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Lucid dreaming: Correspondence between dreamed and actual events in one subject during rem sleep
Biological Psychology 18 (1984) 243-252 North-Holland
243
LUCID DREAMING: CORRESPONDENCE BETWEEN DREAMED ACTUAL EVENTS IN ONE SUBJECT DURING REM SLEEP * Peter FENWICK, Morton SCHATZMAN, Sonya STONE and Anne BAKER EEG Department, Accepted
Alan WORSLEY,
AND
Joan ADAMS,
St. Thomas’ Hospital, London SE1 7EM, UK
for publication
22 September
1983
During lucid dreaming, a subject willed movements of his fingers, toes and feet, remembered tasks, and counted sensory stimuli. Dreamed speech was related to respiration. EMG activity corresponding to dreamed actions was greater in flexor than in extensor limb muscles and was never present in axial muscles.
1. Introduction
A lucid dream is a dream during which the subject is conscious of dreaming (van Eeden, 1919; Green, 1968). Previous research has shown that during REM sleep certain subjects can signal that they are dreaming lucidly by means of volitional eye movements (recorded by electro-oculogram) and forearm muscle contractions (recorded by electromyogram) (Hearne, 1978; LaBerge, Nagel, Dement and Zarcone, 1981). If confirmed, these results suggest the possibility of a new method for examining experimentally the long-standing assumption that a dream report of a subject awakened from REM sleep is a reliable account of what the subject really dreamed. These results suggest, too, that if, while dreaming lucidly, a subject can perceive external sensory stimuli and if the subject can signal volitionally in response to those stimuli, thereby engaging in effect in two-way communication, then the ability in dreams to perceive incoming stimuli and respond to them (for example, by counting them) could be experimentally examined. Our experiments were designed to provide data relevant to these issues and to explore the relationship in lucid dreams between the dream body and the physical body.
* We thank Sylvie Campbell, Norma West and Audrey Wyer for taking the records, making the diagrams, and typing the manuscript, and Terry Hewett for constructing the dream-machine stimulator.
0301-0511/84/$3.00
0 1984, Elsevier Science Publishers
B.V. (North-Holland)
2. Method The experiments took place in the EEG laboratory at St. Thomas’ Hospital. The subject (AW) was a forty-three year old university graduate, who for years had been cultivating an ability to dream lucidly. By history and polysomnogram his sleep was normal, and he had no psychiatric or neurologic disorder, During periods when the experiments took place, instead of pursuing his usual sleep pattern, the subject slept from 3 a.m. until 7 a.m., then came to the laboratory where EEG electrodes were applied. There he slept from 10 a.m. until 12 noon, and frequently dreamed lucidly. This unusual sleep pattern suited the laboratory technicians, who preferred day-time to night-time experin~entation, and it was also intended to increase the yield of lucid dreams: having experimented on his own informally with various sleep patterns, he had gained the impression that, if he interrupted his night-time sleep after a few hours, stayed awake, and returned to sleep, the incidence of lucid dreams in the last sleep period would be particularly high. This observation requires objective confirmation. The electrodes were placed according to the lo-20 system, together with two channels for horizontal and vertical eye movements, which were recorded with AC-coupled electrodes, a submental EMG and additional channels for each particular experiment. Sleep stages were scored according to the criteria of Rechtschaffen and Kales (1968). 3. Results All experiments reported here occurred during stage REM, as shown by the absence of submental EMG, by spontaneously occurring rapid eye movements preceding an following the volitional eye movements that signalled lucidity onset, by a theta-dominant EEG, and by power spectral analysis, which for epochs immediately following lucidity-onset showed the usual REM spectral profile. In one experiment, before going to sleep in the laboratory, the subject planned to signal lucidity onset with eye movements, to dream of drawing a triangle on a blackboard with chalk held in his right hand, and to follow the chalk movements with his eyes. After waking, he related that in a dream he had become lucid and performed the tasks successfully. The vertical and horizontal eye movement channels showed the lucidity-onset signals and a series of potentials which apparently coincided with the subject’s dreaming of his eyes following his hand drawing the triangle. Our impression is that his physical eyes actually tracked the outline of the triangle; we cannot say this with complete confidence because the eye movements were recorded with AC-coupled electrodes. The right-forearm EMG showed bursts of activity apparently coinciding with the strokes of his dream hand. Thus actions in a dream produced corresponding eye movements and EMG responses.
P. Fenwick et al. / Lucid dreaming
245
In another experiment, the subject planned to dream of moving his finger smoothly from side to side and following it with his eyes to determine if he could produce slow scanning movements of his physical eyes. These eye movements are controlled by the frontal lobe eye-movement centre and are very difficult to produce in the absence of a ‘real’ stimulus. The subject succeeded, which indicates that volitional high-precision eye movements are possible during REM sleep, and that, when dream eyes follow the movements of a dream hand, the physical eyes move in the same way they would if the subject were awake and following slow to-and-fro movements of his hand. In this experiment we lost no useful information by recording with AC-coupled electrodes because, in studying slow scanning movements, we found the frequency of the movements to be within the band pass of the EEG recording system. We then studied body movements. It has been suggested that cataplexy is due to the same type of mechanism that produces loss of muscle tone in REM sleep, and there is evidence that in cataplectic attacks different muscle groups may be paralysed unequally, the jaw muscles and knee extensors being paralysed first (Guilleminault, 1976). It has been reported that in REM sleep tonic activity is decreased markedly in some muscle groups, but not in others (Jacobson, Kales, Lehmann and Hoedemaker, 1964). As well as recording tonic activity, the EMG records phasic spikes and bursts which may be below the threshold for visible displacement of a body part. We wished to see whether in lucid REM sleep the duration and amplitude of phasic spikes and bursts varied among different muscle groups. To test this, EMG electrodes were placed on the right forearm (finger flexors), right upper arm (forearm flexors) and right axial muscles (shoulder flexors). After giving pre-arranged lucitity-onset signals with his eyes, the subject, who is right-handed, dreamed several times of making movements involving these muscles. A clear hierarchy was evident; no EMG activity was ever recorded from the axial muscles, and the EMG from the forearm flexors consistently showed lower amplitude and shorter bursts than the EMG from the finger flexors. The experiment was repeated for the lower limbs with similar results. Thus in the upper and lower extremities, the motor inhibition of REM was strongest in the axial muscles and progressively weaker towards the peripheral muscles. It is interesting that the inhibition is not uniform and varies along a central-peripheral axis, rather than segmentally. It is also clear that there is a precise connection between the dream body and the physical body, since a movement of a dream limb produces EMG potentials in that limb. Additional experiments comparing EMG responses in the right arm and leg flexors and extensors suggested that flexor activity was higher than extensor activity. For instance, in experiments in which the subject dreamed of moving his right leg, we recorded four times from his right lower leg and found a total of 27 flexor and 5 extensor bursts; three times from his right thigh and found
246
P. Fenwick et 01. / Lucid dreaming
c ,
f
P. Fenwick et al. / Lucid dreaming
247
248
P. Fenwick et al. / Lucid dreumrng
31 flexor and 13 extensor bursts; and once from his right hip and found 6 flexor and 3 extensor bursts. Nearly always the flexor bursts exceeded in amplitude the extensor ones. It has been reported that during REM sleep numerous very small distal limb and digital movements occur (Dement and Kleitman, 19.57). It has been suggested that, whereas eye movements seem to be specifically related to dream imagery, body movements are not (Dement and Wolpert, 1958). However, a subsequent report indicated that the account of a subject awakened from REM sleep after exhibiting fine distal limb movements generally indicated a dream in which the same limbs moved (Grossman, Gardner and Roffwarg, 1972). In our experiments, an accelerometer to measure movement was placed on the subject’s right long finger. Before going to sleep, the subject planned to dream in a lucid dream of wiggling that finger to and fro anterodorsally five times, then four times, then three times, then twice, then once, and to remain asleep afterwards. He succeeded, and the accelerometer record displayed that his finger moved according to the planned pattern (fig. 2). A similar experiment involving the right lower extremity demonstrated that he could produce minor willed movements of his physical toes and feet, but not of his legs. Next, we studied memory and mentation during REM. The subject was connected to a device which measures lateral eye movements recorded from an electro-oculogram and delivers a shock if the amplitude of the eye movement exceeds a pre-set level. Stimulating electrodes were placed on the subject’s forearm, and one hour after he went to sleep the machine was switched on. The subject’s task was to signal lucidity onset with his eyes; to indicate with forearm muscle bursts how many shocks he intended to administer to himself; to administer them by means of eye movements; and, after administering the intended number, to indicate that number with forearm muscle bursts. He did this successfully (fig. 3), and correctly indicated that he had received three shocks. This result shows that, while dreaming, he remembered an experiment planned when he was awake, understood that the eye movements would produce shocks, and counted the shocks as he made them, counted the number of shocks he received (whether he actually perceived them or only dreamed he did) ’ and remembered the number long enough to signal that number. The conclusion is that complex cerebral activity is possible during REM sleep.
’ That
the subject
The coupling since
a shock
cumulative shocks
perceived
between might
amplitudes
were variable.
virtually receiving
the precise
the shocks
rather
the shock-producing be administered
than dreamed machine
if either
of several eye movements Under
moment
these circumstances
them is probable
and the eye movements
the amplitude was sufficiently
for these reasons: was not precise,
of one eye movement
it would have been very difficult
at which the last of a series of shocks was actually
the last of a series of shocks having the correct
or the
high; and the gaps between
total number.
to dream,
administered,
the at of
REM
Fig. 3.
EMG RTw+ FOREARM
-
WILLCOUNT 3 PAPERSPEUl=75m~c T.C. O-3!% lOO/lJv H.F. 150Hz b SK SENSllIVllY+$y/m
LAT EYE-----MOVEMENTS
P3-01s
IL-TG-,-._-.
SlJBMENlAL EMG
SHOCK
1.2
\
: = ;*,i,
3.HAVEHAD3. Wltt COUNT 2.
L
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I
I
i
I
.L,IU
AWAKE FYFSClnSFn _~
P. Fenwick et al. / Lucid dreaming
250
Ii .-. 7 .-_ -4 i
-1 T.5
!_uCL-
--
P. Fenwtck et al. / Lucid dreaming
Here is his report of that dream, which just after waking up he narrated a tape recorder.
251
into
I seem to be lying on the ground by a fence outside a building with my sleeping bag over me (in fact, he did have a sleeping bag over him). It’s raining and a bit dark. Puddles of water are about. One or two people come through a gate next to me and walk through puddles splashing water about as if I weren’t there. I expect them to ask me what I’m doing there, but they don’t. I think I can see my alarm clock, which makes me wonder whether I’m awake. However, from past experience I know that, whenever I’ve wondered whether I was awake, in the end it’s turned out that I was asleep, so I assume I must be asleep. I’m aware of the machine that’s supposed to deliver the shocks. He then dreamed of performing the planned sequence of tasks, which, as we reported above, the objective record indicated he did perform. While performing the tasks, he worried about the machine getting wet in the rain. This suggests that, while carrying out the planned experiment, he experienced the machine as part of the dream and, despite being aware that he was dreaming, he felt the rain was real enough to make the machine wet. Finally, we investigated speech during lucid dreaming. Before the subject went to sleep, he planned to count out loud in his dream and on each count to dream of moving his hand. He was successful; in his dream he counted ‘one’, ‘ two’, and so on, while dreaming of scraping the numbers with the handle of a brush on a road surface. The EMG potentials from his forearm, which coincided with his dream speech, occurred at or near the beginning of expiration, as they do normally during waking speech (speech usually occurs during expiration) - (see fig. 4). Thus dream speech appears to be linked to the expiratory phase of actual respiration. No surface EMG activity suggestive of movement in the laryngeal muscles was recorded.
4. Conclusion From our experiments we conclude that, during lucid dreams, conjugate tracking movements of the eyes and complex muscle activity in the fingers, toes and distal limbs are possible. Apparently, some skeletal muscles display EMG bursts or actual movements coincident with dreamed movements of the corresponding parts of the dream body. Apparently, too, lucid dream speech is linked to the actual respiratory cycle. The same, we suggest, may be true of non-lucid dreams, but without the conscious participation of sleeping subjects these matters are difficult to investigate.
252
P. Fenwick ef al. / Lucid dreaming
We conclude, too, that in lucid dreams remembering, thinking and counting can occur. Anecdotes which suggest that the same may be true of non-lucid dreams are unconfirmed by experimental evidence, since sleeping subjects who are not lucid cannot consciously participate concurrently in experiments. We suggest that the use of trained lucid dreamers as research subjects and experimenters opens up a new avenue for investigating events in REM sleep.
References Dement, W. and Kleitman, N. (1957). EEG and Clinical Neurophysiology, 9, 6733690. Dement, W. and Wolpert, E.A. (1958). Journal of Experimental Psychology, 55 (6) 543-553. Green, C.E. (1968). Lucid Dreams. Hamish Hamilton: London. Grossman, WI., Gardner R. and Roffwarg, H.P. (1972). Psychophysiology, 9, 1188119. Guilleminault, C. (1976). Narcolepsy. I. Guilleminault, C., Dement. W.C. and Passonant, P. (Eds.). Spectrum Publications Inc. p. 125. Hearne, K.M.T. (1978). Lucid dreams: An electrophysiological and psychological study. Ph.D. Thesis. Liverpool University. Jacobson, A., Kales A., Lehmann, D. and Hoedemaker, F.S. (1964). Experimental Neurology, 10, 418-424. LaBerge, S.P., Nagel, L.E., Dement, W.C. and Zarcone, V.P. (1981) Perceptual and Motor Skills, 52, 727-732. Rechtschaffen, A. and Kales, A. (Eds.). (1968). A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. U.C.L.A. Brain Information Service, Brain Research Institute: Los Angeles. van Eeden, F. (1913). Proceedings of The Society for Psychical Research, 26, 431-461.
243
LUCID DREAMING: CORRESPONDENCE BETWEEN DREAMED ACTUAL EVENTS IN ONE SUBJECT DURING REM SLEEP * Peter FENWICK, Morton SCHATZMAN, Sonya STONE and Anne BAKER EEG Department, Accepted
Alan WORSLEY,
AND
Joan ADAMS,
St. Thomas’ Hospital, London SE1 7EM, UK
for publication
22 September
1983
During lucid dreaming, a subject willed movements of his fingers, toes and feet, remembered tasks, and counted sensory stimuli. Dreamed speech was related to respiration. EMG activity corresponding to dreamed actions was greater in flexor than in extensor limb muscles and was never present in axial muscles.
1. Introduction
A lucid dream is a dream during which the subject is conscious of dreaming (van Eeden, 1919; Green, 1968). Previous research has shown that during REM sleep certain subjects can signal that they are dreaming lucidly by means of volitional eye movements (recorded by electro-oculogram) and forearm muscle contractions (recorded by electromyogram) (Hearne, 1978; LaBerge, Nagel, Dement and Zarcone, 1981). If confirmed, these results suggest the possibility of a new method for examining experimentally the long-standing assumption that a dream report of a subject awakened from REM sleep is a reliable account of what the subject really dreamed. These results suggest, too, that if, while dreaming lucidly, a subject can perceive external sensory stimuli and if the subject can signal volitionally in response to those stimuli, thereby engaging in effect in two-way communication, then the ability in dreams to perceive incoming stimuli and respond to them (for example, by counting them) could be experimentally examined. Our experiments were designed to provide data relevant to these issues and to explore the relationship in lucid dreams between the dream body and the physical body.
* We thank Sylvie Campbell, Norma West and Audrey Wyer for taking the records, making the diagrams, and typing the manuscript, and Terry Hewett for constructing the dream-machine stimulator.
0301-0511/84/$3.00
0 1984, Elsevier Science Publishers
B.V. (North-Holland)
2. Method The experiments took place in the EEG laboratory at St. Thomas’ Hospital. The subject (AW) was a forty-three year old university graduate, who for years had been cultivating an ability to dream lucidly. By history and polysomnogram his sleep was normal, and he had no psychiatric or neurologic disorder, During periods when the experiments took place, instead of pursuing his usual sleep pattern, the subject slept from 3 a.m. until 7 a.m., then came to the laboratory where EEG electrodes were applied. There he slept from 10 a.m. until 12 noon, and frequently dreamed lucidly. This unusual sleep pattern suited the laboratory technicians, who preferred day-time to night-time experin~entation, and it was also intended to increase the yield of lucid dreams: having experimented on his own informally with various sleep patterns, he had gained the impression that, if he interrupted his night-time sleep after a few hours, stayed awake, and returned to sleep, the incidence of lucid dreams in the last sleep period would be particularly high. This observation requires objective confirmation. The electrodes were placed according to the lo-20 system, together with two channels for horizontal and vertical eye movements, which were recorded with AC-coupled electrodes, a submental EMG and additional channels for each particular experiment. Sleep stages were scored according to the criteria of Rechtschaffen and Kales (1968). 3. Results All experiments reported here occurred during stage REM, as shown by the absence of submental EMG, by spontaneously occurring rapid eye movements preceding an following the volitional eye movements that signalled lucidity onset, by a theta-dominant EEG, and by power spectral analysis, which for epochs immediately following lucidity-onset showed the usual REM spectral profile. In one experiment, before going to sleep in the laboratory, the subject planned to signal lucidity onset with eye movements, to dream of drawing a triangle on a blackboard with chalk held in his right hand, and to follow the chalk movements with his eyes. After waking, he related that in a dream he had become lucid and performed the tasks successfully. The vertical and horizontal eye movement channels showed the lucidity-onset signals and a series of potentials which apparently coincided with the subject’s dreaming of his eyes following his hand drawing the triangle. Our impression is that his physical eyes actually tracked the outline of the triangle; we cannot say this with complete confidence because the eye movements were recorded with AC-coupled electrodes. The right-forearm EMG showed bursts of activity apparently coinciding with the strokes of his dream hand. Thus actions in a dream produced corresponding eye movements and EMG responses.
P. Fenwick et al. / Lucid dreaming
245
In another experiment, the subject planned to dream of moving his finger smoothly from side to side and following it with his eyes to determine if he could produce slow scanning movements of his physical eyes. These eye movements are controlled by the frontal lobe eye-movement centre and are very difficult to produce in the absence of a ‘real’ stimulus. The subject succeeded, which indicates that volitional high-precision eye movements are possible during REM sleep, and that, when dream eyes follow the movements of a dream hand, the physical eyes move in the same way they would if the subject were awake and following slow to-and-fro movements of his hand. In this experiment we lost no useful information by recording with AC-coupled electrodes because, in studying slow scanning movements, we found the frequency of the movements to be within the band pass of the EEG recording system. We then studied body movements. It has been suggested that cataplexy is due to the same type of mechanism that produces loss of muscle tone in REM sleep, and there is evidence that in cataplectic attacks different muscle groups may be paralysed unequally, the jaw muscles and knee extensors being paralysed first (Guilleminault, 1976). It has been reported that in REM sleep tonic activity is decreased markedly in some muscle groups, but not in others (Jacobson, Kales, Lehmann and Hoedemaker, 1964). As well as recording tonic activity, the EMG records phasic spikes and bursts which may be below the threshold for visible displacement of a body part. We wished to see whether in lucid REM sleep the duration and amplitude of phasic spikes and bursts varied among different muscle groups. To test this, EMG electrodes were placed on the right forearm (finger flexors), right upper arm (forearm flexors) and right axial muscles (shoulder flexors). After giving pre-arranged lucitity-onset signals with his eyes, the subject, who is right-handed, dreamed several times of making movements involving these muscles. A clear hierarchy was evident; no EMG activity was ever recorded from the axial muscles, and the EMG from the forearm flexors consistently showed lower amplitude and shorter bursts than the EMG from the finger flexors. The experiment was repeated for the lower limbs with similar results. Thus in the upper and lower extremities, the motor inhibition of REM was strongest in the axial muscles and progressively weaker towards the peripheral muscles. It is interesting that the inhibition is not uniform and varies along a central-peripheral axis, rather than segmentally. It is also clear that there is a precise connection between the dream body and the physical body, since a movement of a dream limb produces EMG potentials in that limb. Additional experiments comparing EMG responses in the right arm and leg flexors and extensors suggested that flexor activity was higher than extensor activity. For instance, in experiments in which the subject dreamed of moving his right leg, we recorded four times from his right lower leg and found a total of 27 flexor and 5 extensor bursts; three times from his right thigh and found
246
P. Fenwick et 01. / Lucid dreaming
c ,
f
P. Fenwick et al. / Lucid dreaming
247
248
P. Fenwick et al. / Lucid dreumrng
31 flexor and 13 extensor bursts; and once from his right hip and found 6 flexor and 3 extensor bursts. Nearly always the flexor bursts exceeded in amplitude the extensor ones. It has been reported that during REM sleep numerous very small distal limb and digital movements occur (Dement and Kleitman, 19.57). It has been suggested that, whereas eye movements seem to be specifically related to dream imagery, body movements are not (Dement and Wolpert, 1958). However, a subsequent report indicated that the account of a subject awakened from REM sleep after exhibiting fine distal limb movements generally indicated a dream in which the same limbs moved (Grossman, Gardner and Roffwarg, 1972). In our experiments, an accelerometer to measure movement was placed on the subject’s right long finger. Before going to sleep, the subject planned to dream in a lucid dream of wiggling that finger to and fro anterodorsally five times, then four times, then three times, then twice, then once, and to remain asleep afterwards. He succeeded, and the accelerometer record displayed that his finger moved according to the planned pattern (fig. 2). A similar experiment involving the right lower extremity demonstrated that he could produce minor willed movements of his physical toes and feet, but not of his legs. Next, we studied memory and mentation during REM. The subject was connected to a device which measures lateral eye movements recorded from an electro-oculogram and delivers a shock if the amplitude of the eye movement exceeds a pre-set level. Stimulating electrodes were placed on the subject’s forearm, and one hour after he went to sleep the machine was switched on. The subject’s task was to signal lucidity onset with his eyes; to indicate with forearm muscle bursts how many shocks he intended to administer to himself; to administer them by means of eye movements; and, after administering the intended number, to indicate that number with forearm muscle bursts. He did this successfully (fig. 3), and correctly indicated that he had received three shocks. This result shows that, while dreaming, he remembered an experiment planned when he was awake, understood that the eye movements would produce shocks, and counted the shocks as he made them, counted the number of shocks he received (whether he actually perceived them or only dreamed he did) ’ and remembered the number long enough to signal that number. The conclusion is that complex cerebral activity is possible during REM sleep.
’ That
the subject
The coupling since
a shock
cumulative shocks
perceived
between might
amplitudes
were variable.
virtually receiving
the precise
the shocks
rather
the shock-producing be administered
than dreamed machine
if either
of several eye movements Under
moment
these circumstances
them is probable
and the eye movements
the amplitude was sufficiently
for these reasons: was not precise,
of one eye movement
it would have been very difficult
at which the last of a series of shocks was actually
the last of a series of shocks having the correct
or the
high; and the gaps between
total number.
to dream,
administered,
the at of
REM
Fig. 3.
EMG RTw+ FOREARM
-
WILLCOUNT 3 PAPERSPEUl=75m~c T.C. O-3!% lOO/lJv H.F. 150Hz b SK SENSllIVllY+$y/m
LAT EYE-----MOVEMENTS
P3-01s
IL-TG-,-._-.
SlJBMENlAL EMG
SHOCK
1.2
\
: = ;*,i,
3.HAVEHAD3. Wltt COUNT 2.
L
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I
I
i
I
.L,IU
AWAKE FYFSClnSFn _~
P. Fenwick et al. / Lucid dreaming
250
Ii .-. 7 .-_ -4 i
-1 T.5
!_uCL-
--
P. Fenwtck et al. / Lucid dreaming
Here is his report of that dream, which just after waking up he narrated a tape recorder.
251
into
I seem to be lying on the ground by a fence outside a building with my sleeping bag over me (in fact, he did have a sleeping bag over him). It’s raining and a bit dark. Puddles of water are about. One or two people come through a gate next to me and walk through puddles splashing water about as if I weren’t there. I expect them to ask me what I’m doing there, but they don’t. I think I can see my alarm clock, which makes me wonder whether I’m awake. However, from past experience I know that, whenever I’ve wondered whether I was awake, in the end it’s turned out that I was asleep, so I assume I must be asleep. I’m aware of the machine that’s supposed to deliver the shocks. He then dreamed of performing the planned sequence of tasks, which, as we reported above, the objective record indicated he did perform. While performing the tasks, he worried about the machine getting wet in the rain. This suggests that, while carrying out the planned experiment, he experienced the machine as part of the dream and, despite being aware that he was dreaming, he felt the rain was real enough to make the machine wet. Finally, we investigated speech during lucid dreaming. Before the subject went to sleep, he planned to count out loud in his dream and on each count to dream of moving his hand. He was successful; in his dream he counted ‘one’, ‘ two’, and so on, while dreaming of scraping the numbers with the handle of a brush on a road surface. The EMG potentials from his forearm, which coincided with his dream speech, occurred at or near the beginning of expiration, as they do normally during waking speech (speech usually occurs during expiration) - (see fig. 4). Thus dream speech appears to be linked to the expiratory phase of actual respiration. No surface EMG activity suggestive of movement in the laryngeal muscles was recorded.
4. Conclusion From our experiments we conclude that, during lucid dreams, conjugate tracking movements of the eyes and complex muscle activity in the fingers, toes and distal limbs are possible. Apparently, some skeletal muscles display EMG bursts or actual movements coincident with dreamed movements of the corresponding parts of the dream body. Apparently, too, lucid dream speech is linked to the actual respiratory cycle. The same, we suggest, may be true of non-lucid dreams, but without the conscious participation of sleeping subjects these matters are difficult to investigate.
252
P. Fenwick ef al. / Lucid dreaming
We conclude, too, that in lucid dreams remembering, thinking and counting can occur. Anecdotes which suggest that the same may be true of non-lucid dreams are unconfirmed by experimental evidence, since sleeping subjects who are not lucid cannot consciously participate concurrently in experiments. We suggest that the use of trained lucid dreamers as research subjects and experimenters opens up a new avenue for investigating events in REM sleep.
References Dement, W. and Kleitman, N. (1957). EEG and Clinical Neurophysiology, 9, 6733690. Dement, W. and Wolpert, E.A. (1958). Journal of Experimental Psychology, 55 (6) 543-553. Green, C.E. (1968). Lucid Dreams. Hamish Hamilton: London. Grossman, WI., Gardner R. and Roffwarg, H.P. (1972). Psychophysiology, 9, 1188119. Guilleminault, C. (1976). Narcolepsy. I. Guilleminault, C., Dement. W.C. and Passonant, P. (Eds.). Spectrum Publications Inc. p. 125. Hearne, K.M.T. (1978). Lucid dreams: An electrophysiological and psychological study. Ph.D. Thesis. Liverpool University. Jacobson, A., Kales A., Lehmann, D. and Hoedemaker, F.S. (1964). Experimental Neurology, 10, 418-424. LaBerge, S.P., Nagel, L.E., Dement, W.C. and Zarcone, V.P. (1981) Perceptual and Motor Skills, 52, 727-732. Rechtschaffen, A. and Kales, A. (Eds.). (1968). A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects. U.C.L.A. Brain Information Service, Brain Research Institute: Los Angeles. van Eeden, F. (1913). Proceedings of The Society for Psychical Research, 26, 431-461.