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52
DONALD
R.
ROBERTS
stimuli,
and
facilitated by immobilization; having the effect of
altering field potentials or slowing the pace of impulse activity;
(b) localized “suppression” in the cortical regions projecting into the
brain stem reticular formation, attenuating these projections by
inhibiting recruitment or other reinforcement between the specific
and diffuse projective activity.
Discussion
and Interpretation
The role in hypnosis of the diffuse projection of the thalamic reticular
formation is uncertain. The degree to which the content of impulses in
this projection is differentiated in modality (sensory, somesthetic, etc.)
has not been clearly established; hence
it
cannot be safely posited that
the diffuseprojection could serve as the vehicle of perception in hypnosis.
The pronounced
loss
of sensory and sensorimotor definition which often
occurs with hypnosis, however (see Weitzenhoffer, p.
119)
,
is
consistent
with a hypothesis of perception through
a
secondary system.
On
the
other hand, the inhibition of the diffuse projection could in all proba-
bility effect the hypnotic dissociation; Dynes’ tracing of
a
subject going
into instantaneous trance gives an indication (which would require ex-
perimental confirmation) of a smoothing of minor activity such
as
would
occur with
a
suppression of impulse activity in the specific or diffuse
projections. Although the precise modes of cortical interaction of the
specific and diffuseprojections have not as yet been fully defined,
it
is
difficult to reject the conclusion,
on
the present status of research, that
the entry of data of sensory origin into central consciousness is con-
ditioned by this interaction; and the substance of the present theory is
that hypnosis, conversely, is conditioned by the inhibition of this inter-
action.
The puzzling lability of hypnotic and hypnoidal behavior points to-
ward
an electrodynamic event in the brain, rather than
an
event with
a
mechanical or organic aetiology. The precise mechanisms involved in
hypnosis will in all probability be finally defined
in
terms of concepts
such
as
periodicity, synchronicity, synaptic potential, volume of rhythm
potentials,
and
other parameters
of
electrical activity.
It
is becoming
increasingly apparent that the
gross
electrical activity of the brain may
well be governed by simple quantitative factors.
Hypnosis is then to be regarded
as
an electrical rather than
a
chemical
event, with this exception: that certain
states
of trance, requiring up to
15
minutes for induction (Ravitz,
1961)
are suggestive of the interven-
tion of some
sort
of “suppression,”
a
process which
may
be chemically
mediated (Grafstein,
1956).
Any form of suppression or “spreading de-
pression” allied
to
hypnosis would appear
to
have two conditions:
non-
interference with the waking rhythms, and inhibition of impulse ac-
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