play an especially critical role in our ability to respond to events happening around us. The manner in which we respond, however, is the result of brain conditioning, much like the conditioning of our muscles during physical exercise or training.
Figure 1.1: Main Components of the Developed Brain
Hypothalamus/Pituitary: The Brain’s Thermostat
The lower area of the brain contains a section called the hypothalamus. Known as the body’s thermostat, the hypothalamus maintains homeostasis, the constant state in which our body operates. Functions such as heart rate, blood pressure, body temperature, growth, metabolism, electrolyte balance, hunger, sleep, wakefulness, and breathing are controlled by signals generated by this area of the brain.
In order to function properly and direct the brain, the hypothalamus receives signals from the skin, eyes, nose, peripheral nerves, and the multitude of internal receptors that respond to changes in temperature, fluid concentration, and pressure. Because it’s so sensitive to stressors and environmental signals, the hypothalamus is also involved in an immense number of biochemical reactions, and is the reason why stress can have such a deleterious effect on so many different organ systems. Altering the hypothalamus surgically, for example, can literally destroy the immune response.
Directly below the hypothalamus is the pituitary, which releases more hormones than any other endocrine gland. But although it’s the principal gland that releases hormones (it’s called the master gland of the body), the pituitary cannot do so without chemicals produced by the hypothalamus. The anterior pituitary is involved in many of the reactions occurring during stress, anxiety, and physical trauma. A pathway comprising the hypothalamus, pituitary, and adrenal gland plays an important role in how we deal with both physical and emotional stressors and is discussed in the next chapter.
The posterior pituitary releases two hormones, one of which, vasopressin or antidiuretic hormone (ADH), is important in regulating the body’s fluid balance. During stress, it also contributes to the release of cortisol, which depresses the immune system and makes us more prone to illness and disease. In the case of major depression, both vasopressin and cortisol levels are very high. Oxytocin, the other posterior pituitary hormone, is mainly involved in muscle contractions, especially the uterine muscles during the final stages of pregnancy and the mammary gland cells during suckling in order to eject milk. In males, oxytocin increases contractions of the prostate gland and the vas deferens, the vessel that transports sperm.
Recently, a team of scientists from Heptares Therapeutics, a medical company in Hertfordshire, England, discovered the structure of what has been called the brain’s “misery molecule.” According to the scientists, CRF-1, a protein found in the brain and pituitary cells, triggers the release of stress hormones and may actually contribute to our feelings of stress, anxiety, and even depression. Chief scientific officer Fiona Marshall said that “Stress-related diseases such as depression and anxiety affect a quarter of adults each year, but what many people don’t realize is that these conditions are controlled by proteins in the brain, one of which is CRF-1 found in structure of class B GPCR corticotrophin-releasing factor receptor 1.” The team soon hopes to develop drugs that can block CRF-1 and blunt the release of chemicals responsible for stress reactions.1
A network of nerves above the hypothalamus, the limbic system is often referred to as the emotional brain. It has a large number of sensory receptors and the greatest concentration of the brain’s opiate receptors. The rush or feeling of euphoria one gets after taking an opiate such as heroin or morphine is caused by the binding of such drugs to these opiate receptors.
The limbic system controls and regulates emotions such as fear, rage, love, hate, sexual arousal, aggression, pleasure, and pain. Located here are the so-called punishment and reward centers, believed to be important in learning and in triggering the motivational systems behind behavior that seeks to avoid pain and pursue pleasure. Different areas of this system elicit different responses. Some years ago, I worked with a research scientist who was investigating how tobacco additives could be used to stimulate the areas of the limbic system that produce pleasure responses.
One part of the limbic system important in learning and memory is the hippocampus. Whenever we learn something new, structural changes occur that allow us to remember. New evidence from Alzheimer’s patients shows that there is considerable atrophy of the hippocampus, which would explain the loss of memory and the inability to recognize even recent experiences. Neuroplasticity is essentially lost, and the brain can no longer file away information.
It’s also believed that the limbic system is the part of the brain most involved with violent behavior. For example, as part of a classic medical experiment, a woman had an electrode inserted in one section of her limbic system and received a mild current. She immediately became angry and violent. When the current was switched off, she again became pleasant and cooperative. There’s agreement among neuroscientists that disruption of nerve impulses within the limbic system may be responsible for at least some cases of violent behavior.
Like all other areas of the brain, the limbic system is affected by a number of external signals from the environment, as well as by internal signals we send to ourselves because of the way we think and how we perceive events. No organ is more prone to suggestions than is the brain; and no organ in the human body is more responsive to how the body responds to those suggestions. Fighting a cold or eliminating a tumor often depends in part on the positive signals we send, which in turn unleash a wave of chemicals that trigger the massive immune response that stops disease in its tracks.
In research studies, nearly one-third of patients given nothing more than a placebo—often a sugar pill or a distilled water and salt solution—improve their condition. Why? Obviously something powerful takes place in the brain of the patient. As Dr. Robert DeLap, then head of the US Food and Drug Administration’s (FDA) Offices of Drug Evaluation explained in the Jan/Feb 2000 issue of the FDA publication The Healing Power of Placebos, “Expectation is a powerful thing. The more you believe you’re going to benefit from a treatment, the more likely it is that you will experience a benefit.” This is exactly why placebos are used when testing a new drug’s medical benefit. If patients on the new drug fare significantly better than those taking a placebo, the study helps support the conclusion that the medicine is responsible for improvements in patients’ condition and not the power of positive thinking.
For centuries, unorthodox treatments have produced astounding improvements in health that could not be explained in traditional terms. During the last few decades, researchers have been studying how the placebo effect triggers the mind to regulate and control the body. In 1955, a groundbreaking paper “The Powerful Placebo” demonstrated that 32 percent of patients responded to placebos. Ten years later, breakthrough studies demonstrated that placebos sped up pulse rate, increased blood pressure, and improved reaction speeds when participants were told they had taken a stimulant, but had the opposite effects when participants were told they had taken a sleep-inducing drug.
It’s hard for many people to accept the notion that just thinking about curing a disease will often be enough to actually do it; that we can respond as well to an inert pill as we can to an actual drug. But according to Dr. Michael Jospe, a professor at the California School of Professional Psychology, who has studied the placebo effect for more than twenty years, our belief system gives us more healing power
