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III. State of sleep characterized by fast cortical activity paradoxical sleep
E. Relationship With Oneiric Activity in Man
The assimilation of the paradoxical phase of sleep in the cat with the
oneiric activity phase (REM phase) in man has raised many arguments. Today,
if we compare the paradoxical phase of sleep in the cat and the REM phase
in normal man (24, 121,
126, 127,
168, 233,
249, 257,
377) or in patients suffering
from various cerebral lesions (255,
353), there is no doubt about
the similarity of the phenomena (241,
249, 408)
(Table 2) and that there is "a need" (first elicited in man)
"for oneiric activity" appearing during selective deprivation
experiments (123, 125).
The demonstration of the relationship between oneiric activity and REM
sleep in man allows us to speculate that mechanisms and structures, progressively
elicited in the cat during PS, will enable us to understand eventually
the causes and functions of the oneiric state. Moreover, subjective data
given by subjects awakened when dreaming, immediately after REM, seem
to reveal a close relationship between the direction of ocular movements
and the oneiric scenery ( 124,
377) . It then appears possible
that postsynaptic geniculate and occipItal. events originating in the pons
(described in the cat) may be responsible for oneiric imagery in man.
Numerous questions are still to be settled before explaining the relationship
of REM to this imagery. As a matter of fact, as in the cat, rapid eye
movements in man during sleep have patterns and speeds different from
those of visual observation, but resembling those of ocular movements
during attempts to remember events (228);
on the other hand, PS ocular movements persist in subjects suffering from
a decortication syndrome, unable to have ocular movements during wakefulness
(249, 255).
Moreover, REM occur during sleep in newborn infants (376)
and in blind-born adults (43, 345),
who cannot have visual imagery during dreaming. If phasic electrical and
oculomotor phenomena both appear to be triggered from the pontine area,
the precise determination of the temporal relationship existing between
ponto-occipItal. spikes and REM is essential in order to understand the
integrating mechanisms responsible for oneiric imagery.
TABLE 2. Similarities between paradoxical sleep in the cat and
REM sleep in humans
EEG |
Cat (adult) |
Man (Adult) |
Cortical activity |
Fast, low voltage (similar to arousal) |
Scalp recording: low-voltage, 6-8 cycles/sec in occipItal.
areas |
Evoked responses by visual or auditory stimuli |
Decreased |
Average response decreased |
Physiological behavior |
Cat (adult) |
Man (adult) |
EMG Activity |
EMG Activity of the neck totally decreased |
Subhyoidian muscle activity totally decreased |
Monosynaptic reflexes |
Decreased or abolished |
Decreased or abolished (H-reflexes) |
Ocular movements |
Present |
Present |
Pupillary diameter |
Myosis |
|
Heart rate |
Mostly decreased, irregularity |
Mostly increased, irregularity |
Blood pressure |
Decreased |
Increased but different method |
Respiration |
Irregularity |
Irregularity |
GSR |
Decreased |
Decreased |
|
Cat (adult) |
Man (adult) |
Functionnal aspects |
- |
- |
Arousal threshold |
- |
- |
Auditory stimulation |
Increased |
Superior or equal to stage III equal to stage IV |
Periodicity |
20-28 % of total sleep time, always follows slow sleep |
20-25 % of total sleep time, always follows slow sleep
|
Result of selective deprivation |
Increased during recovery |
Increased during recovery |
Structural aspects |
Persist after decortication Suppressed by pontine lesions |
Persist in case of decortication Suppressed by brain-stem
lesion involving the pons |
Ontogenesis |
Present immediately after birth, may directly follow
waking |
Present immediately after birth, may directly follow
waking |
Subjective experience |
Unknown |
Dreaming |
From Dement, W. C., and M. Jouvet. General discussion. In Aspects
anatomo-fonctionnels de la physiologie du sommeil, edited by M. Jouvet.
Paris Centre Natl. Rech. Sci., 1965.
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