Brain development Memory / cognition / long term potential Immunity Conservation energy Repair & Restoration
Regular sleep time Proper sleep environment Stimulation control Avoidance of time in bed worrying Avoidance of poorly timed alcohol and caffeine Regular exercise but not within 3 hours of bedtime Wind-down time Late-night high-tryptophan snack
Human circadian clock generates a rhythm slightly longer than 24 hours when it has no external cue to set it. Most people can adjust to 23- or 25- hour day but not to a 22- or 28- hour day. Bright light late in the day can lengthen the circadian rhythm.
Duration of sleep Circadian rhythm Circadian clock Zeitgeber Circannual rhythm The purpose of the circadian rhythm is to keep our internal workings in phase with the outside world. Light is critical for periodically resetting our circadian rhythms. A zeitgeber is a term used to describe any stimulus that resets the circadian rhythms. Exercise, noise, meals, and temperature are others zeitgebers.
Mechanisms of the circadian rhythms include the following: The Suprachiasmatic nucleus. Genes that produce certain proteins. Melatonin levels.
Physiological pathway of the biological clock: Light levels retina suprachiasmatic nucleus of hypothalamus pineal gland secretion of melatonin
The suprachiasmatic nucleus (SCN) is part of the hypothalamus and the main control center of the circadian rhythms of sleep and temperature.
Meditation = practices that train attention to heighten awareness and bring mental processes under greater voluntary control Yoga, Zen, transcendental meditation (TM) Potential physiological benefits Similar to effective relaxation procedures
EEG:- rhythmic alpha waves (8-12Hz) // only if the eyes are closed - beta waves (20-30Hz) EOG:- eye movement (observation process) EMG:- continual tonically activity of muscles
Loss of eye blink Attenuation of Alpha rhythm Slow rolling eye movements Fronto central Theta activity Increased Beta activity Vertex waves
EEG:- the absence of alpha activity - Vertex sharp waves EOG: - slow eye movement EMG:- relatively lower amplitude
Sleep spindles Brief, 12 – 16 Hz, synchronous bursts of activity, usually maximal in the central, or less commonly frontal, regions K complexes Often accompany sleep spindles. A sharp negative wave followed by a high-voltage slower wave Vertex waves Named for tendency to phase reverse in central regions. Sharp waves May occur in trains K complexs & Vertex waves may result from brief sleep disturbances
EEG:- sleep spindles (oscillating with the frequency between Hz) - K-complexes (high voltage, sharp rising and sharp falling wave) - relatively low voltage mixed frequency EOG:- the absence eye movements EMG:- constant tonic activity
> 20 % but < 50 % of the background rhythm is Delta activity
EEG:- consists of high-voltage (>=75uV) - slow delta activity (<=2 Hz) // electrodes Fpz-Cz or Pz-Oz EOG:- the absence eye movement - delta waves from EEG EMG:- low tonic activities
> 50% of the background rhythm is Delta activity
Bursts of rapid eye movement Loss of muscle activity “ Desynchronization ” of the background rhythm. The predominant delta rhythm of slow wave ( stage III & IV ) sleep is replaced by faster frequency ( beta and theta ) rhythms normally seen during the wakeful state. Sawtooth waves
EEG:- relatively low voltage - mixed frequency EOG:- contains rapid eye movements EMG:- tonically suppressed ( Sleep Paralysis )
Insomnia – difficulty falling or staying asleep Narcolepsy – falling asleep uncontrollably Sleep Apnea – reflexive gasping for air that awakens Nightmares – anxiety arousing dreams – REM Night Terrors – intense arousal and panic – NREM Somnambulism – sleepwalking