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HOW THE BRAIN WORKS
When the brain is healthy, it enables us to think, to learn, to feel, to work, and to move. But the brain is a complex piece of equipment, and sometimes it doesn’t function properly. Imagine a computer that has a serious problem with its hard drive. When this happens, the computer will act in unpredictable ways. The same is true for the brain—if the equipment breaks down or malfunctions, our thoughts, feelings, and behavior can become distorted. It might feel as if someone else is in control or as if your brain has a mind of its own.
Feeling like you have lost control is frightening. But remember, you as a person have not changed. You will be the same person when the equipment problem is corrected.
SAMANTHA: I’m forty-five years old now. Five years ago I was diagnosed with schizophrenia. Prior to that time I led a relatively normal life as a mother, wife, and breadwinner with a house in Seattle. Two years before my diagnosis, symptoms of schizophrenia started appearing and continued to grow: poor concentration, extreme distraction, irrational decisions, delusions, and auditory hallucinations. At the time I joined a church group. Following my association with this group I snapped, and everything got worse.
My life completely decomposed. I couldn’t concentrate on a simple job. I resigned from an excellent job that I had. I tried to go back to school with the idea that I was going to become a professional dancer, which was a major delusion. I also had a delusion of thinking I was a missionary in Seattle and led my life with both of these grand delusions. I spent a semester dancing, wearing nothing but tights and leotards. I took five dance classes a day. Now remember, I was thirty-seven years old then. People don’t leave great jobs to go into dance at age thirty-seven. I thought I was going to be the star dancer on the stage. My professors realized something was amiss, and after a semester at college I was asked to leave.
Special contributor: Handan Gunduz-Bruce, M.D.
SAMANTHA
I tried to go back to work again, unsuccessfully. I started having very bad problems with distractibility, wandering around, doing my own type of thing on the job, and was fired. Then I went into the next phase of my delusions, which was thinking I was a visionary.
My husband divorced me. I agreed to move out of my house. The attorney assisting me in our divorce settlement did not help. This resulted in no financial resources. So I lived in a one-bedroom apartment in an isolated part of town, walking thirteen and fourteen miles a day. I was roaming, walking, hiking, and doing good deeds whenever I came across them. On my walks I imagined voices in my head—people I knew from the church group—telling me to do these deeds. For example, I was on one of my walks on a hot, sunny day when I came across some kids playing ball without supervision. One kid fell down and hurt his knee. I thought it was my responsibility to bring him home and get medical assistance. And that’s what I did. Of course it was absolutely none of my business what these children were doing. When I returned the child to his mother I was verbally attacked. The police were called to come and arrest me for kidnapping.
I ate rice with chopped-up brussels sprouts for breakfast and dinner. I slept once every three days, did not see my daughter all month, and wore black hiking shoes, which caused my feet to bleed. I baked chocolate chip cookies every day, and that is what I lived on.
My unemployment and assistance from Seattle were not renewed. I had an eye infection that was untreated because I had no medical insurance. I had no resources to fall back on, none whatsoever. I had been seeing a counselor who was of no help. My cousin realized something was wrong and helped me make a decision to call for an ambulette to take me to a county hospital. I was in that hospital for two weeks. I didn’t cooperate with the doctors, the staff, or the program and begged my parents to help bail me out. My parents brought me back to New York. Then they began to realize that something was wrong.
MARK
MARK: It was probably the best time of my life. I was doing very well in school, very well. I was looking good, had a lot of energy, and was very happy. Unfortunately, things got away from me. I can’t say I had a reason, but they just did. The line between reality and dream gradually faded.
The biggest thing I remember is that I had no warning. It just happened: time and space distortion, things moving slower or faster, hallucinations—things looking bigger, stretching out, faces warping. I could not think logically. I was caught up in emotion. The best way I can explain is to say it’s like when you are dreaming; things don’t make sense, but you accept them. But when you dream, the brain cuts off from your body. I was awake, but I would act based on the “dream.” I would cry because I felt like crying. It was like every drug you could do, but I wasn’t doing drugs and I wasn’t in a dream. I was awake, but I thought it was all real. Then I kind of repented. I started looking for explanations. Unfortunately, the first thing that should have—but didn’t—come into my head was that I should see a doctor.
WHAT THE BRAIN DOES
Samantha and Mark’s brains were not functioning the way they had been before their symptoms appeared. Understanding how the brain works helps us understand why this might happen.
Basically, the brain is in charge of:
• automatic functions required for survival, such as heartbeat and breathing
• motor functions that are under our control, such as throwing a ball and writing
• sensory processes, such as seeing, hearing, smelling, tasting, and perceiving pain or touch
• feeling states, such as happiness, depression, anxiety, and fear
• intellectual functions, such as attention, concentration, learning, and memory.
PARTS OF THE BRAIN
The two major parts of our nervous system are the central nervous system and the peripheral nervous system. The central nervous system is made up of the cerebral hemispheres (cerebrum) and the spinal cord. The peripheral nervous system is made up of nerve cells extending from the spinal cord.
Figure 3.3 shows the gross anatomy of the cerebral hemispheres (excluding the cerebellum and spinal cord). The cerebrum consists of five parts: the frontal lobe, the parietal lobe, the temporal lobe, the occipital lobe, and the limbic lobe.
CEREBRAL HEMISPHERES
The frontal lobe is primarily responsible for the intellectual functions, personality, and some language and motor functions.
The parietal lobe processes sensory information.
The temporal lobe functions in hearing and language.
The occipital lobe plays a role in vision.
The limbic lobe has a role in memory and emotional processing.
HOW THE BRAIN SENDS MESSAGES
Neurons
The brain contains about 10 billion nerve cells known as neurons. Each of these neurons communicates with more than a thousand other neurons at connections between them called synapses. There are three parts of a neuron: the soma (cell body), the axon, and the dendrite.
The cell body is star shaped, with many protrusions on its surface called dendrites. One dendrite, called the axon, is particularly long, like a cable. The cell body contains the nucleus and the other essential components that are necessary for the metabolism of the cell. It receives electrical signals from the many dendrites on its surface and, like a computer, processes all these incoming signals to produce an outgoing signal that travels down its axon.
Like an electrical cable, the axon carries an electrical signal along its length. It can be quite long, as much as several hundred times the length of the cell body. For example, a motor neuron that carries information from the brain down to a leg muscle can be 40 inches long.
The dendrite receives signals and sends them to the cell body. Two neurons communicate at the point where an axon from one neuron comes very close to the dendrite of another. This region is called a synapse. The space between the tip of the axon—the synaptic terminal—and the dendrite is called the synaptic cleft.
The electrical impulse that arrives at the synaptic terminal of the first neuron leads to a release of a chemical substance called a neurotransmitter into the synaptic cleft. When the neurotransmitter reaches the dendrites of the second neuron and attaches to receptors on them, this triggers the second neuron to send an electrical impulse.
FIGURE 3.4
STRUCTURE OF A NEURON
Neurotransmitters
In order for the different parts of the brain to communicate, the neurons that connect them must be able to send their electrical signals properly. This depends on the ability of the neurotransmitters at each synapse to relay signals from one neuron to the next. Some brain disorders are due to a defect in the ability of one neuron’s neurotransmitter to stimulate another neuron to act.
There are different kinds of neurotransmitters. Some are found throughout the brain; others are found only in certain parts. Several neurotransmitters are thought to play a role in causing the symptoms of schizophrenia. One of them is called dopamine, and another glutamate.
Dopamine is mostly found in the basal ganglia, a region of the brain located in the base of the cerebrum. Most of the older medications used to treat psychotic symptoms work by reducing the activity of the dopamine in this area of the brain.
Glutamate is present all over the brain, and it is a major neurotransmitter that causes excitation on a neuronal level. Several recent genetic studies suggest that genes that play a role in glutamate regulation may be abnormal in schizophrenia.
STRUCTURE OF A SYNAPSE
There are special proteins on the surface of the receiving neuron called receptors. They receive the neurotransmitters coming from the sending neuron. When a neurotransmitter attaches to a receptor, the receptor responds by setting a chain of events into motion. For example, a receptor may start a process whereby the neuron will release its own neurotransmitter or secrete a hormone, depending on the neuron’s specific function.
The complexity of the brain is due to the very large number of connections among the brain lobes as well as within each of them. These connections carry information between different parts of the brain as it performs its operations. Therefore, when one part of the brain is affected by a disease, several other parts can be affected as well. For example, a person who suffers a stroke may have muscle weakness, difficulty with speech, and feelings of depression. A person with schizophrenia may have poor concentration and memory problems; they may also experience unusual sensations such as hearing voices, seeing visions, or having unusual thought patterns.
The brain is like the Internet. Signals get sent and are received among many parts of a complicated system.
Let’s look at a very simplified example of the brain at work. Your friend accidentally steps on your foot. The nerve cell (neuron) in your foot sends the feeling of pain on to the nerve cell in your brain. But there is a space (synapse) between the two cells. To move the message, the neuron needs a messenger. The messenger, dopamine—a kind of neurotransmitter—carries the impulse from the axon across the synapse to the dendrite of the next neuron. There a receptor is waiting to attach itself to the dopamine. It carries the message to the home base (cell body). The message gets interpreted, and you feel pain in your foot.
Now, what if there is a chemical imbalance? What if there are too few or too many dopamine or receptor chemicals? Imagine a toy train set. Too little power and the train stops. Too much power and the train flies off the track. That is what happens when you are experiencing symptoms of psychosis. The message gets confused. You might think your friend purposely stepped on you.
Additional information about the brain:
The Scientific American Day in the Life of Your Brain, by Judith Horstman (Jossey-Bass, 2009).
