Talk about the healing power of magnets sounds very "new age". And many alternative practitioners do believe that magnetic devices can help to relieve pain, for example. But orthodox medicine is also beginning to discover that magnetic stimulation of the brain can bring unexpected results, from relieving long-term depression to speeding up some thought processes.

Although crude attempts to influence the brain with powerful magnets were made back in the 19th century, serious scientific experiments started in the 1980s with the invention of a technique called transcranial magnetic stimulation. A small electromagnet with metal coils in a figure-of-eight shape is held against the skull. It produces magnetic pulses which in turn induce a local electrical current in the brain, just below the coils.

The first TMS machines were used for diagnosis and research. For example, if a neurologist can stimulate the motor part of the brain and make the patient's thumb twitch, the intervening nerve pathways must still be intact. TMS has also helped researchers map in more detail areas involved in particular mental processes by using the magnetic field to shut down a small part of the brain.

The effect of inducing a virtual or temporary lesion in this way can be dramatic: if you are counting "one, two, three, four . . ."and a TMS device is activated on a particular place on your forehead, you suddenly lose the power of speech and stutter "fi . . . , fi . . . , fi . . ."; when it is switched off, you carry on counting normally.

By all accounts TMS is painless and a single experience has no permanent effect on the brain. But in the early 1990s neurologists began to ask whether repeated TMS could have beneficial long-term effects for some psychiatric patients.

The answer seems to be yes. Over the past five years several trials have shown that TMS can relieve severe depression in at least half of patients who do not respond to antidepressant drugs or cognitive therapy. The Canadian authorities have approved TMS to treat depression, but in most countries it is still restricted to clinical trials. A typical programme consists of half-hour TMS sessions once a day for two weeks.

Repeated exposure to magnetic fields seems to reset the brain circuits that control mood, and TMS is emerging as a gentler alternative to electroconvulsive therapy, currently the most effective treatment for severe drug-resistant depression. ECT shocks the patient out of a depressive mindset by inducing a mild brain seizure. But it is not clear how TMS or ECT works.

TMS may also help people suffering from other brain disorders. It shows particular promise in treating schizophrenics who "hear voices". About 70 per cent of patients with schizophrenia suffer from auditory hallucinations, says Ralph Hoffman of Yale University. "Voices are particularly disabling, often producing great fear in patients and, at times, lack of control, leading to behaviours such as suicide and assault."

Hoffman and colleagues have applied TMS to the speech processing area of the brain by holding the coil against the patient's scalp above and behind the left ear. Preliminary results from their latest trial show that about two-thirds of patients have at least a 50 per cent reduction in hallucinations after a course of nine TMS sessions; the duration of improvement ranges from two weeks to many months.

Meanwhile, brain researchers are making remarkable discoveries about the effects of magnetic stimulation on the normal brain. Depending on the location and frequency of the electromagnetic pulses, TMS may either improve or impair mental performance.

For example, US researchers at the National Institute of Neuro logical Disorders and Stroke found that magnetic stimulation of the brain's prefrontal cor-tex enabled volunteers to solve analogy puzzles - working out relationships between geometrical shapes - more quickly.

There are two distinct ways in which TMS might speed up thought processes. One is to increase the underlying level of neural activity in the brain region involved, enabling it to respond more quickly when asked to perform a particular task. The other possibility is that the magnetic stimulation might shut down other competing regions, so that the brain can concentrate better on the task. This links TMS research to two apparently disparate subjects: autism and mobile phones.

A few autistic people, "idiot savants", have remarkable calculating skills - for instance, being able to tell you what day of the week May 2 2051 will be. One theory is that most of us have the mental capacity to calculate like a savant but a barrier of higher-level concepts nor-mally blocks access to it.

Experiments in which TMS improves volunteers' mathematical performance hint at the possibility of developing technology to suppress other thought processes, so that anyone could become an arithmetical genius, though the side-effects might be too damaging.

Research by Alan Preece at Bristol University suggests that a weaker electromagnetic field, simulating the effect of a mobile phone held close to the ear, can temporarily speed up mental reactions, though the effect wears off quickly when the field is switched off. It seems that most of the population may be indulging unwittingly in magnetic brain stimulation.

This Article has been submitted by the Jeremy's Prophecy Dot Com team for informational and educational purposes. Jeremy's Prophecy Dot Com is a website dedicated to telling the story of Jeremy Jacobs, a character in the novel, Jeremy's Prophecy Dot Com.