How do our brains process pain?

Posted June 06, 2013, 2:00 am

DEAR DOCTOR K:

Let’s say I stub my toe. How does my brain know where it hurts and how bad?

DEAR READER:

Pain serves as the body’s warning system. It alerts you to an injury or when something, such as an infection, has gone wrong inside your body. Pain can also help in healing. It tells you to avoid touching a wound or using a joint that’s damaged. But in order to respond appropriately, your brain must identify the location and severity of your pain.

Pain that stems from injury to body tissue is known as nociceptive pain. Examples include burns, sprains, broken bones and inflammation from an infection or arthritis. Pain from such injury is triggered by damage to little structures called nociceptors that are part of the nerve endings in the injured area. A pain-sensitive area of the body such as your fingertip or tongue has thousands of nociceptors in a tiny fraction of a square inch.

If you suffer a papercut, for example, the nociceptors in the nerve endings in the skin of your fingers are stimulated by the injury. They send a pain signal that starts at the point of the injury and travels up the nerve to the spinal cord. Then the pain signal travels up another nerve in the spinal cord to various parts of the brain. (I’ve put an illustration of the pain pathway below.)

When you bang your finger, the signal starts at the very tips of the nerve cells, travels to and up the spinal cord, and into a part of the brain called the thalamus. The thalamus sends the signals out to several parts of the brain including those that control touch, emotion, physical reaction, and memory.

Pain signals are carried by two types of nerve fibers, A-delta and C fibers. The A-delta fiber caries the first, sharp pain. The C fiber conveys the dull, throbbing pain that follows. To get to the brain, the signals travel through the spinal cord through a dense array of nerve cells known as the dorsal horn, where the gate-control action takes place, either conveying or inhibiting pain signals.

Pain signals are carried by two types of nerve fibers. The A-delta fibers carry the first, sharp pain you feel. The C fibers carry the dull, throbbing pain that follows.

Nerve fibers throughout the body connect to the spinal cord. (If the pain is in your head, nerve fibers connect directly to your brain.) In the spinal cord, incoming messages can be amplified, dampened or blocked altogether.

Pain signals reach different parts of the brain. Some signals reach the part of the brain that controls spatial awareness. It tells us where in the body a pain signal is coming from. Other signals travel to the part of the brain that generates and controls emotion. Pain signals also reach the hypothalamus, a part of the brain that controls sleep and temperature regulation.

The pain we feel can be modified by chemical signals in the spinal cord and in the brain. We know about some of them, but there are probably others that we haven’t discovered yet. Indeed, little more than 100 years ago we didn’t really know anything about how we felt pain. Human beings have been on Earth for 40,000 years, yet all we knew until 100 years ago was that sometimes we hurt.

Scientific research has taught us many things about how we feel pain, and some of that understanding has translated into new treatments. Still, we have a great deal more to learn, particularly about chronic pain — and how to better relieve the suffering of so many people who live with it.

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Enter Innovation: Improving the Fracking Process

One of the factors involved in pulling energy from shale through hydraulic fracturing is how much water is needed – typically 2 to 4 million gallons per well. Though that’s not as much water as it sounds (electrical generation for the Susquehanna River Basin requires nearly 150 million gallons per day), it’s a public concern. More on water usage at the FracFocus website.

Water also is an industry concern. It isn’t free, and once the well has been stimulated with fracking, there’s waste water that has to be disposed of or recycled. Enter innovation. A number of companies are tackling the issue.

Schlumberger’s HiWAY flow-channel technology claims to use less water, with greater effectiveness:

“HiWAY technology fundamentally changes the way proppant fractures generate conductivity. The first technique of its kind, HiWAY fracturing creates open pathways inside the fracture, enabling hydrocarbons to flow through the stable channels rather than the proppant. This optimizes connectivity between the reservoir and the wellbore—resulting in infinite fracture conductivity.”

Other companies are marketing waterless alternatives, using other agents to apply pressure to the shale – producing microscopic fractures and introducing sand or other proppants to keep the cracks open so the oil or natural gas can drain from the shale and be collected.

Baker-Hughes has developed VaporFrac, combining a high-pressure nitrogen and/or carbon dioxide gas stream and an ultra-lightweight proppant slurry:

“This method safely creates a flow stream that is more than 90% gas, significantly reducing post-frac cleanup. The high energy of the gas phase makes for easy flowback. There’s a quicker tie into pipelines.”

GASFRAC Energy Services’ liquefied petroleum gas (LPG) gel is primarily propane, which the company says has a number of advantages in fracking:

“Since our gel regains permeability with the hydrocarbons we stimulate, we have the ability to recover 100% of the fracturing fluids within days of stimulation. This creates economic and environmental benefits reducing clean-up, waste disposal and post-job truck traffic, while creating higher initial production levels.”

No doubt, other companies, other energy innovators, are at work on this question. The point here is to show the kind of invention that’s being sparked by necessity surrounding water and fracking. Businesses are taking on this issue and others associated with energy development with the goal of making processes better, safer, more efficient and more environmentally friendly. When we hear about their stories, we’ll pass them along.

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