visual cortex) that have been involved in the generation of near-death experiences (Blackmore, 1996; Morse, Venecia, & Milstein, 1989; Saavedra-Aguilar & Gomez-Jeria, 1989).
From Page 104, (C & E discipline) Respiratory Maneuvers
Among methods of inducing ASC, changes in breathing patterns are of significant interest. Most breath manipulations are based primarily on Yoga and Zen practices, and they include passive breath mindfulness and breathing (Lichstein, 1988). This requires the trainee to focus attention on breathing and allows slow and shallow respiration to emerge. In meditation techniques, breath manipulation works with mantra chanting, counting, and maintaining a fixed gaze on an external object or cue word. Deep breathing consists of taking a deep breath, retaining the breath, and exhaling slowly. The method of slow diaphragmatic breathing and paced respiration is also a procedure that alone or in combination with
other meditative techniques leads to tension reduction in body musculature and to the balance of neurovegetative regulatory systems. The mechanisms of these breathing techniques are based on increases in pCO2, resulting in hypercapnia. Breath holding (for 5?10 s) and shallow, slow breathing producing hypoventilation are two methods with which to create mild hypercapnia including a slow heart rate, dilation of the peripheral vasculature, stimulation of gastric secretion, depressed cortical activity, and a global sensation of mild somnolence (Lichstein, 1988). This normally occurs in the transition from wakefulness to drowsiness, in hypnagogic states, and in sound sleep (Naifeh, Kamiya, & Sweet, 1982).
Similar hypercapnia effects can also be evoked by inhaling a CO2-enriched breathing air mixture. Meduna (1950) reported that hypercapnia may result in typical near-death experiences, such as bodily detachment and the perception of being drawn toward a bright light. Both phenomena were associated with power increases in EEG low-frequency bands. A recent study by Terekhin (1996), however, failed to confirm these findings. Here a CO2-enriched breathing air mixture did not lead to slow-wave EEG and concomitant experiences of obnubilation, depersonalization, and
derealization. These differences may largely be traced back to the varying amount and duration of inhaling a CO2-enriched air mixture.
Breathing has also been manipulated by techniques that lead to hypocapnia, such as shamanism practices, ritual dances, holotropic breathing (Grof, 1976), and rebirthing. In this context, breathing plays a pivotal role. Involuntary hyperventilation often accompanies hard physical work, long-lasting emotional tension, and enduring mental effort. Hyperventilation is also involved in panic attacks and their clinical symptoms (e.g., dyspnea, vertigo, palpitations, chest pain, numbness or tingling, depersonalization, fear of losing control; W. N. Gardner, 1996). When healthy subjects were required to voluntarily hyperventilate, 83% experienced syncopes marked by an incipient fall (Lempert, Bauer, & Schmidt, 1994).
Arrhythmical mycloni occurred in 90% of 42 syncopal episodes. Visual (e.g., colored patches, bright lights, gray haze) and auditory (e.g., roaring noises, screaming) hallucinations were reported by 60%. Commonly, subjects described a state of impaired external awareness, disorientation, weightlessness, detachment, and loss of voluntary motor control.
Forced respiration during hyperventilation has rapid and farranging physiological effects via its alteration of pH and depletion of CO2 in the body, resulting in acute or chronic respiratory alkalosis (hypocapnia). The cerebral circulation is highly sensitive to respiratory alkalosis, which develops within the first 15?20 s of hyperventilation. As a consequence, pronounced hypocapnia (PaCO2/22 mmHg or less) affects regional and local cerebral hemodynamics, circulation, and oxygen supply. Hyperventilationinduced changes in EEG (slow waves in the frontal leads, hypersynchronization) were found to be identical to the hypoxia-induced changes, such as arteriole vasospasm, ischemic foci, and redistribution of the blood flow between various brain regions (Paulson & Sharbrough, 1974). In both cases, fainting, obnubilation, depersonalization, and similar forms of ASC may occur.
The interaction between respiratory maneuvers, such as hyperventilation and alteration of consciousness, can also be considered under clinical perspectives. Hyperventilation represents a wellestablished EEG activation procedure aimed at enhancing epileptiform discharges, which may result in impairment of consciousness (absence). Typical ictal absences have been precipitated by hyperventilation in about 90% of untreated patients (Panayiotopoulos, 2001).
From Page 107, Rhythm-Induced Trance (Drumming and Dancing)
Drumming and dancing have been practiced since ancient times to induce altered states and are still common today. They may result in trancelike states characterized by a ?narrowing of awareness of immediate surroundings, or unusually narrow and selective focusing on environmental stimuli? and by ?stereotyped behaviors or movements that are experienced as being beyond one?s control? (American Psychiatric Association, 1994, p. 729). In the case of drumming and dancing, the rhythmic body movements become synchronized with the beat and finally seem to happen automatically, without effort or voluntary control. Self-reflective thinking ceases when the subject becomes increasingly absorbed in the action. In addition, alterations also include a distortion of the time sense, unusual bodily sensations (e.g., feeling light, warm, energized), vivid imagery, and strong positive emotions (e.g., joy, happiness, ecstasy) in conjunction with the impression of becoming
one with the rhythm.
In contrast to the ubiquity of the phenomena, modern science has scarcely investigated the psychobiological foundations of these human activities. Neher (1961, 1962) was the first to study the effects of monotonous drumming on the EEG. He found that drum beats (3?8 Hz) can induce EEG waves of the same frequency (?auditory driving?), and he speculated that this phenomenon may be responsible for the facilitation of trance states. Later on, the role of physiological stimulation was questioned by Rouget (1980), who emphasized the impact of the social setting. This issue was further explored by Maxfield (1990), who studied the effects of different beat rhythms on the EEG and subjective experiences. She
found more theta EEG activity while the subjects were listening to rhythmic monotonous and patterned drum beats than when they heard unstructured beat sequences. The alterations in consciousness included changes in time sense and body image, enhanced imagery, and other experiences resembling descriptions of a shaman?s journey. In a study by Maurer, Kumar, Woodside, and Pekala (1997), relaxation and similar shamanic-type experiences (e.g., dissociation from the body, tunnel experiences) were evoked by monotonous drumming, especially in medium and highly hypnotizable subjects.
Besides rhythmical auditory stimulation, the social setting, and personality traits (e.g., absorption), a fourth factor?namely, the rhythmic body movements during drumming and dancing?may play an important role for trance induction. Rhythmic body movements are accompanied by recurrent shifts in body fluids, especially in the blood. In addition, respiration tends to synchronize with movements and induces the heart rate oscillations known as respiratory sinus arrhythmia. In this way, rhythmic movements may result in a respiratory? cardiovascular synchronization with increased blood pressure oscillations that stimulate the carotid baroreceptors. The effects of baroreceptor stimulation are not confined to a slowing of the heart rate; they also reduce cortical arousal and excitability (Rau, Pauli, Brody, Elbert, & Birbaumer, 1993; Vaitl & Gruppe, 1995). Many effects of barostimulation?like augmented pain thresholds, increased theta activity, and reduced muscular reflexes?resemble typical features of trance states.
From Page 113, (Also explains out of body experience) Epilepsy
Cortical seizures with their typical pattern of paroxysmal activity are an excellent example of the tight connection between neuroelectric (pathological) changes and conscious experience: Location, extension, and intensity of the neurographic signs are correlated with the quality and intensity of the psychological event before, during, and after the seizures.
The common underlying neurophysiological principles of many different types of epileptic seizures are hypersynchronizations of extensive neuronal tissue. Loss of consciousness occurs only if large enough cortical tissue in critical areas is involved and the hypersynchronization causes interruption of normal functioning of the involved neuronal pool or deactivates structures involved in regulation of consciousness and attention (see Table 3). Partial seizures concern local areas of the brain and are excellent examples of the ?modularity? of consciousness and the underlying brain mechanisms (for a review, see Niedermeyer & Lopes da Silva, 1999).
Dependent on the anatomical origin of the paroxysmal neuroelectric discharge, patients experience motor activity, sensory symptoms, or cognitive, emotional, or autonomic alterations: Particular seizures of the medial temporal lobe with the underlying hippocampal and other limbic structures such as the amygdala lead to characteristic and well-described ASC such as dreamy states, distortions of time sense (Bancaud, Brunet-Bourgin, Chauvel, & Halgren, 1994; Vuilleumier, Despland, Assal, & Regli, 1997), religious experience (Saver & Rabin, 1997), and altered affect
(Tisher et al., 1993). Visual and auditory hallucinations are particularly frequent after discharges of the memory structures of the medial temporal lobe and the connected hippocampal and cortical regions. Stored memories are excited together with emotional responses in a structured or seemingly chaotic fashion (Bien et al., 2000; Brinciotti, Di Sabato, Matricardi, & Guidetti, 2000; Carmant et al., 1996; Gloor, 1990). Out-of-body experience and autoscopy (seeing one?s body in extrapersonal space) are thought to be due to a paroxysmal dysfunction of the temporoparietal junction in a state of partially and briefly impaired consciousness (Blanke, Landis, Spinelli, & Seeck, 2004).