Imagine That

IMAGINE THAT - How Dogs Helped Humans Think Better

Think of all the great inventions and discoveries that helped primitive humans thrive; the wheel, fire, levers, stone tool making, selective agriculture, and successful hunting strategies. We seldom attribute any of those developments to dogs, but in your mind travel back to a time when humans were vulnerable and disadvantaged compared to other animals.

Imagine sleeping in a cave with your family. Perhaps an abundance of furs and skins made your bed relatively comfortable. To stay safe from predators, your spouse’s brother, Larry, was standing watch for the first part of the night. Lulled into a false sense of safety – nothing has ever attacked us at night – he himself drifted into a light sleep. Foolish. That was the night that the big cats caught the scent of your dwelling and soundlessly approached. The largest of the cats took the lead, and pounced on the sleeping guard grabbing his face between two powerful jaws. Larry’s muffled cry only served to wake the family to witness his demise. Fierce defensive moves by you and your mate limited the loss to one child and Larry. The remainder of the night is spent trying to stop the bleeding, and staying alert to thwart additional attacks.

Thousands of years ago, your ancestors did not sleep through the night. They only napped briefly, and even then sleep was not deep. It was during sleep that rodents stole food, fire spread into bedding, baboons snatched babies, and marauding rivals took captives. Early human-like creatures, it is hypothesized, could not afford the luxury of deep, prolonged sleep because those long moments of unconsciousness could be fatal.

You might ask, isn’t sleep in small bits just as beneficial? The answer appears to be no. According to researchers sleep and long bouts of it are required for humans to thrive. We know about Rapid Eye Movement, and the benefits of REM sleep. Cornell University researcher Dr. James Maas tells us, “Good sleep is the best predictor of life span and quality of life.” With REM sleep humans are more alert, energetic, higher performing, more thoughtful and creative, and physically healthy. REM sleep usually comes after six or seven hours of sleep. Short bursts of brain activity in which neural patterns closely resemble waking brain activity occur during these vital moments. Brain waves show brief, two-second spikes of activity. When graphed the spikes resemble spindles, the term used to for these bursts of dreaming. Without sleep humans become stupid, clumsy, and unhealthy. That fits the image of cavemen, no?

Without sleep we fail to learn as quickly, and concentration is limited. According to the National Institute of Health, “lack of sleep impairs reasoning, problem solving, and attention to detail.” During sleep cerebrospinal fluid circulates through the brain removing toxic proteins and refreshing the cells. Dr. Maiken Nedergaard of the University of Rochester found that levels of beta amyloid drop significantly during sleep.

So what does this have to do with dogs? With the dog at your side, or merely guarding the dwelling from nearby, early humans were alerted to danger well before it arrived. If the predator persisted in approaching you and your family, you had the dog’s superior fighting ability and resistance to pain on your side. The dog that warned when sparks popped out of the fire onto flammable materials, also grabbed sneaky rodents before they could raid your grain hamper, or nibble your children’s fingertips. On cold nights, the dog kept the family warm. The dog sniffed out and retrieved the bird your hunting companion knocked out of the sky with the rock. The dog smelled game before you did, and telegraphed its presence with noticeable changes in body posture.

Ages ago, I hunted waterfowl with my doctor. He would sit quietly as I scanned the sky for ducks. Relax, he said, just watch the dog. The dog is watching for ducks.

Humans who slept through the night without dogs suffered from a much shorter life span. Humans who slept only lightly and for brief moments failed to develop intellectually, so they lacked creativity and problem solving capacity. The humans with dogs were able to sleep and awaken refreshed and energetic. The families that partnered with dogs, were better able to solve problems and enjoy a higher functioning culture.

We owe our human imagination, in a great part, to the dog. Now go hug your dog.

SOURCES:             http://www.nih.gov/researchmatters/october2013/10282013clear.htm

                        http://www.apa.org/monitor/julaug04/strengthen.aspx

NOTES:

From the NIH

Scientists and philosophers have long wondered why people sleep and how it affects the brain. Sleep is important for storing memories. It also has a restorative function. Lack of sleep impairs reasoning, problem-solving, and attention to detail, among other effects. However, the mechanisms behind these sleep benefits have been unknown.

Dr. Maiken Nedergaard and her colleagues at the University of Rochester Medical Center recently discovered a system that drains waste products from the brain. Cerebrospinal fluid, a clear liquid surrounding the brain and spinal cord, moves through the brain along a series of channels that surround blood vessels. The system is managed by the brain’s glial cells, and so the researchers called it the glymphatic system.

The scientists also reported that the glymphatic system can help remove a toxic protein called beta-amyloid from brain tissue. Beta-amyloid is renowned for accumulating in the brains of patients with Alzheimer's disease. Other research has shown that brain levels of beta-amyloid decrease during sleep. In their new study, the team tested the idea that sleep might affect beta-amyloid clearance by regulating the glymphatic system. The work was funded by NIH’s National Institute of Neurological Disorders and Stroke (NINDS).

From APA

James P. Maas, PhD Cornell University stressed that good sleep isn't a luxury, but a necessity. "Your alertness, energy, performance, thinking, productivity, creativity, safety and health will be affected by how much you sleep," he said. "Good sleep is the best predictor of life span and quality of life."

Sleeping and learning

Besides boosting alertness, sleep--particularly rapid eye movement (REM) sleep--is a way for the brain to store new information into long-term memory, said Maas. The brain, he explained, accomplishes this through a phenomenon that researchers have only recently come to understand: sleep spindles.

Sleep spindles--one- to two-second bursts of brain waves that rapidly wax and wane at strong frequencies, so-called for the spike image they form on an EEG reading--occur during REM sleep. The REM phase usually takes place toward the end of the night, between the sixth and eighth hours of sleep, when people are most likely to dream. In fact, Maas said, the brain's neural patterns during REM sleep resemble those of its awakened state.

During REM sleep, the brain busily replenishes neurotransmitters that organize neural networks essential for remembering, learning, performance and problem solving, he explained. Conversely, he says depriving the brain of sleep "makes you clumsy, stupid and unhealthy."