Sleep & Wakefulness

• Sleep experts recommend that adults get seven to nine hours of sleep but in the US, adults typically get about 6.8 hours of sleep.
• Endogenous means being generated by the body regardless of environment which is naturally occuring
• Circannual Rhythm prepares animals for seasonal changes even when caged without cues to the season
• Circadian Rhythm is a rhythm that last a day and are synchronized such as wakefulness and sleep, hormone, Frequency of eating, body temperature.
• Biologic Clock or Sense of Time - Duration for humans is between 24-25 hours, it is insensitive to most interference such as food and water deprivation
• Humans and other animals have an internal biological clock called the circadian rhythm
• Circadian Rhythm patterns vary over approximately a 24 hour cycle and occur even in the absence of normal cues about whether it is day or night.
• Suprachiasmatic Nucleus is an area of hypothalamus that sets the circadian rhythm
• Neurons produce Circadian rhythm tissue culture, genes interact with proteins Per and Tim to generate rhythm
• Mutant per gene accelerated biological clock, Pineal gland releases melatonin 2 hours before bed time
• Once the Suprachiasmatic Nucleus rhythms are damaged, rhythms are less consistent, not synchronized to light and dark patterns
• The sun activates proteins in the retina of our eyes and will signal Suprachiasmatic Nucleus, SCN cluster of neurons in the hypothalamus that governs the timing of circadian rhythms
• Melatonin is a hormone of the pineal gland that produces sleepiness
• Bright light decreases production of melatonin; decreases light increases melatonin
• Frequencies are numbers of wave per seconds
• Amplitudes is heights or an index strength
• Brain waves are rough indicators of the activity of large numbers of neuroms
• Volts is the unit of measurements for strength or energy of brain waves
• Alpha waves are rapid low amplitude brain waves that have been linked to feelings of relaxation
• Rapid Eye Movement or (REM) sleep refers to a stage of sleep characterized by rapid eye movements, which have been linked to dreaming
• Theta waves or slow brain waves produced during the hypnagogic state (6-8 cycles per second)
• Delta waves (strong) are slow brain waves usually emitted during stage 4 sleep
• The use of EEG shows variation in brain waves which determine different stages of sleep.
• During an 8 hour period, people typically progress through all 5 full cycles, each cycle lasts about 90 minutes
• When awake, brain waves show a high frequency, low amplitude pattern
• NREM or (non-rapid eye movement) sleep involves increasing bodily relaxation slower EEG activity occurs
• The heart rate and respiration are slower during NREM
• In NREM brain waves are of low amplitude and are fast with mixed frequencies
• People become more difficult to awaken as they progress through the four stages of NREM sleep.
• Sleepers take about 30 to 40 minutes to go through four stages of NREM sleep.
• REM sleep is also called paradoxical sleep becauss the EEG patterns observed suggest a level of arousalmsimilar to that of the waking state
• REM is difficult to distinguish from being awake on the basis of the physiological measures
• REM helps consolidate memories like a Memory Storage
• Brain areas that are active during the learning of the task become active again during sleep.
• Performance on tasks usually improves if you test someone a day after they've learned the task
• Restoration Theory claims that the body wears out during the day and sleep is necessary to put it back in shape
• Adaptive theory suggests that sleep emerged in evolution to preserve energy and protect during the time of day when there is considerable danger