Basic HTML Version
ELE~OPHYSIOLOGICAL
THEORY
4!5
the maintenance of bioelectrical arousal
in
brain
&.em
reticular forma-
the inhibition of “behavioral arousal”;
the exclusion of the specific afferent system from participation in
total-stimulus-and-response
through the central integrating
sys-
tem;
this
exclusion being effected by
the inhibition of the passage of information from parasensory cortical
areas and from orbibfrontal , anterior cingulate, and anterior
temporal cortex
into
the reticular formation
of
mesencephalon
and
diencephalon.
Hypnosis
is
thus held to be caused by
a
complex balance of bio-
electrical mechanisms,which will
be
discussed
in
detail
in
the following
section.
iMechanisms
Bioelectncal arousal.
The typical
waking
pattern of the electroen-
cephalogram, known to be present under hypnosis, was shown by
Moruzei and Magoun
to
depend upon the activation of an ascending
reticular formation medially placed
in
the brain stem. This pathway
is functionally and anatomically differentiated from the ascending
sensory and somatic pathways (Magoun,
1952)
;
with mesencephalic
section of the sensory and somatic afferent pathways an animal may
wake and sleep, and may be
aroused
by
peripheral stimulation. Such
a
coincidence
of
reticular activation with damping
of
sensory-afferent
activity would appear
to
be the central condition of hypnosis, where it
is
produced not by surgical means but by
a
manipulation of cephalic
control mechanisms. Electrophysiologically, hypnosis
is
to be
distin-
guished from normal deep by the fact that bioelectrical arousal is re-
tained under hypnosis;
so
long
as
the waking rhythms which facilitate
cortical elaboration and response are active, the subject
will
react,
in
quasi-somnambulistic fashion, to suggestion; normal sleep supervenes
upon hypnosis whenever these rhythms cease activity.
It
would appear that the preservation of waking electrocortical ac-
tivity through the sleeplike
state
of
hypnosis
is
achieved empirically
by the hypnotic induction techniques
of
“fixation.”
Various
in
practice,
these techniques,
in
the analysis of Kubie
and
Margolin, have the com-
mon element
of
attentiveness
to
monotonous, repetitive, and
often
rhyth-
mical stimuli
in a
single
sensory modality. The
state
achieved
can
be
described
as
counter-noml
only
if
it
can be assumed,
as
seems
probable
from electroencephalographic
studies,
that
in
the
normal
process
of
falling asleep central reticular activity ceases in advance of peripheral
afferent
activity.
tion and cortex;
Downloaded by [University of Macedonia] at 02:09 29 March 2012