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Journal of Neurotherapy
Volume 3, Number 4 - Fall &
Winter 1999
Intentional Control of Regional
Cerebral Blood Flow with the Thinking Cap.
Hershel Toomim and Antoine Remond.
Introduction to Voluntary Cerebral
Blood Flow: Increased blood flow to active brain areas is
demonstrated in many PET, fMRI, and SPECT studies. Many such studies
have shown abnormal regional cerebral blood flow (rCBF) in brain
disorders such as Schizophrenia, Alzheimer’s, Parkinson’s,
Attention Deficit Disorder, substance abuse, depression, dementia
and others. Blood supplies oxygen and glucose to support energy
requirements of brain metabolism. The Delta and Theta activity in
the EEG has also been shown to correlate highly to regional cerebral
blood flow (rCBF) (2,3,11,16). Studies of brain activities using
these scanning instruments show increased blood flow and metabolism
in brain areas activated by the experimental subject during selected
brain functions. The subject has no awareness of the brain locale
activated. The choice of active brain locales is entirely
unconscious. Increased vascularity developed in enhanced
environments has been demonstrated in rodents (M. Rosensweig, and
Diamond 1962) but has not been shown in humans.
Purpose: This study examines
intentional increase of blood perfusion in a chosen brain area when
the subject is suitably informed of the rCBF of that brain region.
The study evaluates increased vascularity at the chosen sites due to
exercise.
Method: The interior of the
skull is not dark.. Incident light on the head penetrates the
translucent scalp and skull. This fact has been amply demonstrated
many studies since 1980.A spectrophotometer depending on the
translucent characteristics of the scalp and skull was used to
examine the oxygenation of capillary beds in cerebral cortex
(6,7,8,9,10,13). Dual light sources , red and infrared, in contact
with the scalp provided cortical illumination.. The instrument
readings are minimally affected by many inter subject variations
such as intervening sinus volumes or cerebral spinal fluid filled
spaces. A ratio computation reduces the effect of variation of
incident light intensity and light absorption by the intervening
tissue volume This ratio approximates the ratio of oxygenated to
deoxygenated cortical blood. Arteries form a small proportion of the
tissue volume illuminated compared to the capillaries. The micro
circulation, is the most likely source measured. Pre-Tests:
Voluntary control of blood flow at the illuminated position was
discovered while the instrument was under development. An initial
experiment to determine the effect of intentional increase of
oxygenation was undertaken with 40 volunteers. Most subjects found
intense concentration on the task increased the reading of the
instrument placed over the left prefrontal cortex at Fp1.
Concentration greatly facilitated a rise in indicated oxygenation..
It was generally observed that learning to manipulate the indication
at Fp1 required less than 3 minutes with suitable coaching. It was
often reported that this form of brain exercise was intense, tiring,
and self limiting. It could be tolerated for a only a limited time
before rest was required. Most subjects reported a somewhat awakened
state after a 10 minute exercise period. Further experimentation
illustrated the completely unconscious character of the movement of
blood to the feedback site. Figure 1 shows an experiment using blood
flow instruments at different brain sites Cz, and Fp1. Audio
feedback was shifted from Cz to Fpz. Blood flow followed the site
from which feedback arose. The subject was unaware of the feedback
source.
Subjects: A group of 4
subjects presenting with various mental difficulties was selected
for intensive training. Two were severely depressed, another was
reported by T.O.V.A. to be ADD and the 4th with a working memory
defect was unable to read comfortably. Figure 2 shows growth in
perfusion for the 4 subjects resulting from brain exercise.
Results: The graph reflects
blood perfusion at the beginning of each session. The changes
occurred in the inter-session interval when the subjects were
engaged in ordinary daily activities. This suggests a growth effect
due to the exercise of the preceding session. The correlation
coefficient, 0.902 for the 4 subjects’ data shown by Figure 2, is
demonstrates that rCBF can be intentionally controlled by a subject
when given suitable current information. The Pearson rho correlation
coefficient (r=.902, p< .05), illustrates the significant
goodness of fit of the straight line to the experimental data. This
strongly suggests growth of the micro circulation between sessions
and may account for a major part of mental improvements gained with
all types of neurofeedback.
Discussion: The ratio of
within session maximum to minimum blood flow, calculated for each
session shows little gain after the first 2 or 3 sessions. Most of
the required learning is easy and occurs in the first session with
smaller improvements in later sessions. The data support the growth
findings of Rosensweig and Diamond, experience modifies the
physiology of the brain, and is now shown to be likely in human
brains. Effect of Scalp Blood Flow: The right and left anterior
temporal arteries supply the major portion of forehead skin and
muscles (Grays Anatomy p 495). Variation of the oxygen content of
these arteries and the tissues they supply has a negligible effect
on instrument readings. With the instrument mounted at Fp1,
occlusion of the anterior temporal arteries at the level of the
auditory meatus, which supplies blood to the forehead area, reduces
readings by less than 5%.. Perfusion of the scalp is thus shown to
have a very small effect on the readings. Now that one can direct
blood to deficient cortical areas a new dimension to brain therapies
has been added. One can speculate that there is therapeutic value in
directed voluntary control of rCBF to specific brain sites. This
remains to be validated and is being actively pursued. Some
therapeutic results have accumulated to date: These are elucidated
in follow on reports.
Key Words:
hemoencephalography, infrared, brain blood flow, spectrophotometry.
(Contact Hershel
Toomim, Sci.D., Biocomp Research Institute)
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