Book 1 Reading and Speaking (1108795), страница 9
Текст из файла (страница 9)
That’s food forthought.It’s not just what you eat that affects the brain. It’s also how much. Research has shown that laboratoryanimals fed calorie-restricted diets—anywhere from 25 to 50 percent less than normal—live longer than otheranimals do. And it turns out they also have improved brain function, performing better on tests of memory andcoordination.
Rodents on calorie-restricted diets are also better able to resist the damage that accompaniesAlzheimer’s, Parkinson’s and Huntington’s disease.METHOD 3: STIMULANTSStimulants are substances that rev up the nervous system, increasing heart rate, blood pressure, energy,breathing and more. Caffeine is probably the most famous of the group. (It is actually the most widely used “drug”in the world.) By activating the central nervous system, caffeine boosts arousal and alertness. Although high dosesof caffeine can undoubtedly have unpleasant effects (ranging from irritability, anxiety and insomnia to the mostunpleasant of all: death in rare cases), small to moderate amounts can boost our mental functioning in waysresearchers are now measuring. One study showed that the equivalent of two cups of coffee can boost short-termmemory and reaction time. Functional MRI scans taken during the study also revealed that volunteers who hadbeen given caffeine had increased activity in the brain regions involving attention.
In addition, research suggestscaffeine can protect against age-related memory decline in older women. But try to limit yourself to fewer than 100cups a day. That much coffee contains about 10 grams of caffeine, enough to cause fatal complications.Cocaine and amphetamines are less benign. Although they work on the brain through different mechanisms,they have similar effects.
Taking them increases the release of some of the brain’s feel-good neurotransmitters—including dopamine and serotonin—and produces a rush of euphoria. They also increase alertness and energy.That all sounds pretty good, but cocaine and amphetamines are extremely addictive drugs and in high doses theycan cause psychosis and withdrawal. The withdrawal symptoms are nasty and can lead to depression, the oppositeof that euphoric feeling. And of course, an overdose can kill you.METHOD 4: VIDEO GAMESVideo games could save your life. Surgeons who spend at least a few hours a week playing video gamesmake one-third fewer errors in the operating room than nongaming doctors do. Indeed, research has shown thatvideo games can improve mental dexterity, while boosting hand-eye coordination, depth perception and patternrecognition.
Gamers also have better attention spans and information-processing skills than the average Joe has.When nongamers agree to spend a week playing video games (in the name of science, of course), their visualperception skills improve. And strike your notions of gamers as outcasts: one researcher found that white-collarprofessionals who play video games are more confident and social.Of course, we cannot talk about the effects of video games without mentioning the popular theory that theyare responsible for increasing real-world violence. A number of studies have reinforced this link. Young men whoplay a lot of violent video games have brains that are less responsive to graphic images, suggesting that thesegamers have become desensitized to such depictions. Another study revealed that gamers had patterns of brainactivity consistent with aggression while playing first-person shooter games.
This does not necessarily mean theseplayers will actually be violent in real life. The connections are worth exploring, but so far the data do not supportthe idea that the rise of video games is responsible for increased youth violence.23METHOD 5: MUSICWhen you turn on Queen’s Greatest Hits, the auditory cortex analyzes the many components of the music:volume, pitch, timbre, melody and rhythm. But there’s more to music’s interaction with the brain than just the rawsound.
Music can also activate your brain’s reward centers and depress activity in the amygdala, reducing fear andother negative emotions. A highly publicized study suggested that listening to Mozart could boost cognitiveperformance, inspiring parents everywhere to go out and buy classical CDs for their children.
The idea of a “Mozarteffect” remains popular, but the original study has been somewhat discredited, and any intellectual boost thatcomes from listening to music seems to be tiny and temporary. Nevertheless, music does seem to possess somegood vibrations. It can treat anxiety and insomnia, lower blood pressure, soothe patients with dementia, and helppremature babies to gain weight and leave the hospital sooner.Music training can bolster the brain.
The motor cortex, cerebellum and corpus callosum are all bigger inmusicians than in nonmusicians. And string players have more of their sensory cortices devoted to their fingersthan do those who don’t play the instruments. There is no agreement yet on whether musical training makes yousmarter, but some studies have indeed shown that music lessons can improve the spatial abilities of young kids.METHOD 6: MEDITATIONMeditation, or the turning of the mind inward for contemplation and relaxation, seems to help all types ofconditions—anxiety disorders, sure, but it can also reduce pain and treat high blood pressure, asthma, insomnia,diabetes, depression and even skin conditions. And regular meditators say they feel more at ease and morecreative than nonmeditators do.
Researchers are now illuminating the actual brain changes caused by meditationby sticking meditators into brain-imaging machines. For one, although the brain’s cells typically fire at all differenttimes, during meditation they fire in synchrony. Expert meditators also show spikes of brain activity in the leftprefrontal cortex, an area of the brain that has generally been associated with positive emotions.
And those whohad the most activity in this area during meditation also had big boosts in immune system functioning.Meditation can increase the thickness of the cerebral cortex, particularly in regions associated with attentionand sensation. (The growth does not seem to result from the cortex growing new neurons, though—it appears thatthe neurons already there make more connections, the number of support cells increases, and blood vessels in thatarea get bigger.) (From Scientific American, February, 2009)Exercise 4. Do you agree with the recommendations given? Comment on each method suggested.Exercise 5. Do you know any other methods that can help you to increase brainpower?24Unit 7. SleepSleep covers a Man all over, Thoughts and all,like a Cloak; ’tis Meat for the Hungry, Drink forthe Thirsty, Heat for the Cold, and Cold for theHot.Miguel de Cervantes Don QuixoteIntroduction.Sleep remains one of the great mysteries of modern neuroscience.
We spend nearly one-third of our livesasleep, but the function of sleep still is not known. Fortunately, over the last few years researchers have madegreat headway in understanding some of the brain circuitry that controls wake-sleep states. Scientists nowrecognize that sleep consists of several different stages; that the choreography of a night’s sleep involves theinterplay of these stages, a process that depends upon a complex switching mechanism; and that the sleep stagesare accompanied by daily rhythms in bodily hormones, body temperature and other functions.Sleep disorders are among the nation’s most common health problems, affecting up to 70 million people,most of whom are undiagnosed and untreated. These disorders are one of the least recognized sources ofdisease, disability and even death, costing an estimated $100 billion annually in lost productivity, medical bills andindustrial accidents.
Research holds the promise for devising new treatments to allow millions of people to get agood night’s sleep.Exercise 1. What do you know about sleep?1. What is sleep? What processes take place in human organism during sleep?2. What processes take place in the human brain during sleep?3. How long does sleep last? What stages does it include?4. What sleep disorders do you know?5. Are you an early bird or a night owl? What other sleep habits do you have?Exercise 2.
Is sleep primarily to benefit the body or the mind? Read the following text to find the answer.Why Do We Sleep?By C. Claiborne Ray“Sleep has many functions, and most of us think the main functions are not for the body but for the brain,”said Dr. Arthur Spielman, a sleep expert at City College of New York. “But,” he added, “you are talking to a brainscientist, and it depends on whom you ask.’’The reason sleep occurs in the first place is tied to both mental and physiological cycles that evolved on aplanet with a 24-hour cycle of light and dark, Dr. Spielman said. The internal biological clocks that developed inliving things, from single cells to humans, allow them to anticipate the transitions from light to dark and from dark tolight, so that they are ready for the functions appropriate to light, like metabolism and photosynthesis, and for thosesuited to darkness.
“A physiologist might say sleep was to avoid wasting metabolic energy in the dark,’’ he said.“But a brain scientist would say that glycogen, the only fuel for the brain, is depleted during waking and restoredduring sleep.”Sleep is useful for restoring particular parts of the brain that are quiet during sleep and return to functioningduring waking, like the areas involved in attention, alertness and memory. Sleep is also important for regulating thetiming of hormones under the control of the brain, Dr. Spielman said, like cortisol, the stress-response hormone,which is suppressed at the beginning of sleep and ramps up in anticipation of waking, and growth hormone, whichis secreted at night during sleep characterized by slow brain waves.
(August 15, 2006 NY Times)Exercise 3. Read the chapter about sleep taken from the book Brain Facts: a Primer on the Brain andNervous System, 2002 to check your answers in Exercise 1.The Stuff of SleepSleep appears to be a passive and restful time when the brain is less active. In fact, this state actuallyinvolves a highly active and well-scripted interplay of brain circuits to produce the stages of sleeping.The stages of sleep were discovered in the 1950s in experiments examining the human brain waves orelectroencephalogram (EEG) during sleep. Researchers also measured movements of the eyes and the limbsduring sleep. They found that over the course of the first hour or so of sleep each night, the brain progressesthrough a series of stages during which the brain waves progressively slow down. The period of slow wave sleep isaccompanied by relaxation of the muscles and the eyes.
Heart rate, blood pressure and body temperature all fall. Ifawakened at this time, most people recall only a feeling or image, not an active dream.Over the next half hour or so, the brain emerges from the deep slow wave sleep as the EEG waves becomeprogressively faster. Similar to during waking, rapid eye movements emerge, but the body’s muscles becomealmost completely paralyzed (only the muscles that allow breathing remain active). This state is often called rapid25eye movement (REM) sleep. During REM sleep, there is active dreaming. Heart rate, blood pressure and bodytemperature become much more variable. The first REM period usually lasts ten to 15 minutes.Over the course of the night, these alternative cycles of slow wave and REM sleep alternate, with the slowwave sleep becoming less deep, and the REM periods more prolonged, until waking occurs.Over the course of a lifetime, the pattern of sleep cycles changes.
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