Chicago (IL) - The human fetus spends the majority of its growth time after the seven month mark asleep. Until now it was a mystery whether or not the brain cycled during sleep or remained inactive. Now, scientists know the answer.
Utilizing sophisticated mathematical techniques for detecting patterns, a Friedrich Schiller University in Germany team found that immature fetuses are capable of entering into a state in which they dream, just weeks prior to the first appearance of rapid eye movement. Scientists based their discovery on the analysis of the sleeping patterns of immature sheep fetuses.
The team discovered cycles in the complexity of immature brain activity. Unlike the patterns of sleep, which occur in the later stages of development, the cycles fluctuate every 5 to 10 minutes and change over time as the fetus grows.
The scientists recorded electrical activity in the brain of a 106-day-old developing sheep fetus directly; this had never before been accomplished.
Sheep were utilized in this study because they carry one or two fetuses which are similar in both weight and size to that of humans. Additionally, the brain development in humans and sheep is also quite similar, in humans it lasts 280 days, and in sheep 150.
The scientists say it was difficult to imagine what the fetus experiences throughout these cycles in terms which make sense to adults; however the patterns will help to depict origins of sleep.
"Sleep does not suddenly evolve from a resting brain. Sleep and sleep state changes are active regulated processes," team leader Karin Schwab said.
These findings will help scientists to determine why we need to sleep, and how one can use these patterns to determine optimal growth, and optimal health of individuals from an early state of life.