TOPOGRAPHIC BRAIN MAPPING of UFO EXPERIENCERS, By NORMAN S. DON, Neuroscientist, GILDA MOURA of the Kairos Foundation & the University of Illinois at Chicago
Although those of you who know me, will immediately comprehend why I am so profoundly moved by any material associated with the brain, it is always a great pleasure to find material that has significant relevance to the Experiencer/Alien Abduction Phenomena. I find the conclusions of this paper very significant because of its clear indication that something very profound is happening to people who are experiencing these paranormal events. This paper is an indication that there are people, like myself and others, who experience physiological effects within their brains after what they perceive as contact with Extraterrestrial Beings and Ufos. This paper is a physical, external confirmation for those of us who have been having these experiences throughout our lives, indicating that something concrete and physical is occurring to our brains.
For myself, I have already experienced what I believe is an understanding, of the integration that needs to occur between the body, mind & soul, in order for human beings to actually evolve. This evolutionary process must occur in the physical body on every level, in order to have any significance or value within this, the physical reality or this dimension.
Further, this paper displays a clear correlation between brain activity and those paranormal events, which may be useful in indicating that we are being physiologically altered and physically impacted by our contact with Extraterrestrial Life and/or Ufo Encounters.
I hope you all, will find this paper as significant as I have. I am grateful to be able to share this paper. Joy S. Gilbert
Journal of Scientific Exploration, Vol. I I, No. 4, pp. 435-453, 1997 OS92-33 10/97 © 1997 Society for Scientific Exploration “Topographic Brain Mapping of UFO Experiencers”. NORMAN S. DON, Neuroscientist, Kairos Foundation and University of Illinois at Chicago, 1107 Wilmette Ave.. #174. Wilmette, IL 60091 norman.s.don@ uic.edu
Kairoa Foundation, Caixa Postal 14520,
CEP 2241’2-000, Rio de Janeiro, Brazil
Abstract — A cohort of Brazilian subjects, claiming experiences with UFOs involving contact or abduction, were selected for topographic brain mapping. One of the most important selection criteria was the ability to enter into a self-reported, non-ordinary state of consciousness or trance that developed spontaneously after their abduction or contact experiences. Analysis of their EEGs revealed that all subjects entered voluntarily into an hyper aroused trance. In this state, they maintained a condition of muscular relaxation and immobility while their EEGs exhibited high frequency (beta) activity at all 19 electrode sites, but with maximum activity at the prefrontal and adjacent loci.
Inspection of the EEGs from the prefrontal/frontal sites revealed intermittent trains of rhythmic, approximately 40 Hz activity, attaining very high amplitudes, at times exceeding 40 microvolts.
This activity was distinct in morphology and frequency from faster, usually concurrent activity, probably attributable to scalp muscle discharge (EMG). Analysis of 40 Hz, midline scalp activity, statistically controlling for the effects of EMG, revealed significantly more 40 Hz activity in trance than in baseline (p < .006). Also, the dominant alpha frequency increased during trance (p < .01). Both EEG findings suggest the occurrence of a state of hyper arousal.
There was no evidence of epileptiform discharges in our data or clinical indications of possible epilepsy. Also, there was no brain activity suggestive of psychopathology, particularly schizophrenia, nor were there clinical indications of psychopathology.
The EEG results were related to the physiological effects of highly focused attention and recent findings in neuroscience. Also noted were similarities to advanced meditative states and differences from psychopathology.
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“Abduction,” or “close encounters of the fourth kind,” involves kidnapping, either in a conscious or unconscious state, and the performance of medical-like procedures on the abductee. The sequelae of these reported abductions usually involve significant psychological trauma.
In the preliminary phase of our investigations, which involved 10 UFO experiencers who were not in the final sample of 13, the data suggested that these subjects could voluntarily self-induce a state of hyper aroused trance, with high frequency, high amplitude brain waves, probably not attributable to scalp muscle artifact. For reports on the early phase of this work, please see Moura (1994a, p. 186-190; 1994b, p. 485-492) and Don (1994, p. 493-496).
We chose to investigate the UFO experiencers because they evidenced advanced stages of hyperaroused trance not found in Brazilian mystics and rare even among experienced yogi meditators from India.
The purpose of this study was to determine whether the frequency and amplitude characteristics (as evidenced in EEG recordings) of the subjects’ brain function while in trance differed significantly from baseline, pre-trance measurements. Also, if such differences existed, we wanted to compare our results with EEG studies done on people who meditate. The veridicality of the subjects’ experiences was not addressed.’
For an introduction to the literature on the abduction/contact phenomenon, see Moura (1996/1992), Mack (1994a), Sprinkle (1994), and Pritchard et al. (1994).
Within these broad frequency bands, there are different frequency sub groups associated with differing states of arousal and brain function, each with
Recently, experiments involving PET scans have shown that different parts of the brain are activated by true and false memories of recently spoken words (Schacterc/a/., 1996). Additionally, PET scans of survivors of trauma reveal a differential brain response under conditions of symptom provocation compared to control conditions (Rauch et ul., 1996). Therefore, beyond the issue of whether or not there is an altered state of brain function during the trances, it may in the future also be possible to examine whether or not brain function characteristics tend to support or disconfirm the veridicality of at least some components of abduction memories.
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There is considerable individual variance in alpha wave amplitude; it is reported that 66 of subjects have 20-60 microvolts of activity, whereas 6 of subjects exceed 60 microvolts (Simonova et al., 1967).
“Beta” rhythms are faster than 13 Hz, and usually predominate the EEG of the awake, alert, adult subject with open eyes, with amplitudes typically below 20 microvolts. The beta range can be subdivided into beta I (14-30 Hz) and beta II for rhythms above approximately 30 Hz; the latter are sometimes termed “gamma” rhythms.
A. Brain Function and High Frequency Brain Waves
Animal studies with implanted electrodes, magneto encephalographic and scalp recorded EEG studies with humans, and computer simulations, suggest that 40 Hz activity plays a central role in cognition and sensory processing (Sheer, 1984; Llinas & Pare, 1991; Llinas & Ribary, 1992, 1993; Steriade et al., 1991, 1993).
Further, the thalamic intralaminar nuclei, part of the thalamo-cortical circuits involved in the generation of 40 Hz activity, along with the midbrain reticular formation, have been shown in PET studies to be activated by attentional processes (Kinomura et al., 1996). Highly focused attention is considered necessary in the generation of certain advanced meditative states, which we would therefore expect to be accompanied by broad band 40 Hz waves in the EEG.
Therefore, while it is well-known that beta waves are associated with states of alert wakefulness, recent work suggests that the higher-frequency beta rhythms are associated with heightened levels of brain function, or more broadly, consciousness.
438 N. Don & G. Moura and Gastaut (1957) reported an EEG study conducted in India. Seven members of a spiritual community, practicing Kriya yoga, were measured in 20 recording sessions. However, Das and Gastaut reported only data from the “guru,” the spiritual leader of the community, apparently because of his extraordinary ASC.
He entered twice into a state of yogic ecstasy (“1’extase yogique”) or “samadhi,” during which he was physiologically hyper aroused, as indicated by the EEG and EKG, while the EMG recorded from the quadriceps remained flat (c/. Kugler, 1982). Among other findings, the subject’s brain waves were reported to be 20-30 Hz and 40 Hz, generally distributed over both hemispheres, with amplitudes in the range of 30-50 microvolts.
This case study remains a landmark in the psychophysiological literature on meditation since it is the only one examining a very advanced subject in the state of yogic ecstasy or “samadhi,” the culmination of meditation, which is considered to be the direct, conscious experience of the godhead (Eliade, 1958, p. 91-95). Since its publication some 40 years ago, even though it is just a single-case study, it apparently has not been challenged seriously. At that time, Henri Gastaut was widely considered to be the world’s foremost epileptologist. It should be noted that Das and Gastaut used the terms yogic ecstasy and “samadhi” synonymously, whereas other sources, such as Fischer (1971) and Eliade (1964, p. 417), differentiate between ecstasy and “samadhi.” Fischer, however, states that there is ultimately a joining of these two states at a certain, advanced point in the meditative process.
In a conference presentation in 1960 (cited in West, 1980), Fenwick reported three meditators practicing a mantra meditation (similar to the method of Transcendental Meditation). In the later stages of meditation, theta bursts were observed accompanied by beta activity.
The next study reporting high frequency brain activity (20 and 40 Hz) was by Banquet (1973). This cortical activity was found in four advanced Transcendental Meditation (TM) practitioners during the state of “transcendence,” as defined in TM.
The 20 Hz beta amplitude was very high (30-60 microvolts) while the 40 Hz activity was just a few microvolts. The high frequencies predominated in the anterior channels but were found sometimes in all eight channels recorded.
However, since Banquet’s studies, recent experiments have failed to replicate the presence of high frequency beta among TM meditators (F. T. Travis, personal communication, April 12, 1996).
The fourth and last study reporting fast beta waves during meditation was by Benson et al. (1990), who measured three Tibetan Buddhist monks in Sikkim while they practiced “g Tum-mo” yoga. They found that resting metabolism was raised voluntarily (a maximum of 61) or lowered (a maximum of 64).
In one of the three subjects, EEG power in the 12-35 Hz band (a maximum frequency recorded) increased over 50.
Additionally, Surwillo and Hobson (1978) found acceleration of the dominant alpha frequency with Christians during prayer and with a Moslem subject during Sufi meditation. Das and Gastaut also found this effect. –
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Therefore, while data from a very large number of meditators in hypo aroused states such as TM have been reported in the past 25 years (for a review see Jevning et al. (1992)), there are EEG reports of only a few subjects in an hyper aroused ASC.
However, hyper aroused altered states are well known to anthropologists from their study of some native peoples (Bateson & Meade, 1952; Deren, 1953; Rouch, 1960; Jorgensen, 1972). Experiences of very bright light are often associated with these trances and are a well-known characteristic of advanced meditative and mystical states (Eliade, 1964, p. 60-62).
A common experience among our subjects when in trance was of a very strong light near the forehead. It therefore appears likely that this experience is another indicator of hyper aroused, non-ordinary states of consciousness.
Ring (1992) has reported the incidence of very bright, white light during the near-death experience. He has proposed that the “kundalini” syndrome, which is elucidated in tantric yoga (Eliade, 1958, p. 134), is the process common to both UFO and near-death experiences. Moura (1996/1992) has argued that while the “kundalini” process is involved in UFO experiences, it does not adequately account for all the reported phenomena. Das and Gastaut also related the hyper aroused ecstasy and “samadhi” of their yogic adept, or “guru,” to the “kundalini” process of yoga.
Hence, although there have been many reports of behaviors or mental states suggestive of hyper aroused trance, there is a notable lack of advanced subjects capable of entering these states under laboratory conditions or controlled conditions in field settings.
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B. EEG Recording Procedure The investigators traveled extensively in Brazil with a portable, 23-channel EEG and computer in order to gather the data. Recording sessions took place in a wide variety of field settings. Each session began with the recording of resting baselines with eyes open and closed. Following this, subjects were requested to enter their special state of consciousness.
off at 128 Hz with a 48 dB roll off/octave) plus five additional channels and related software for data editing and analysis.
The sampling rate was 512/second for 10 subjects and 256/second for an additional 3 subjects. Electrodes were applied using an electrode cap and conducting gel made by Electro-Cap International, Inc. This consisted of an elastic skull cap with tin electrodes pre-positioned over the 19 International 10-20 scalp electrode sites with a forehead ground. Reference electrodes were applied to the left and right earlobes and linked.
For most sessions, two addition-al electrodes were affixed to the center of the forehead, approximately one centimeter apart, for bipolar recording of frontalis EMG, or over the left masseter muscle. Over all testing sessions, the impedances at the scalp, ground and reference electrodes were usually kept below 3 k ohms.
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The records showed the usual inter-subject variability of amplitude and varying amounts of alpha rhythms.
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Please see Figure 1.
Fig. 1. Raw EEG tracings plotted at 30 mm/sec from a representative abductee during a pretrance baseline (left column). Channel names are shown at far left. Scale bars for 100 (J.V amplitude and 1 second duration are provided at the top of the figure. A 0.1 second segment of channel Fp 1, over the left pre-frontal scalp, during trance is zoomed (inset) to reveal a nearly sinusoidal rhythm of approximately 50 (lV amplitude at 40 Hz. Scalp recorded muscle artifact is usually irregular and arrhythmic.
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Fig. 2. Pre-frontal EEG of a second abductee showing the waxing and waning of brain activation during stages of trance. The number of seconds from commencement of the trance record are shown in parentheses.
Power spectra were computed on arti-fact-free EEG epochs by a digital signal processing chip and associated hardware in the Lexicor NeuroSearch-24. For each of 19 channels, log power density in the theta (4-8 Hz), alpha (8-14 Hz), beta I (14-30 Hz), and beta II (30-50 Hz), and the 70-128 Hz frequency bands was computed.3 Because at higher frequencies (above 14 Hz and especially above 30 Hz) the EEG may also contain signals from scalp muscle discharge, it is necessary to control for EMG activity when computing the statistical effects of trance compared to baseline.
See Appendix I for a discussion of the methodology used.
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It is well known that temporal lobe instabilities lead to disturbances of conscious experience (Fenwick, 1983; Fenwick et al., 1985). Persinger (1989a, 1989b) has hypothesized that some people with such labile brain function, especially when exposed to increases in geomagnetic radiation, will have unusual conscious experiences such as of nonhuman beings and UFOs.
A more likely explanation for these experiences in adults with no history of physical trauma to the brain is complex partial epileptic seizures. These most often occur in the temporal lobes, the limbic system, or are temper limbic.
During epileptic crises, there is typically a narrowing of the field of consciousness with delusions, hallucinations, and distortions in visual reality.
None of the thirteen people in this study has been diagnosed as epileptic and none was medicated. Because of their experiences, several had full diagnostic neurological evaluations prior to involvement in this study, which found no evidence of epilepsy. In an extended review of our physiological data and subjects’ histories, our Brazilian epileptologist consultant concluded that they did not present any critical phenomena suggestive of epilepsy (H. Bello, personal communications, March – October, 1996). Additionally, unlike epileptic patients, our subjects voluntarily entered and left the state of altered brain function.
In order to obtain a second opinion regarding the possible presence of epileptiform EEG patterns during trance, we submitted samples of our data for examination by a senior-level, American neurologist specializing in the EEG and diagnosis of epilepsy. We were informed that there was no epileptiform activity present in those EEGs (J. R. Hughes, personal communication, June 24, 1996).
Both neurologists concluded that the rhythmic, approximately 40 Hz activity appeared to be cortical in origin. Additionally, our Brazilian consultant.
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Moreover, the EEG results observed for the present sample of UFO experiencers displayed a different pattern than is typically seen in depression or hysterical attack (Niedermeyer & Lopes da Silva, 1993, p. 345, 569-570). Most potentially relevant are the EEG findings from studies of schizophrenia.4 Since the initial reports of Davis (1940), there have been numerous observations of increased fast beta activity in schizophrenic patients relative to controls which may sometimes have overlapped with the beta band studied here (For review, see Itil, 1977).
However, the pattern of the EEG findings for our UFO experiencers is differentiated from the findings reported for schizophrenics. For the UFO experiencers, only the amount of fast beta activity was affected, whereas in schizophrenics, the amount of activity in lower frequency bands, including delta, theta, alpha, and low beta, may also be affected (Itil et al., 1972; Morstyn, etal., 1983; Gattaz etal., 1992).
Further, the topographic distribution of the fast beta activity appeared to differentiate our UFO experiencers from schizophrenics, in that the beta activity was observed predominately over the frontal scalp in our subjects but was observed mostly at sites posterior to the frontal scalp in schizophrenics (e.g., Morstyn etal., 1983; Gattaz et al., 1992).5 Finally, our subjects could voluntarily commence and terminate the high frequency activity which was only present in the trance condition. Voluntary control of this activity is not found in schizophrenics.
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1) a statistically significant increase in power for 30-50 Hz, high amplitude brain waves, probably not due entirely to scalp muscle discharge;
These information substances can modulate the action of neural systems of the brain so as to encode memory and learning in a special manner.” Therefore, it is likely that 40 Hz (and possibly higher frequency) brain activity was associated with the encoding of the reported experiences, as well as its recall. In order to re-experience contact/abduction, the state of brain function associated with the high-frequency rhythms must be reinstated.
Our results differ from Banquet’s 1973 report on advanced TM meditators in their deepest stage of practice, in which high power 20 Hz activity was observed, while 40 Hz activity was present but much weaker. In our data, 20 Hz effects were absent while broad band 40 Hz effects were robust.
All our subjects were able to enter an extreme hyper aroused ASC, showing EEG similarities to the state reported by Das and Gastaut in their one advanced subject as yogic ecstasy or “samadhi.” As we noted previously, although Das and Gastaut did not differentiate between these two states, they are usually not considered to be synonymous. We submit that our subjects were in an ecstatic state.
Fischer (1971) assigns extreme hyper aroused trance to the ecstatic state. Also, the experience of “blissful excitement” (George, 1995, p. 82), a common characteristic of the ecstatic state, was reported by our subjects. They also related feeling that they were linked to a higher consciousness, and sometimes being connected with a non-human being or even with God.
Mack (1994a) and Moura (1996/1992) have reported on the ecstatic dimension of this class of subject. However, in contrast to the present study, although there are many accounts of the mystical experiences of yogis, there is no mention of abduction or UFO contact, suggesting that while there are
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The ability of the experiencers to enter trance developed after their reported contact with non-human beings and was not the fruit of years of intense practice of yoga or meditation. Whereas most of Das and Gastaut’s seven Indian yogis had been practicing five to ten years, in 20 data-recording sessions with this group, only the spiritual head of the community attained the hyper aroused state, doing so on two occasions.
Almost all studies in the meditation literature involve hypo aroused states, such as are found in TM and Zen. These are characterized by the physiological slowing of a host of parameters (for a review see Jevning et al., 1992) although Banquet (1973) reported the presence of fast beta predominantly at anterior scalp sites in more advanced TM meditators during the state they term “transcendence.” However, as noted earlier, that beta has not been replicable in recent attempts. In contrast to the advanced TM meditators, our subjects did not exhibit increased beta I power, but did have a large increase of 40 Hz (and broad band 30-50 Hz beta II) power.
Also noted earlier, PET scans during focused attention by humans have revealed an activation of the midbrain reticular formation and the thalamic intralaminar nuclei (Kinomwaetal., 1996). Corollary to this finding, Llinas and Pare (1991) and Llinas and Ribary (1992, 1993) earlier proposed that the thalamic intralaminar nuclei, comprising the diffuse thalamic system, generates 40 Hz activity which integrates corticothalamic activity and so bears importantly on consciousness.
Also, earlier work by Sheer (1984, p. 64-84) found that scalp-recorded 40 Hz was associated with “focused arousal” and learning tasks. Q-sorts, investigating subjective aspects of different brain states, revealed differences between high and low frequency beta.
The descriptors for the experience of 5-10 microvolt 40 Hz were: “attentive, concentrating, effortful, focused, investigating, searching, scrutinizing, studying, thinking, and vigilant.” For low frequency beta (21-31 Hz), the descriptors were: “active, alert, anxious, energetic, excited, exhilarated, lively, restless, stimulated, and tense” (Bird et al., 1978).
It therefore appears that as the focus of attention sharpens, the integrative activity of the diffuse thalamic system increases through the action of 40 Hz brain rhythms. Apparently, when attentional focusing becomes “laser-like,” an extreme state of corticothalamic integration occurs and with it an amplification of normally unconscious brain activity.
At the extremes, either ecstasy or “samadhi,” Fischer (1971) proposed that the constraints on normal, waking consciousness are bridged and a higher-order self or personality prevails which seems to transcend time and space.
While Das and Gastaut’s “guru” had high-amplitude, very high frequency brain activity widely-spread over the scalp, the extreme activation pattern of our subjects was centered on the prefrontal and adjacent loci of the brain, but
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The rarity of the extreme hyper aroused state of ecstasy is further supported by Bagchi and Wenger’s study (1957) in which they recorded EEGs from 14 Indian yogis in a variety of settings, including caves. They found only changes in the alpha rhythms and no evidence of high amplitude fast waves. It is of importance to note that these advanced subjects did not report the experience of yogic ecstasy.
In contrast to this evidence, suggesting the rarity of ecstasy, all our subjects attained this physiologic state. They therefore constitute the largest cohort of subjects reported to this date exhibiting this apparently rare state of brain function. However, these results are correlational, and it awaits further investigation in order to establish a conclusive link between extreme, hyper aroused states of brain function and transcendental experiences.
But in addition to involvement in “super-conscious” states, recent investigations in neuroscience have revealed the significance of high frequency brain rhythms in cognition, learning, attention, sensory processing, and as indicated by our results, state-dependent memory. However our subjects actually came by the ability to enter into their unusual ASC, it is important to point out that all our subjects could do so voluntarily, apparently without practicing for many years or initiation by yogic adepts.
We first wish to thank our research subjects who generously cooperated in this investigation. We also thank Helio Bello, M.D., for the neurological consultations and the large amount of advice, encouragement and support he has given so graciously to the authors of this study. We wish to acknowledge Bruce E. McDonough, Ph.D., for his assistance with the analysis of the data.
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Appendix I — EMG Correction
However, because high amplitude activity over 30 Hz was apparent for most subjects throughout their trance periods, a simple data-exclusion criterion could not be employed. Therefore, in order to avoid potentially biasing the EEG comparisons between the baseline and trance conditions, an effort was made to balance the levels of EMG activity in these two conditions.
EMG balancing between conditions was considered necessary only for analyses of beta activity. Analyses of theta and alpha activity were conducted on unbalanced data. To control for EMG levels between conditions, EMG activity (defined operationally as total power in the 70-128 Hz region of the frequency spectrum) was calculated for each one-half second recording epoch. In accord with Davidson (1988; personal communications, 1994-1995), we assumed that any scalp recorded activity over 70 Hz was solely from muscle activity.
However, there is no reported data on what the upper frequency limit for scalp recorded EEGs actually is, due only to brain activity. Especially with unusual subjects in an hyper aroused trance, the 70 Hz criterion may be arbitrary, and require revision in future research.
Because of limitations of our software, power in the EMG band could be computed only for the 10 subjects whose data were recorded at 512 samples/second. Separately, for each subject and electrode site, log EMG power for trance and baseline was compared by /-test.
Trance epochs showing the highest EMG levels and/or baseline epochs showing the lowest EMG levels were then dropped and remaining epochs compared again; this process continuing iteratively until the log EMG levels were non-significantly different (Mest p > .10).6 For 7 subjects, EMG levels between trance and baseline conditions could be brought into balance in this way at the midline sites Fz, Cz, and Pz. In general, midline sites, especially Cz and Pz, are least affected by scalp muscle discharge.
Other scalp sites could also be balanced for some, but not all, of these subjects. Therefore, in order to maintain a sample size of at least 7 subjects, group analyses of beta activity considered only the 3 midline sites. That the EMG levels in the baseline and trance conditions did not differ for these 7 subjects after balancing was confirmed by 2-factor (condition x scalp site)
”When data are correlated and cannot meet the assumption underlying the /-test that observations be independent, as is the case in the analysis of multiple EEG epochs from a single subject, the statistical significance of the result is likely to be inflated. Thus, the single subject /-test results may be regarded as conservative in the sense that they tend to overstate the extent to which the trance and baseline EMG levels differ for each subject.
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Log transforms were performed on power density data in the EEG bands for epochs remaining after EMG balancing. The log power density of single epochs was then averaged within subjects, separately for each channel and frequency band. Visual inspection of the data histograms suggested that the log power-density distributions were approximately normal.
Questions of EEG power density differences between baseline and trance were examined in 2-factor ANOVAs with repeated measures across electrode site (Fz, Cz, Pz) and condition (baseline, trance). A separate 2-factor ANOVA was performed for each frequency band examined.
Marginal mean log power density in the 30-50 Hz beta II band was observed to be larger in trance (0.13) than during baseline (0.04), F( 1 /6) = 17.57, p = .006. A tendency for beta II to increase from posterior to anterior scalp was also observed, F(2/l2) = 3.26, p = . 114, e = .5655, with marginal mean log power density of 0.22, 0.08, and -0.04, at Fz, Cz, and Pz, respectively.7 The condition by scalp-site interaction was non-significant, F(2/12) = 0.33, p =. 724, e=. 5528.
Marginal mean log power density in the 14-30 Hz beta I band was not different between trance (0.70) and baseline (0.69) conditions, F(/6) = 0.09, p = .780. Neither the main effect of scalp site, F(l/6) = 0.37, p = .699, e = .9598, nor the condition by scalp-site interaction, F(2/l 2) = 0.98, p = .404, e = .6361, were significant for beta I.
Effects of Trance on Alpha and Theta Activity Log power density in the alpha and theta bands was evaluated for all 13 subjects over the occipital scalp sites (01 and 02) in separate 2-factor ANOVAs. It was possible to include all subjects since EMG infiltration into these lower regions of the frequency spectrum is likely to be minimal and, therefore, controlling for EMG levels was regarded as unnecessary.
Gain effects and interactions involving the scalp-site factor were evaluated using the Greenhouse-Geisser adjustment where appropriate. Greenhouse-Geisser tail probabilities and epsilon factors (e) are listed in the text.
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We also examined our data for baseline to trance changes in the dominant alpha frequency, which were found in the hyper aroused states reported by Das and Gastaut (1957) and Surwillo and Hobson (1978). Six of the seven subjects analyzed above for beta I and II had well-developed alpha trains in baseline and trance. Their data from the left occipital site (01) were low-pass filtered at 14 Hz and the mean alpha frequency in baseline and in trance for each subject was determined with signal-processing software.
For all six subjects analyzed, the dominant alpha frequency increased in frequency from baseline to trance. The mean baseline alpha frequency was 10.06 Hz (range, 9.36 Hz – 10.85 Hz) and the mean trance frequency was 10.67 Hz (range, 9.70 Hz – 11.90 Hz); (Matched-sample Mest, t = 3.47, df= 5, p = .018, two-tailed).
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