We Are Our Brains (17 page)

Epilepsy

People with epilepsy often suffer from sexual dysfunction, partly as a result of their medication and partly because epileptic activity in the brain disrupts the functioning of the hypothalamus. In temporal lobe epilepsy, the activity of the hippocampus and the amygdala is altered, disrupting the hypothalamus and causing sexual dysfunction. In men this takes the form of loss of sex drive, impotence and infertility, low testosterone levels, and abnormal sperm. Women can experience irregular menstruation, excessive hairiness (hirsutism), and infertility.

Epileptics whose condition is sparked by a focus in the cerebral cortex sometimes feel as if they are having an orgasm just before a seizure, due to electrical stimulation of the brain cells in that area. A woman with a tumor of the cerebral cortex experienced sensations in the genital region as if she were having sexual intercourse. Another woman with an epileptic focus in the cerebral cortex refused
both medication and the option of an operation, as she enjoyed the feeling of orgasm that preceded her epileptic attacks.

Patients whose epilepsy is sparked in the prefrontal cortex have been shown to display all kinds of sexually tinged automatic movements, like rhythmic grinding of the pelvis or masturbation. Similarly, temporal lobe epileptic seizures can be accompanied by sexual feelings, sometimes even by the experience of orgasm and spontaneous ejaculation. They can also trigger automatic movements of a sexual nature. But temporal lobe epilepsy is often associated with reduced sexuality between attacks. Surgical removal of the temporal pole can normalize sexual function but can sometimes also result in hypersexuality and Klüver-Bucy syndrome. These opposite effects call for better research into the exact location of the focus and the borders of the operative lesion and better study of any changes to patients' sexual behavior.

Considering the interrelation of brain structures, sexuality, and disease, it's remarkable that patients' medical files rarely contain any information about their sexual behavior. We're programmed to regard sex as an extremely private matter and apparently don't shed these feelings of embarrassment when we put on white coats.

In the old days, if a patient had to urinate constantly, the doctor would stick his finger in the urine and taste it. If it tasted sweet, the patient was suffering from
diabetes mellitus
(meaning “sweet urine flow”). If it didn't, the diagnosis was
diabetes insipidus
(tasteless urine
flow), and that meant something was wrong with the kidneys or the brain.

Every day, large quantities of blood pass through the kidneys in order to be cleaned. During this process, the kidneys recycle around fifteen liters of liquid from the waste fluid. They do this with the help of a brain hormone that inhibits the excretion of water, hence its name, antidiuretic hormone (ADH). It's also known as vasopressin because it raises blood pressure. It's a small protein produced by brain cells in the hypothalamus and transported to the rearmost part of the pituitary gland, where it enters the bloodstream.

The idea that brain cells could produce hormones was first suggested in the 1940s by Ernst and Berta Scharrer. Under the microscope they saw droplet-like structures in large brain cells in the hypothalamus and put forward the theory that they were packaged hormones ready for release into the bloodstream. This controversial notion met with great resistance from their colleagues. “They dismissed the idea emphatically, often viciously,” Berta wrote to me. Though by then an old lady, she was still angry at the memory. Opponents claimed that the droplets were just indicative of disease or of changes that occurred after death or had been produced by the staining process. The Scharrers proved these claims wrong by finding similar “nerve gland cells” throughout the animal kingdom, from worm to human. They proved to be a universal cell type that regulates many bodily processes by means of hormones. The Scharrers' observations founded the discipline known as neuroendocrinology.

Their hypothesis that these cells had something to do with the body's water management system was visionary. A hereditary defect in the DNA for ADH makes this hormone's function immediately apparent. People who inherit this condition produce fifteen liters of urine a day. I have followed a family that has had the condition for five generations. It was during my internship in 1968 in Amsterdam's Binnengasthuis Hospital that I first met them. At that time, the family's life was largely dominated by urinating and drinking. One of the family members told me that her mother, who also had the condition,
grew so annoyed with her children (with whom she shared a room) getting up constantly during the night to get a drink or go to the toilet that she strictly forbade them to do so, though she herself always kept a kettle under the bed to quench her own thirst. This proved simply unbearable for the children. While their mother slept, they secretly crept under the bed to suck on the kettle's spout. If they woke her up, she would slap them.

When one patient with this syndrome was admitted to a sanatorium as a child, the nursing staff were so irritated by her constant drinking and visits to the toilet that they deprived her of water for long periods. Desperate for fluid, she would drain the flower vases at night. She became so dehydrated that she would have died had it not been for the timely arrival of her parents, who restored her with a large bottle of water. If she went cycling with her sister, they always took plenty of water with them. At gas stations, each one would drain a large bottle and then refill it for the road, leaving the station attendant slack-jawed.

In 1992, working with a research group from Hamburg, we found the tiny defect in the DNA of this Amsterdam family. A single building block of the DNA on chromosome 20 was responsible for the fifteen liters of urine per day. Now people with this condition can administer long-acting ADH in the form of a tablet or nasal spray, reducing the drinks and visits to the bathroom to almost normal proportions. Some refuse this medication, though. They don't see the condition as a disease but rather as a special family trait.

FIGURE 18.
The human hypothalamus. Memory information is transmitted from the hippocampus via the fornix (1) to the mammillary bodies (2), and then routed to the thalamus (3). The suprachiasmatic nucleus (4) is the biological clock. Thermoregulation and sexual activity are governed by the preoptic region (5), while the tuberomammillary nucleus (6), the only place where histamine is produced in the brain, is important for focusing our attention. The areas that regulate appetite and metabolism are the infundibular (arcuate) nucleus (7) and the paraventricular nucleus (8). The paraventricular nucleus and the supraoptic nucleus (9) send fibers to the posterior pituitary (10), where oxytocin and vasopressin are released. The infundibular nucleus sends fibers to the capillaries of the hypophyseal portal system (12), where neuropeptides are released that regulate the anterior pituitary (11).

He came to see me together with his extraordinarily devoted mother. Since his operation she had not left his side. It gradually dawned on me that she couldn't—because she was functioning as his external hypothalamus.

Years earlier the young man had undergone an operation to remove a brain tumor, a craniopharyngioma, that threatened to destroy his sight. The surgeon did a good job, and the patient could still see well. However, up to the time of the operation, in his final year of secondary school, he had been an outstanding student and athlete. Now, after not only the tumor but also his hypothalamus had been removed, he had lost all pituitary functions and had to be given hormones to regulate those processes. That would have been the least of his problems, were it not for the extremely severe side effects of the large doses of growth hormone. His joints became painfully swollen, and he suffered from muscle pains and developed breasts. The hormones were reduced when his mother realized that the high dosage was causing the side effects, and his breast tissue was surgically removed.

His mother had to help him remember which medicines he had taken and when it was time for the next dose of hormones. In that way she replaced his memory, which had been very much impaired (see 1–3 in
figure 18
). She also stood in for his absent biological clock (4), asking that he be given the sleep hormone melatonin to combat his sleep disorders. However, nothing could be done about his complete lack of sexual activity, regulated by the front part of the hypothalamus, which had been removed along with the rest of that structure (5). There was also no solution for his memory and concentration problems, which were caused not just by his impaired memory circuits (1–3) but also by the lack of the histamine system (6), without which he could not focus his attention. The talented boy was unable to continue his studies, as his mother couldn't replace those systems. She also had to regulate the amount and composition of his meals, thus preserving him from the morbid obesity and diabetes that would otherwise inevitably ensue from the removal of the
hypothalamus (7, 8). However, by far the greatest danger threatening him was his total lack of thermoregulation (5). If he engaged in physical activity and the temperature then dropped somewhat, in a very short space of time he could develop life-threatening hypothermia, whereas if the sun came out or he warmed up, for instance by walking to the hospital for his appointment with me, his temperature very quickly rose to the level of a fever. Once, prior to an operation, the fifteen-minute wait in a hospital gown was enough to make him cool down so drastically that he nearly went into a coma, and he had to have a hot shower to get his temperature back to normal before the operation could begin. Once again, it was his mother who took over this function of the hypothalamus, following her son around with a thermometer so that whenever the surrounding temperature changed, she could take action.

The boy's situation reminded me of how many vital functions are automatically regulated by that tiny scrap of brain tissue, the hypothalamus. There was still one thing missing, though, from this story of friendly symbiosis between mother and son. “Do you ever get angry?” I asked cautiously. “No,” he said, and then suddenly stood up and shouted, “But if I ever get my hands on my brother, he'd better watch out!” Aha, I thought, a classic case of ventromedial hypothalamus syndrome. His mother, now taking on the role of the inhibiting prefrontal cortex, calmed him by putting an arm around his shoulders, saying, “That's what scares me. He flies into such rages I'm scared he might really attack his brother. He's left him in the lurch, you see. It's so tough—it makes it extra hard to cope with all his limitations.” His brother, a medical professional on a fat salary, was oblivious to his brother's terrible handicaps and the intolerable burden on his mother. The symptoms of the syndrome in question include attacks of rage, sometimes verging on the homicidal, emotional instability, bulimia, and mental deterioration. Alas, the complete removal of this young man's hypothalamus meant that he suffered from the entire spectrum of symptoms. Without the constant support
of his mother and his own extremely disciplined behavior, he would have died much earlier.