| |
Abstract:
Abstract: The neural correlates of hypnosis-induced increases
in relaxation and mental absorption were investigated using
positron emission tomography. Regional cerebral blood flow (rCBF)
measures and ratings of relaxation and absorption were obtained
from ten subjects in states of normal wakefulness (n = 4) and
hypnosis (n = 4), during either neutral or painfully hot
stimulation of the non-dominant left hand. Regression analyses
evaluated the relationship between rCBF and ratings, after removing
subject- and stimulation-related variance (ANCOVA). Directed
searches of brain stem rCBF changes revealed a negative correlation
with relaxation (t=-2.67) and a positive correlation with
absorption after removing relaxation-related variance (t=2.78;
ANCOVA). The correlation with relaxation was positive in bilateral
pre-central gyri (t>4.20), and negative in the right
parietal lobule, and bilateral temporal cortices (t<-4.20).
The correlation with absorption was positive in the thalamus, right
inferior parietal lobule and the bilateral insular/ventrolateral,
medial (including the anterior cingulate), and right prefrontal
cortices (t>4.20), and negative in the bilateral occipital and
parietal cortices (t<-4.20). A co-activation analysis confirmed
the correlation between absorption-related changes and thalamic
rCBF (brain stem t=2.86; cortical sites t's>3.70). This pattern
of rCBF changes associated with relaxation and absorption is
consistent with the participation of brainstem-thalamo-cortical
arousal and attention networks in the production of hypnotic
states.
|
