All children, if given the chance, will play, preferably with other children. The games they play

are often creative, rough and tumble, and of course―fun. Some consequences are obvious:

·         Fun is a positively reinforcing emotion. It makes kids happy.

·         Play encourages exploration with fewer constraining boundaries than the drone of regular life.

·         Play is an effective way to socialize and make friends.

·         Play stimulates initiative and engagement, rather than passively observing what others do.

But there is another less obvious reason, one that is biological. In a review in the American Journal of Play (yes, there really is a scholarly journal on play), evidence is provided from controlled studies in rats and some primates. These studies show that when young animals are encouraged to play they develop improved social competence, cognition, and emotional regulation later in life. Play experience also makes them more adaptable to unexpected situations.

It is true that play is not a developmental feature in all species. The capacity (and need) for play is most evident in higher mammals with developed neocortex and that live in complex social environments. Play fighting is adaptive in predator species, like bears and lions that depend on aggression for survival as adults. In all species that exhibit juvenile play, play is a developmental tool that promotes the neocortical executive control regions to control other neural systems.

Play fighting is especially interesting because the juveniles must construct and obey certain rules. They intuitively recognize that they must not bite too hard, for example, and must give the opponent at chance to win sometimes or at least hold their own in the contest. The juveniles are clearly learning self-control, which will serve them well as adult. This reminds me of the touch football games that kids play.

Species that most obviously exhibit juvenile play are humans, dogs, cats, and ravens. In species where adults play, play can have immediate functions such as defusing social tensions and dominance relationships. Rats are an interesting case. They engage in juvenile play much more than other rodent species. Adult rats seem to exhibit novel mental capabilities, especially those involving social interactions that are not so prominent in other rodents.

When members of a play-oriented species are denied access to juvenile play, they can become dysfunctional adults. For example, rats raised in social isolation show physical and chemical deficiencies in their brains and they have behavioral abnormalities linked to impaired executive control function. They show excessive anxiety to stressful or fear-inducing situations. They over-react to benign social interactions. They are less able to coordinate movements with a partner, both in sexual and non-sexual contexts. They are less able to solve mental tasks. Similar problem are seen in monkeys deprived of juvenile play. Being raised by a surrogate mother is emotionally and intellectually devastating, but less so if the surrogate is robot-like and can interact in play-like behavior with the infant.

Juvenile play sculpts the brain to be more adaptable later in life. In modern human society, juvenile play is often obstructed by such externals as over-scheduling, too much adult supervision, and too many restrictions. The restrictions are often for reasons of safety, which is understandable in today's world. When I was a child, we had a lot more freedom to play, and in safety. It was not unusual in the summer time for a kid to leave home after breakfast and not return until supper, going alone to a park or neighbor kid's house to play unsupervised as we wished. Sadly, that is too much freedom these days. In this respect, the "good old days" really were the "good old days."

Source:

Pellis, S. M., Pellis, V. C., and Himmler, B. T. (2014). How play makes for a more adaptable brain. Ame. J. Play. 7 (1) 73-98

"Memory Medic's new book has just been released: "Improve Your Memory for a Healthy Brain." Smashwords.com

In other blog posts I have explained why sleep is good for the brain in general and memory formation in particular. Now a new discovery provides another reason for people to get enough sleep. The study examined a type of support cell in the brain, oligodendrocytes–let’s call them oligos for short. These cells wrap their membranes around nerve cells to form what is called myelin, which forms an electrical insulation in a way that speeds up the propagation of nerve impulses through neural networks. You may have heard about oligos in reading about multiple sclerosis, a disease that impairs nerve communication because oligos die and the myelin insulation degrades.

Speed of transmission is important–it influences IQ for example. As you know from buying a new computer, the faster processor speed gives it new capabilities your old clunker could not do. A similar idea applies to the brain.

Anyway, this new study, from the University of Wisconsin, focused on oligos because other research had shown that sleep promoted the expression of several genes that are involved in synthesis of cell membranes in general and those in oligos in particular. Unlike neurons, oligos die, and are replaced in the brain. Thus, anything that affects their turnover is important for brain function. Sleep has been implicated in this turnover because a common neurotransmitter in the brain, glutamate, is known to increase in wakefulness and decline during sleep. Glutamate  suppresses maturation of oligo precursor cells into formation of myelin insulation.

In this particular study, investigators examined a genome-wide profile of oligo gene expression in mice after a 6-7 hour periods of sleep or spontaneous wakefulness, or four hours of forced wakefulness (sleep deprivation). They found that 357 genes were expressed differently, depending on the time of day, in response to normal daily rhythms. More dramatic was the observation that 714 genes changed expression in conjunction with the sleep/wakefulness cycle, independent of the time of day. Of these genes, 310 were “sleep” genes that were selectively activated during sleep.

Many of the sleep genes contribute to maturation of oligos into myelin. In follow up experiments, mice were injected with a radiolabeled tag that marks the birth of new cells. Injection occurred eight hours before mice spent a long period of either of wakefulness or sleep. The number of newly born oligos was almost double in the sleep group compared to the wake group. More detailed analysis showed that this increase was specifically correlated with the amount of REM sleep (dream sleep in humans).

This REM effect may have particular importance in humans. Most REM sleep occurs in the early morning hours and only after substantial time has been spent in non-REM stages of sleep. Thus, cutting a night’s sleep short by getting up early may decrease the amount of REM time and thus the beneficial effects on oligo proliferation. So don’t feel guilty about “sleeping in” from time to time.

We might also think about how these findings could have special relevance to children, whose brains are incompletely myelinated. Getting children up early in the morning to start school at 8 AM may not be such a good idea. Until school districts get around to changing school hours, you might tell you kids about my learning and memory improvement e-book, Better Grades, Less Effort, available at Smashwords.com.

Source:

Bellesi, M., et al. (2013) Effects of sleep and wake on oligodendrocytes and their precursors. J. Neuroscience. 33 (36), 14288-14300.