Intro short cards Flashcards
The absolute threshold (абсолютный порог)
it is the minimum amount of a stimulus that is needed for a person to notice its presence (минимальное количество стимула, которое необходимо для того, чтобы человек заметил его присутствие). For example, the absolute threshold of vision is the minimum amount of light that a person can see in a dark room (абсолютный порог зрения - это минимальное количество света, которое человек может видеть в темной комнате), while the absolute threshold of hearing is the minimum volume of sound that a person can hear in a quiet environment.
The relative threshold (относительный порог)
The relative threshold refers to the minimum amount of stimulation required for a neuron to become activated and send a signal to other neurons in the brain (относится к минимальному количеству стимуляции, необходимой для того, чтобы нейрон активизировался и послал сигнал другим нейронам мозга).
In the brain, neurons have a threshold that needs to be surpassed (превысить) in order for them to “fire” (сработали) and send a signal to other neurons. This threshold can be influenced by strength of the input signal and the state of the neuron at the time of stimulation.
The absolute refractory period (Абсолютный рефрактерный период)
The absolute refractory period is a time period after a neuron fires an action potential - sends a signal (запускает потенциал действия - посылает сигнал) when it is unable to fire another action potential (не в состоянии запустить другой потенциал действия), no matter how strong the incoming signal is (независимо от того, насколько силен входящий сигнал). It’s like a rest period for the neuron, during which it cannot respond to any new signals. This period is lasting 1-2 milliseconds.
The relative refractory period (относительный рефрактерный период)
The relative refractory period is a brief time period after a neuron fires an action potential - sends a signal -(активирует потенциал действия - посылает сигнал) during which it is more difficult to fire another action potential, even if an incoming signal is received (аже если получен входящий сигнал). It’s like a recovery period for the neuron, during which it needs a stronger-than-usual incoming signal to fire again (требуется более сильный, чем обычно, входящий сигнал, чтобы снова сработать). This period is longer than the absolute refractory period and lasting 5 to 15 milliseconds. After this period, the neuron’s threshold for firing returns to normal and it can fire another action potential in response to a normal incoming signal (порог срабатывания нейрона возвращается к норме, и он может активировать другой потенциал действия в ответ на обычный входящий сигнал).
Sleep
About every 90 minutes, we cycle through distinct sleep stages (каждые 90 минут мы проходим различные стадии сна).
REM sleep rapid eye movement sleep - a recurring (повторяющаяся) sleep stage during which vivid (яркие) dreams occur. Also known as paradoxical (пародоксальный) sleep, because the muscles are relaxed (except for minor twitches-незначительных подергиваний) but other body systems are active.
As the hour grows late (становится поздно), you feel sleepy and yawn in response to reduced brain metabolism (снижение метаболизма в могзе).
Wave patterns
alpha waves the relatively slow brain waves of a relaxed, awake state (относительно медленные мозговые волны расслабленного, бодрствующего состояния).
delta waves the large, slow brain waves associated with deep sleep.(большие, медленные мозговые волны, связанные с глубоким сном).
During this brief NREM-1 sleep you may experience fantastic images like hallucinations—sensory experiences that occur without a sensory stimulus. You may have a sensation of falling (at which moment your body may suddenly jerk-дернуться) or of floating weightlessly (невесомого парения). These hypnagogic sensations may later be included into your memories.
You then relax more deeply and begin about 20 minutes of NREM-2 sleep, with its periodic sleep spindles—bursts (всплесками ) of rapid (быстрой), rhythmic brain-wave activity. Although you could still be awakened (разбужен) without too much difficulty, you are now clearly asleep. In NREM-2 you’ll spend about half your night.
REM Sleep (фаза быстрого сна)
happens in an hour after you first fall asleep. For about 10 minutes, your brain waves become rapid and saw-toothed (пилообразными). During REM sleep heart rate rises, breathing becomes rapid and irregular, every half-minute closed eyes dart around in momentary bursts of activity (бегают по сторонам в кратковременных вспышках активности). Dreams aren’t real, but REM sleep tricks (обманывает) your brain into responding as if you are actually watching a real scene.
People pass through a multi stage sleep cycle (многоступенчатый цикл сна) several times each night, with the periods of deep sleep diminishing (уменьшаются) and REM sleep periods increasing in duration. As people age, sleep becomes more fragile, with awakenings (пробуждения) common among older adults.
During REM sleep, brain’s motor cortex is active, but brainstem blocks its messages. This leaves your muscles relaxed, so much so that, except for an occasional (случайных) finger, toe, or facial twitch, you are essentially paralyzed. Moreover, you cannot easily be awakened.
As the night goes on (с течением ночи), deep NREM-3 sleep becomes shorter and disappears, and REM and NREM-2 sleep periods get longer. By morning (к утру), we have spent some 100 minutes in REM sleep. We spend about 600 hours a year experiencing some 1500 dreams, or more than 100,000 dreams over a lifetime.
When REM starts, snoring (храп) stops.
sleep stages
REM, NREM-1, NREM-2, NREM-3;
normally we move through NREM-1, then NREM-2, then NREM-3, then back up
through NREM-2 before we experience REM sleep.
- NREM-1 - fleeting images (мимолетные образы)
- NREM-3 - minimal awareness
- REM - story-like dream (сон, похожий на историю)
NREM - Non-Rapid Eye Movement (небыстрое движение глаз).
NREM-1: This is the stage of sleep when you’re drifting off (начинаем дремать), and your body is starting to relax. It’s a light sleep stage where you can be easily awakened, and you may experience hypnic jerks or sudden muscle contractions (сокращения).
NREM-2: This is a deeper stage of sleep, where brain activity slows down, and the body temperature drops (падает). the brain is processing (обрабатывает) memories and knowledge.
NREM-3: This is the deepest stage of sleep - slow-wave sleep. slow brain waves, body repairs and regenerates tissues, strengthens the immune system, and releases growth hormones.
What Affects Our Sleep Patterns?
Sleep patterns (режим сна) are genetically and culturally influenced.
Bright light tweaks (настраивает) the circadian clock by activating light-sensitive retinal proteins (светочувствительные белки сетчатки). These proteins control the circadian clock by triggering signals to the brain’s suprachiasmatic nucleus (SCN)—a pair of grain-of-rice-sized, 10,000-cell clusters in the hypothalamus (посылая сигналы в супрахиазматическое ядро мозга (SCN) — пару кластеров размером с рисовое зернышко, состоящих из 10 000 клеток в гипоталамусе). The SCN causes the brain’s pineal gland (шишковидную железу) to decrease its production of the sleep-inducing (снижать выработку вызывающего сон гормона мелатонина) hormone melatonin in the morning and to increase it in the evening. At night, the SCN quiets down, allowing the pineal gland to release melatonin into the bloodstream (кровоток).
Night-shift workers (работники ночной смены) become moreolnikely (повышается вероятность) to develop fatigue, stomach problems, heart disease, and, for women breast cancer.
Sleep’s functions
- Sleep has survival value.
- Sleep helps restore the immune system and repair brain tissue.
- Sleep gives resting neurons time to repair themselves, while pruning or weakening unused connections (сокращая или ослабляя неиспользуемые связи).
- sleep consolidates our memories by replaying recent learning and strengthening neural connections (воспроизводя недавнее обучение и укрепляя нейронные связи). It reactivates recent experiences stored in the hippocampus and shifts them for permanent storage elsewhere in the cortex (перемещает их для постоянного хранения в другое место коры головного мозга).
- Sleep feeds creative thinking.
- Sleep supports growth. During slow-wave sleep (медленного сна), which occurs mostly in the first half of a night’s sleep, the pituitary gland releases a growth hormone that is necessary for muscle development. REM sleep and NREM-2 sleep—which occur mostly in the final hours — also help strengthen the neural connections that build enduring (устойчивые) memories, including the “muscle memories”.
Effects of Sleep Loss
Sleep deprivation:
1. increases ghrelin, a hunger-arousing hormone, and decreases leptin - hunger- suppressing hormone
2. decreases metabolic rate, a gauge (показатель) of energy use
3. increases production of cortisol, a stress hormone that stimulates the body to make fat.
4. enhances limbic brain responses to the mere sight of food (усиливает реакции лимбической системы мозга на простой вид пищи)
5. decreases cortical responses that help us resist temptation (кортикальные реакции, которые помогают нам сопротивляться искушению).
6. increases appetite and eating; our tired brain finds fatty foods more enticing (привлекательной) - risk of obesity
7. can suppress immune cells that battle viral (вирусными) infections and cancer.
8. slows reactions and increases errors on visual attention tasks similar to those involved in screening airport baggage, performing surgery, and reading X-rays Slow responses can also spell disaster driving
9. Increases risk of high blood pressure
10. muscles. reduces strength; slower reaction time and motor learning
11. increases inflammation and arthritis
12. increases risk of depression
13. decreases ability to focus attention and store memories.
sleep disorders
- insomnia
- narcolepsy
- sleep apnea
- night terrors
- Sleepwalking and sleeptalking
insomnia
recurring problems in falling or staying asleep.
1 in 10 adults; 1 in
4 older adults
Ongoing (постоянные) difficulty falling or staying asleep.
Effects:
1. Chronic tiredness. 2. Reliance (зависимость) on sleeping pills and alcohol, which reduce REM sleep and lead to tolerance—a state (состояние) in which increasing doses are needed to produce an effect.
Narcolepsy
narcolepsy - a sleep disorder characterized by uncontrollable sleep attacks (внезапным засыпанием).
The sufferer may lapse directly into REM sleep (впасть в фазу быстрого сна), often at inopportune times.
1 in 2000 adults.
Sudden attacks of overwhelming sleepiness (непреодолимая сонливость).
Narcolepsy attacks last less than 5 minutes, but they can happen at the worst and most emotional times.
