Zurich  - "Damn. Now where was that card with the lemon?"

While the mother is still racking her brains, her small son has already found the lemon and correctly turned up three other pairs of memory cards as well. He sees the game as a picture and remembers the details, while she tries to use reason and does not use her brain effectively.

With increasing age, a person's frontal lobe declines both in function and volume if it is not constantly challenged. Lutz Jaencke, a neuropsychologist and professor at Zurich University, describes this process as "use it or lose it."

He advises people to train their attentiveness and concentration as they grow older. But Jaencke considers many common memory exercises to be useless - crossword puzzles, for example, particularly for older people who fill in the squares very quickly.

"That's an automatic process. The brain's control functions aren't used," Lutz pointed out. He said there was a training benefit only when the frontal lobe took part in the exercise, which resulted in fatigue.

Dr Hans Georg Nehen, director of the gerontology clinic at St Elisabeth Hospital in Essen, Germany and chairman of the German Association for Integrated Memory Training (BVGT), also recommends different exercises. "When you're stopped at a red light, think back: How many intersections have you passed?" he suggested. Even a little training helps, Nehen said.

Markus Hofmann, a memory trainer in Munich, has a similar view. "Taking on new mental tasks every day activates the brain," he remarked. That, and not always doing the same things, is real mental jogging, he said.

"Brush your teeth with your left hand sometimes, take a different route to work, read the newspaper turned upside-down or direct the music on your favourite CD," Hofmann advised. As happens when a person is learning to play a musical instrument, completely different areas of the brain are stimulated, new brain cells are activated and the connections between the cells - the synapses - become more efficient, he said.

To help train memory, new information must have a purpose, however. "It doesn't make much sense to learn a telephone number by heart. The gain would be scant," Jaencke said. "The gain is larger when I learn something that benefits me - a foreign language, for example, which I can use during my next holiday," he said. Then the brain is especially active.

The mind can be trained especially well in combination with movement. As Nehen explains it, a person who is moving about has, unconsciously, a stable sense of space. At a certain level, the person's brain is already activated. "If memory training is added, even more brain regions are included," he said.

It is also important that memory training be enjoyable. Fun, Hofmann noted, is a vehicle that carries knowledge into one's long-term memory. When a person feels good, his or her brain releases neurotransmitters such as dopamine that nerve cells need to pass on electrochemical impulses.

"Memory depends a lot more on emotions than we suppose," Nehen said. The brain definitely needs emotional stimuli to stay sharp. There is a reason that we say "to learn by heart," and the French say "apprendre par coeur." Information sticks fast to your mind only when your heart is in it. (dpa)