The summer heat is oppressive. Mr. M, seated beside his pool, looks at the cold water. "What could be better than a refreshing dip?" he thinks. He dives headfirst into the water and takes a couple of powerful strokes. Then, suddenly, he stops. He exhales, sinks to the bottom and simply stares straight ahead. "I'm drowning," he realizes, strangely unperturbed. He knows that a few strong kicks would bring him back to the surface. But he can't quite bring himself to do so.

As luck would have it, his daughter has been watching from inside the house. She runs out and dives into the pool to save him. The sight of his daughter shakes Mr. M from his apathy, and just as she reaches him he propels himself upward, breaking the surface and gasping for air. Later he tells his family, "I don't know what was wrong with me. I just didn't want to swim anymore."

What was happening in Mr. M's brain as he came within seconds of drowning? How could he so abruptly lose all desire to act, even to save his own life?

Neurologist Dominique Laplane first described such bizarre behavior in 1981. A doctor at the Hôpital de la Salpêtrière in Paris at the time, Laplane called the phenomenon "PAP syndrome," from the French perte d'auto-activation psychique, or "loss of psychic autoactivation." (Subsequently, other experts have also labeled the condition "loss of mental self-activation" or "athymhormic syndrome.") Since then, scientists have come to learn that damage to certain areas of the brain causes patients to lose their motivation as well as their ability to reach decisions. It is as if they have become mere spectators to their own lives, no longer actively participating. By examining the brains of these patients, researchers are finding initial clues to how willfulness arises in all of us.

Yes, I'm Starving
Within only a few weeks after the pool incident, Mr. M's personality underwent a drastic change. The normally active and energetic man became increasingly passive and apathetic. He spent entire days in bed yet felt neither boredom nor impatience. His family had to remind him constantly to carry out the most basic activities: "Come to dinner! Get dressed! Take a shower!"

Such complete lack of motivation is the most obvious symptom of PAP syndrome. If left to their own devices, patients will remain in bed or on the couch for hours or even days, doing nothing but lying there awake or asleep. They do not make any plans for the future. Hobbies no longer interest them. Their utter spiritlessness extends even to fundamental needs; Mr. M's wife said her husband would have starved to death had she not intervened. Yet he never complained of hunger.

Incredibly, PAP patients do experience hunger and pain. They simply lack the will to react. Such inaction injured one 18-year-old woman examined at the Hôpital de la Timone in Marseille, France. During a visit to the beach, her parents had left her sitting in the shade while they went on an afternoon trek. As the sun moved across the sky, the woman became exposed to the scorching rays and remained there for several hours. She felt the heat but did not make any effort to take cover and suffered second-degree burns.

PAP patients require external stimuli to spur them on. Once they are encouraged, however, they can carry out complex activities as well as they once had. The patients do not often speak, but when asked direct questions they offer rational answers about their strange behavior. PAP patients also pass intelligence and memory tests, as long as the examiner keeps urging them to continue. Unfortunately, the effects of external stimuli are only temporary. Soon enough, patients revert back to silence and apathy.

What is going on in these patients' heads? What are they thinking? PAP patients often respond, "Nothing." Is that even possible--to be fully awake yet not thinking about anything for hours on end? Evidently so: patients generally describe their mental state as "empty."

Surprisingly, they do not suffer psychologically from this inertness. They are almost incapable of experiencing emotions. A once fun-loving, now fully apathetic 70-year-old teacher described her reaction to the death of her nephew this way: "It's quite tragic. Before, I would have been totally devastated. But now, it's really not such a big deal." Although patients recognize tragic or joyous occasions as being such, they can no longer sense or express sadness or joy. Their "feelings," Laplane notes, are more of an intellectual nature than actual feelings.

Some patients develop obsessive behavioral disorders--senseless, repetitive activities such as repeatedly turning a light or the television on and off. While lying in bed, one patient could not stop himself from continuously counting the ceiling tiles. At times patients irritate people around them with verbal tics, such as constant use of profane words. The cause of these pointless patterns is not known, but perhaps the brain is attempting to fill the mental emptiness.

Motivation Switched Off
PAP syndrome brings to light an important question facing brain researchers today: How is motivation created to trigger behavior? In PAP patients such as Mr. M, motivational mechanisms seem completely inactive. The patients ignore internal signals necessary to survival as well as social, moral and civil obligations--the so-called higher aspects of motivation. In addition, they are unable to see themselves in any kind of future scenario and cannot comprehend the consequences of their inactions.

Using processes such as magnetic resonance imaging (MRI), researchers have recently begun to unveil the secrets behind this condition. So far in every case of PAP syndrome, an acute illness has been found that affects some area of the basal ganglia deep inside the brain. The ailments have varied from lack of oxygen caused by clogged blood vessels to carbon monoxide poisoning. Two large tumors were discovered in Mr. M's brain; the larger of the two, in the left hemisphere, was putting pressure on his basal ganglia.

The basal ganglia are long, thin structures that have strong connections to the pathways that bring information from sensory organs to the motor regions (which tell muscles to move). The basal ganglia also connect to the frontal lobe, where problem solving, planning and decision making are done. MRI studies show that in many PAP patients the frontal lobe is not functioning properly. When working on thought exercises, this area is considerably less active than it is in healthy subjects.

People who have experienced other kinds of damage to just the frontal lobe have symptoms similar to those of PAP patients. They, too, are apathetic and fail to organize activities for the future. Together the basal ganglia and frontal lobe steer motivation and therefore an individual's will. The basal ganglia determine whether or not the frontal lobe should be activated. They act as a "switch" that can turn on or off our desire to act.

But if the connection between those structures has been impaired, why do PAP patients still act on external stimuli such as a daughter's face or a wife's command? Because other pathways can also affect motivation. For example, the frontal lobe can be directly activated by certain areas of the cerebral cortex, including the language centers. When Mr. M's family members speak to him, the language stimuli travel not only to the limbic system but also to the language areas in the frontal lobe. Having been activated in this way, the frontal lobe can make a determination and prompt Mr. M to eat or take a shower. For a moment, he can reconnect with his normal life, thanks to the intervention of a personal prompter.

Then it is back to the couch. Or the bed.

PAP syndrome is relatively rare, so little research has been done on how to aid these hapless people. It is unclear whether certain psychotropic drugs can help. Although to observers a victim's symptoms may seem to mirror depression, most patients, such as Mr. M, do not seem particularly upset about their apathy, so they may not be depressed in the clinical sense or respond to common antidepressants. And it may be hard to help patients whose symptoms have been brought on by a brain-damaging event such as a stroke until medicine finds a way to compensate for such damage. More research is needed into ways to relieve PAP symptoms. As is sometimes the unfortunate case with people who suffer psychiatric ills, medicine has little to offer, and families or friends of PAP patients may have little choice but to constantly prod their loved ones along.