Hamburg  - A new nasal spray boosts short-term memory while you sleep, according to a team of German scientists at a sleep research lab.

In a research report in The FASEB Journal, the researchers show that a molecule from the body's immune system (interleukin-6) when administered through the nose helps the brain retain emotional and procedural memories during REM sleep.

"Here, we provide the first evidence that the immunoregulatory signal interleukin-6 plays a beneficial role in sleep-dependent formation of long-term memory in humans," writes Dr Lisa Marshall, co-author of the study, from the Department of Neuroendocrinology at the University of Luebeck in Germany.

Marshall and her team of scientists had 17 healthy young men spend two nights in the laboratory. On each night after reading either an emotional or neutral short story, they sprayed a fluid into their nostrils which contained either interleukin-6 or a placebo fluid.

The subsequent sleep and brain electric activity was monitored throughout the night.

The next morning subjects wrote down as many words as they could remember from each of the two stories. Those who received the dose of IL-6 could remember more words.

"If a nasal spray can improve memory, perhaps we're on our way to giving some folks a whiff of common sense, such as accepting the realities of evolution," wrote Dr Gerald Weissmann, editor-in-chief of The FASEB Journal.

"This is an exciting piece of interdisciplinary science since IL-6 had previously been considered a by-product of inflammation, not an agent that affects cognition." (dpa)