PSYCHEDELICS - Sciencemadness.org

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____________________________________________________ Psychedelics
to point out that these brain waves vary with the functional
state of the organism, and, of less importance here, that they
signal, by abnormal wave forms and "spikes," pathological
processes in the brain. As to the former aspect, it was recognized
quite early in the development of the electroencephalographic
technique that fundamental changes occur in the
appearance of the EEG, derived from the scalp in man and
from the surface of the brain in animals, as the subjects shift
from the aroused attentive state to quietly resting waking, to
drowsiness, and to light and then deep sleep. In the aroused
state, the EEG is characterized by an irregular low-voltage
pattern exhibiting frequencies of about fifteen to thirty cycles
per second, the so-called beta waves. In resting waking there
are, particularly in the posterior part of the brain, the typical
alpha waves, i.e., rather regular oscillations of about eight to
twelve per second (of somewhat lower frequencies in the
cat). During the drowsy, or "floating," state, the alphas
gradually disappear and are replaced again by a beta pattern.
With the onset of actual sleep, the EEG is characterized
first by the occurrence of bursts of ten-to-fourteen-per-second
waves that wax and wane so as to produce a spindlelike
envelope; hence we refer to these as sleep spindles. With the
shift to deeper states of sleep, high-voltage, very slow waves
(delta waves, one to three per second) dominate the picture.
More recently it has been found that subjects can be sound
asleep and still show at times episodes of arousal patterns in
the EEG (i.e., low-voltage beta waves); these episodes are
accompanied by rapid eye movements (REMs). When
human subjects are awakened during these REM periods,
they almost invariably report that they have been dreaming,
whereas they do not do so when awakened from a slow sleep
episode. It is for this reason that we think today that during
these REM periods, or periods of "paradoxical" or "activated"
sleep, we dream. These REM episodes occur in man about
every ninety minutes, in the cat about every thirty minutes.
Figure 1 shows some typical records obtained from a "chronic"
freely moving cat. With the help of such tracings, together
with continuous observation, the actual level of "vigilance"
can be diagnosed with a high degree of reliability. The experiments
discussed below are based on such techniques.