In contrast to land mammals, dolphins developed the ability to sleep with only one part of their brains at a time. While half of their brains rests – and dreams – the other half remains awake and alert. This finding explains how dolphins can keep a constant lookout for their pod mates and predators, like sharks. Dolphins regularly alternate the active side of the brain. If they stopped whole brain activity and slept like humans do, they would probably become easy prey or even drown.

In a clever experiment, researchers tested how “mindful” dolphins are with just half their brain. Because dolphins use echolocation to map the world, the investigators set up a portable floating pen outfitted with eight modules, each consisting of an underwater sound projector and microphone. During echolocation, an animal produces a sound and listens to returning echoes to gain information about its environment. So when a dolphin scanned any of the eight modules using echolocation, they were able to respond to the signal with sound-mimicking echoes of signals from remote surfaces. Essentially, these modules could behave as “phantom targets.”

Trained to respond to these signals for a year, in the experiment the dolphins could eventually successfully use echolocation with extremely high accuracy and no sign of deteriorating performance for up to 15 days straight! The researchers stopped the experiments at that point. but they suggested dolphins could continue much longer staying alert and doing tasks, perhaps indefinitely. Isn’t it amazing that the dolphins showed no sign of losing their sharpness as the days wore on?

“These majestic beasts are true unwavering sentinels of the sea,” said Branstetter, according to Live Science.

Future research will include monitoring the dolphin’s brains for electrical activity via electroencephalogram, or EEG.

“Research with freely moving humans who wear portable EEG equipment has been conducted; training a dolphin to wear a similar portable EEG backpack that is capable of withstanding and functioning in an ocean environment presents much greater challenges,” Branstetter said. “However, these hurdles are not insurmountable. Also, we are interested in investigating if dolphins can perform more complex cognitive tasks without rest, like problem solving or understanding an artificial language,” Branstetter added.

If the ability to keep half the brain turned on while the other is getting a good rest is an evolutionary adaptation to protect against predators, it makes me wonder why humans didn’t also developing this ability? On the other hand, nothing is more fun than getting a good night’s sleep and bending the laws of gravity in your dreams! So for us humans it is: Keep calm and sleep on!

The study was published in PLoS One. 

Biologists would like to understand how a bear, who eats continuously throughout the summer to lay down fat reserves for the winter, can have cholesterol levels that would be high for a human, but not suffer the hardening of arteries that one might expect. And what about the bone loss one would expect from months of inactivity?  Humans on bed rest can lose 3-4% of their hip bone minerals from lack of weight bearing exercise.  Bears show no signs of bone loss or osteoporosis as a result of their long rests.  It is likely that the genes involved exist in our cells too, but they just aren’t being used in the same way.

We clearly have a lot to learn from our hibernating friends. Teams of researchers in Sweden have actually been studying Brown bears to learn about these interesting phenomena.  How do you study wild Brown bears you ask?  You tranquilize them while they are hibernating, collect as many samples as you can, and get out before they wake up!  For the full story on hibernation, go to: http://www.sciencenews.org/view/feature/id/338318/title/Lessons_from_the_Torpid.

Researchers at the University of Wisconsin- Madison conducted tests with rats that were kept up past their normal bedtime. The rats were given objects to play with to keep them awake. During play, electrodes were implanted in their brains to measure brain activity. The results were interesting.

It seems that sleep does not involve the whole brain at once. It was once believed that a central control system determined when the brain would sleep and then later when it would wake. However, due to new research, this doesn’t seem to be the case. It seems that individual cells make the decision to sleep which eventually spreads throughout the rest of the brain.

The rats that were “wide awake” and playing with their toys weren’t “wide awake’ at all! Parts of their brain were snoozing- as the electrodes showed. This means that even though the rats weren’t showing their sleepiness and weren’t nodding off, their brains were not working to their full potential.

The electrodes measured activity in two parts of the brain: the motor cortex and parietal cortex. The rats were given an activity that required them to reach through a plexiglass wall and grasp a sugar cube. The rats that had a napping motor cortex (the part of the brain that controls movement) failed to grasp the sugar cube after many mistakes. The rats that had a napping parietal cortex, however (which was not needed for the task) was able to complete it without any mistakes.

As to how this would apply to the human mind, this could mean that the loss of sleep can be even more dangerous than previously thought. Someone could feel awake enough for tasks without realizing that essential parts of the brain are dozing. This can lead to slips of the tongue, driving mistakes, errors of judgment or other problems. It makes us rethink sleep derivation and how it’s really affecting us.

Just another reason why getting the recommended amount of sleep is important!

In an August article from Scientific American, a rare genetic mutation has been identified on a gene called DEC2 that causes it’s carriers to become “short sleepers”, meaning they need less sleep! Two women, a mother and daughter, who have this mutation require only 6 hours of sleep without a negative impact. Apparently they can do this because they have a more efficient sleep, with more intense REM states, which was observed in mice with the same mutations.

Why is this important, you may ask? Someday this will help scientists in the treatment of certain debilitating sleep disorders. On a more selfish note, it might even help scientists to develop a biological treatment that allows us regular folk to function just as well as we already do, with less sleep. Just think of the things you could accomplish with a few extra hours!