Chapter 10 - Sleep

• biological rhythm


  a regular fluctuation in any living process
• circadian rhythym


  a pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period
• infradian


  referring to a rhythmic biological event with a period longer than a day
• ultradian


  referring to a rhythmic biological event with a period shorter than a day
• free-running


  referring to rhythm of behavior shown by an animal depreived of external cues about time of day
• period


  the interval of time between two similar points of successive cycles
• phase shift


  a shift in the activity of a biological rhythm, typically provided by a synchronizing environmental stimulus such as light
• entrainment


  the process of synchronizing a biological rhythm to an environmental stimulus
• zeitgeber


  literally "time giver"; the stimulus the entrains circadian rhythms
• suprachiasmatic nucleus (SCN)


  a small region of the hypothalamus above the optic chiasm that is the location of the circadian clock
• melatonin


  a mine hormone that is secreted by the pineal gland at night, thereby signaling day length to the brain
• retinohypothalamic pathway


  the route by which specialized retinal ganglion cells send their axons to the suprachiasmatic nuclei
• melaniospin


  a photopigment found in those retinal ganglion cells that project to the suprachiasmatic nucleus
• electroencephalography


  the recording of gross electrical activity of the brain via large electrodes placed on the scalp
• rapid-eye-movement sleep


  a stage of sleep characterized by small-amplitude, fast EEG waves, no postural tension, and rapid eye movements
• non-REM sleep


  sleep, divided into stages 1-3, that is defined by the presence of distinctive EEGT activity that differs from that seen in REM sleep
• desynchronized EEG


  a pattern of EEG activity comprising a mix of many different high-frequencies with low amplitude
• alpha rhythm


  a brain potential of 8-12 Hz that occurs during relaxed wakefulness
• vertex spike


  a sharp-wave EEG pattern that is seen during stage 1 sleep
• stage 2 sleep


  a stage of sleep that is defined by bursts of EEG waves called sleep spindles
• sleep spindle


  a characteristic 12-14 Hz wave in the EEG of a person said to be in stage 2 sleep
• K complex


  a sharm, negatice EEG potential that is seen in stage 2 sleep
• stage 3 sleep


  a stage of non-REM sleep that is defined by the presence of large-amplitude, slow delta waves
• delta wave


  the slowest type of EEG wave, about 1 per second, characteristic of stage 3 sleep
• nightmare


  a long, frightening dream that awakens the sleeper from REM sleep
• night terror


  a sudden arousal from stage 3 sleep that is marked by intense fear and autonomic activation
• sleep recovery


  the process of sleeping more than normally after a period of sleep deprivation, as though in compensation
• fatal familial insomnia


  an inherited disease that causes people in middle age to stop sleeping, which after a few months results in death
• ecological niche


  the unique assortment of environmental opportunities and challenges to which each organism is adapted
• isolated brain


  a experimental preparation in which an animal's brainstem has been separated from the spinal cord by a cut below the medulla
• isolated forebrain


  an experimental preparation in which an animal's nervous system has been cut in the upper midbrain, dividing the forebrain from the brainstem
• basal forebrain


  a ventral region in the forebrain that has been implicated in sleep
• tuberomammilary nucleus


  a region of the basal hypothalamus, near the pituitary stalk, that plays a role in generating slow wave sleep
• general anesthetic


  a drug that renders an individual unconscious
• reticular forebrain


  an extensive region of the brainstem that is involved in arousal
• locus coeruleus


  a small nucleus in the brainstem whose neurons produce norepinephrine and modulate large areas of the forebrain
• narcolepsy


  a disorder the involves frequent, intense episodes of sleep, which last from 5 to 30 minutes and can occur anytime during the usual waking hours
• cataplexy


  sudden loss of muscle tone, leading to collapse of the body without loss of consciousness
• orexin/hypocretin


  a neuropeptide produced in the hypothalamus that is involved in switching between sleep states, in narcolepsy, and in the control of appetite
• sleep paralysis


  a state, during the transition to or from sleep, in which the ability to move or talk is temporarily lost