Unborn babies' sleep patterns have been an enigma for researchers since modern observation techniques have been devised. Measuring the brain activities of people sleeping is easy when they are outside the womb. Electroencephalograms can yield a pretty detailed insight into someone's subconscious mind, and the readings gathered help doctors or researchers in their work. Just recently, scientists have begun to answer the decade-old question of whether the brain of immature fetuses cycles with sleep, or if it simply remains inactive until it properly develops.

A new scientific paper, published in the American Institute of Physics' (AIP) journal Chaos, a German researcher team at the Friedrich Schiller University in Jena, comprised of mathematician Karin Schwab and a group of neuroscientists, seem to think that even fetuses younger than seven months can dream.

The team base their conclusions on the fact that very immature sheep fetuses were observed to enter a “dreaming,” sleep-like state weeks before the first signs of rapid-eye movement (REM) sleep occurred.

Sheep fetuses were selected for this study on account of the fact that they were the approximate equivalent to human ones, in terms of size and weight. Their brain, however, needs only 150 days to develop, while the human one some 280. For the first time ever, the German researchers recorded the electrical activity in the brain of the sheep offspring directly, while it was still in its mother's womb. The study began when the fetus was 106 days old, and lasted until the end of the pregnancy.

“Sleep does not suddenly evolve from a resting brain. Sleep and sleep state changes are active regulated processes,” Schwab said after the study was completed. Using very complex mathematical formulas, which could detect patterns in recorded data, the researcher was able to conclude that the sleep cycle of the sheep brain fluctuated every five to ten minutes at the beginning of the study, and then changed slowly as the pregnancy progressed. This discovery could have major implications for the international sleep research community, in which the topic of whether sleep cycles suddenly appear at seven months of development or over time is still highly debated.

This type of finds may very well offer experts the key to understanding how impairments in these sleep cycles cause diseases in the mature human, or at least trigger susceptibility to certain kinds of medical conditions. In addition, such studies could also reveal basic information about the purpose that sleep serves when the fetus develops. Some hypothesize that the most intricate parts of the human brain form their connections during these cycles. Throughout the “wake” period, these connections are believed to be embedded in the brain for good.