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[The link bar feature is not available in this web]What is HEG (HEMOENCEPHALOGRAPY)?
HEG (hemoencephalography) is the study of blood flow in the brain. More
specifically, it is the study of voluntarily controlled blood flow or
oxygenation in specifically chosen brain modules.
Many major functions occupy clearly defined volumes. Some of these are well
known. There is a module devoted to making sense of visual objects. The face
fusiform area recognizes faces. It is located at the lower (inferior) part of
the right temporal lobe over the right ear. The module used for working
memory is usually located just above the left eye in the frontal (anterior)
area of the left frontal lobe. There are obviously many more. Not all people
have identical areas devoted to a particular function. Any particular
function may call upon the primary module and several helpful modules to
complete an operation. Location of these modules is a study in itself.
Blood brings oxygen and the basic nutrient, glucose, at life sustaining
levels to all parts of the brain. Our brains have an amazing ability to
supply extra blood preferentially to those modules in current use. Since even
in repose the brain uses 1/5 of all the energy used in the body. It produces
temperature rises in the used (venous) blood. If we used the entire brain at
one time it would overheat and be severely damaged. The flow of blood cools
the brain and prevents overheating.
Active modules are marked by high oxygen density and higher than normal
temperature. Simple measurements can locate active modules. Note here that we
have no sense that tells us where an active module is located. For example
when we stand, activity occurs in the motor strip across the top of the head.
We have no sensation with information about the exact location of that active
bit of tissue.
From infancy on, we have learned to use specific bits of brain tissue for
accomplishing familiar tasks. We carry out that the same learning process for
anything new. We may want to do something we see others do or we try to do
something that seems possible. Initially we accomplished it by trial and error.
In trying, we find some modicum of success. We are encouraged so we try again
and again. We improve as we go.
Fortunately, we can use a sophisticated infrared thermometer, passive
infrared HEG (pirHEG), developed by my esteemed colleague, Jeffrey A. Carmen,
or an optical probe, near infrared HEG (nirHEG) developed by the originator
of HEG Hershel Toomim, that shines light through the skin and skull to assess
the color of brain tissue. Oxygenated arterial blood is red, deoxygenated
venous blood is blue. Increased demand for nutrition results in faster blood
flow and redder blood in the tissues.
With these facts in mind we have an outstanding method, HEG, of doing
Neurofeedback.
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