April 15, 2009

Fetal sleep patterns are identified

German scientists say they've discovered very immature sheep fetuses can enter a dreaming sleep-like state weeks before rapid eye movements develop.

The Friedrich Schiller University researchers in Jena, Germany, led by mathematician Karin Schwab noted that after about seven months growing in the womb, a human fetus spends most of its time asleep. Its brain cycles between rapid eye movement sleep and the quiet resting state of non-REM sleep.

But whether the brains of younger, immature fetuses cycle with sleep or are simply inactive has been undetermined.

Schwab and her colleagues said their discovery, made by using a mathematical system, provides a tool to study how the brain develops and to identify vulnerable periods in brain development when damage could lead to disease later in life.

The research appears in a special issue of the journal Chaos, focusing on non-linear dynamics in cognitive and neural systems.