We hoped that medical literature would  more or less agree on an accepted hypothesis about the cause of Central Pain, but the experts continue to disagree. This should not be too surprising to anyone who is familiar with brain science since:

• Relatively speaking, almost nothing is known about the brain.
• With the existence of man-made computers, researchers are aware that their simplistic views about pain (and the brain itself, for that matter) are nonsensical in light of the very complex mechanisms needed to run computers that are insignificant in complexity compared to the human brain.
• Nature's systems for feedback are incredibly elaborate, and control and the brain are its most complicated accomplishments.
• Since we know little about the brain, we try to fit virtually every phenomenon observed in the brain into our limited realm of knowledge about the brain. What we already understand is incredibly complex, but we have not yet viewed the whole tip of the iceberg. For example plasticity, the brain's ability to shift processes to other anatomical areas of the brain when injury to a part of the body or a part of the brain occurs, is now an obligatory term when discussing any brain function. It doesn't explain anything but it creates the illusion that we understand a process which is completely mystifying.

Other terms of importance in studying the brain and how it reacts to pain are;

• Cholinergic: Mediated by acetyl-choline.
• Glutamatergic: Mediated by glutamate, a chemical which along with NMDA, or N-methyl-D-aspartate, is often linked to excitatory activities in the brain.
• "GABA-ergic": Mediated by gamma amino butyric acid, a chemical often involved in inhibitory functions of the brain.

It is important to understand two aspects of the brain, synapses and algorithms.

Synapses are connections or junctions between different nerve cells. They are delicate, and just as pointing a camera lens at the sun can destroy the film, putting too much excitatory chemical in the synaptic junction may damage a synapse or even kill the cell. You may refer to the Oct. 10, 1997 issue of Science for three good articles explaining how the cells responsible for at least some of Central Pain, such as the allodynia, can be killed by combining a poison with a chemical which is taken in by those cells. Just how those cells cause Central Pain is a mystery, In some fashion, they appear to be releasing the wrong chemicals due to some sort of nerve injury. Thanks go to Mantyh and Malmberg for doing the research to identify the cells responsible for allodynia. It is the first big breakthrough since mankind began to have neuropathic pain. They deserve the Nobel prize, but sadly it is likely that they will continue in their work in relative obscurity since often pain falls far behind other, more "popular" ailments for research.

Algorithms are even less understood than synapses. It is a mathematical term which is illustrated by a tree structure. It refers to the sequence of events necessary to produce a result. It is a way of making things very intricate so there are lots of chances for input before a final decision is taken. It's like a giant corporation where everyone is afraid to make a decision until there has been lots of input and consideration. Current research indicates that most of the things the brain does involves incredibly complicated algorithms.

Researchers thought that pain, the most important sensation to the brain, would have the decency to be simple. After all, pain feels like such a straightforward sensation. Shouldn't the generation of pain signals be simple? If that were even partially true, we would already have a cure for pain. There is every evidence that pain filters its way through to our consciousness through algorithms, chemical and physical, at every step of the way. It's as if the brain has to have all kinds of controls to understand what should be painful and what the significance of the pain should be. Perhaps this is to prevent injury to the body.

When the subject under discussion is pain it is common for researchers to use the term, thalamocortical loops. This is just another way of saying that there are connections in the brain between the thalamus and the areas that register sensation. Similar to many computers and the printers attached to them, there is two-way communication between the sensory areas at the top-outer central surface of the brain and the ball-shaped thalamus straight back from the eyes, at the center of the brain, which filters every sensation coming in from the body.

Currently, one attractive and possibly true theory is that we acquire the knowledge of what signifies cell damage through our DNA. If we don't inherit this information then we acquire it either in the uterus or shortly after birth as the brain begins to learn. A template or pattern is thought to form which indicates damage and causes the brain to send out a pain message of very specific information.

It is thought that in Central Pain, by virtue of cell damage and chemical aberrations, that the brain receives a sensory message which it cannot make sense of. The brain has a top-level security force to alert it to pain and to identify the type and significance. Unfortunately, whatever messages reach the brain in Central Pain are confusing and indistinct, it does not fit any previously formed template. The signal says pain to the brain, but it simply does not make sense. The brain utilizes all of its resources to analyze what appears to be pain, but fails in its analysis. Like a vicious cycle, the brain allocates more and more resources to try to sort out the pain, until there is a danger of cell death.  At this point, the inhibitory mechanisms (like others we will use the all-purpose term, "GABA-ergic") kick in to prevent cell death. These mechanisms shut off blood flow to the most endangered parts of the brain. What continues to get through is sufficient to put out a pain message. This is thought to be the way Central Pain works. If it is accurate, it would explain why a brain which cannot make sense of the pain at a microscopic level cannot make sense of it at a verbal level either.

Regardless of the accuracy of the above hypothesis, it does appear that a pattern or template exists in the brain to identify damaging input, which the brain turns into pain. The message traveling to the brain from the thalamus is almost certainly abnormal since PET scans show that the thalamus is shut down, or not working correctly, in Central Pain, even as it experiences jolts of powerful pain signals called bursts. The bursting (violent pain signals) can be detected electrically in the thalamus of patients with Central Pain. The thalamus is really in two halves, with one for each side of the brain, but it is common to speak of the thalamus as singular, since the two halves seem to work so closely together.

The above explanation is attractive because it makes the conscious experience of Central Pain match the suggestion of a brain that is failing to make sense about pain. One of the tragic aspects of Central Pain is that there is no adequate vocabulary, either within the brain, or verbally. Thus, it is virtually impossible for Central Pain to make sense to either the patient or the physician.

Clinicians are used to wonderfully accurate descriptions of pain, with very specific answers to questions.  When a patient cannot make sense about pain, it is offensive to the doctor, who is accustomed to better treatment and the patient is ostracized. They blame the patient for the inadequate description. It's common for Central Pain patients to enrage or anger their doctors. Being really sick, the Central Pain patient is often speechless and can do nothing but slink in desperation from the office.

The vagueness of Central Pain symptoms informs science of the struggle going on in the brain to understand the sensory input. It does not mean the patient is not suffering.

It is absolutely essential that the physician come to understand that Central Pain isn't supposed to make sense. The difficulty of description is an instant diagnostic clue, not a reason to ignore the patient. We will now state the obvious:

"Indescribable pain cannot be described, but it is nevertheless real".