Consciousness

Chapter

Thirteen

Altered states of consciousness

Content of consciousness (awareness)

REM

sleep

Deep sleep

Light sleep

General

anesthesia

Coma

Drowsiness

Conscious

wakefulness

Sleepwalking

Complex partial

and absence seizures

Vegetative state

Level of consciousness (wakefulness)

FIGURE 13.4 • Oversimplified illustration of the two major components of consciousness: the level of consciousness (i.e.
wakefulness or arousal) and the content of consciousness (i.e. awareness or experience). In normal physiological
states (blue) level and content are positively correlated (with the exception of dream activity during REM sleep).
Patients in pathological or pharmacological coma (that is, general anaesthesia) are unconscious because they
cannot be awakened (pink). Dissociated states of consciousness (i.e. patients being seemingly awake but
lacking any behavioural evidence of ‘voluntary’ or ‘willed’ behaviour), such as the vegetative state or much more
transient equivalents such as absence and complex partial seizures and sleepwalking (purple), offer a unique
opportunity to study the neural correlates of awareness (Laureys, 2005, p. 556).

FIGURE 13.5 • Hobson’s AIM model describes ‘brain-mind space’ using three dimensions: A for activation energy (low to high),
I for information source (internal to external), and M for mode (cholinergic to aminergic). States of consciousness
can be positioned in the space using data from behavioural and physiological studies. (See Figure 15.3 for a
more detailed version of the model.)

experience (bliss, contact with a higher force), nirvana (absence of thought, total
absorption), and mental and bodily relaxation (reduction of tension) (Ott, 2001).
Other maps made by spiritual practitioners range from one-dimensional evo-
lutionary types (Chapter  10) to more complex spaces including hard-to-define
concepts like the cosmos, ego, faith, karma, energy, and the unconscious.