Chapter 14: Biological Rhythms, Sleep, and Dreaming Flashcards
Circadian Rhythms
are functions of a living organism that display a rhythm of about 24 hours
Rhythms may be…
behavioral, physiological, or biochemical
Diurnal
active during the light
Nocturnal
active during the dark
Infradian Rhythms
more than > 24 hours, i.e.(monthly cycles)
Ultradian Rhythms
less than < 24 hour biological rhythms with a shorter period and higher frequency than circadian rhythms
Circadian Rhythms
~ 24-hour cycle that includes physiological and behavioral rhythms like sleeping
Circannual Rhythms
~1 year rhythms, hibernation, do not depend on light/dark cycle
Free-Running
animal maintains its own cycle without external cues
Period
time between two similar points of successive cycles; may not be exactly 24 hours
Phase Shift
shift in activity in response a synchronizing stimulus, such as light
Entrainment
is the process of shifting the rhythm
Zeitgeber
cue that an animal uses to synchronize with the environment
Endogenous Clock
circadian rhythms are generated by this
- enables animals to anticipate events and helps with survival
Suprachiasmatic Nucleus (SCN)
where is biological clock is, and is above the optic chiasm in the hypothalamus
- circadian rhythms are disrupted in animals with SCN lesions
- Isolated SCN neurons can maintain electrical activity synchronized to be previous light cycle
Pineal Gland
located at the center of the brain and is sensitive to light
Retinohypothalamic Pathway
in mammals, light information goes from the eye to the SCN via this pathway
Melanopsin
a special photopigment, that makes them sensitive to light, especially blue light. Most of these retinal ganglion cells contain melanopsin
SCN cells make two proteins:
Clock and Cycle
Dimer
Clock and Cycle bind together to form this
How does light entrain the molecular clock in flies
light reaches the brain directly and degrades the Cry protein, synchronizing the molecular clock
How does light entrain the molecular clock in mammals
retinal ganglion cells detect light and release glutamate in the SCN
Tau Mutations
the period is shorter than normal
Double Clock
mutants are severely arrhythmic
Infradian Biological Rhythms
longer than a day, such as reproductive cycles
Circannual Clock
biological process that occurs in living creatures over the period of approximately one year.
Electroencephalography (EEG)
records electrical activity in the brain
Electro-oculography (EOG)
records eye movements
Electromyography (EMG)
records muscle activity
Beta Activity or Desynchronized EEG
EEG pattern of activity in an awake person that contains many frequencies
Non-REM sleep (NREM)
is divided into three stages that have characteristic activity patterns
Stage 3 (NREM3)
slow wave sleep
Slow Wave Sleep
defined by large-amplitude, very slow delta waves
Rapid-eye-movement sleep (REM)
EEG activity is like an awake person, but muscles are relaxed and limp—brainstem regions are profoundly inhibiting motor neurons
Number of Normal Sleep Cycles:
4 to 5 cycles of sleep stages
Nightmares
ling frightening dreams that awaken the sleeper from REM sleep
Night Terrors
sudden arousals from NREM sleep, marked by fear and autonomic activity
Sleep Deprivation
causes increased irritability, difficulty concentrating, episodes of disorientation
Fatal Familial Insomnia
is an inherited disease where in midlife, people stop sleeping and dies 7-24 months after the onset of insomnia. Autopsy shows degeneration in the cortex and the thalamus.
Sleep Recovery
process of sleeping more than normal after a period of deprivation
- Night 1- Stage 3 sleep is increased, usually at the expense of stage 2 sleep
- Night 2- most recovery of REM sleep, which is more intense than normal with more rapid eye movements
One role of sleep is to conserve energy:
Muscular tension, heart rate, blood pressure, temperature, and respiration rate are all reduced.
Ecological Niche
the unique assortment of environmental opportunities and challenges to which each organism is adapted
General Anesthetics
cause unconsciousness, produce slow waves in EEG that resembles SWS
Isolated Brain
made by an incision between the medulla and the spinal cord. Results show that wakefulness, SWS, and REM sleep are all mediated by networks in the brain
Isolated Forebrain
made by an incision in the midbrain: electrical activity in the forebrain showed constant SWS but not REM
The constant SWS activity in the forebrain
is generated by the:
Basal Forebrain
Neurons in this region become active at sleep onset and release GABA, which suppresses activity in the nearby
Tuberomamillary Nucleus.
Reticular Formation
activates the cortex; in the brainstem
Subcoeruleus
A specific region of the pons that triggers REM sleep
Narcolepsy
a chronic sleep disorder characterized by overwhelming daytime drowsiness and sudden attacks of sleep
Cataplexy
a sudden loss of muscle tone, leading to collapse; often in narcolepsy patients
Hypocretin
regulates sleep and arousal states
Sleep Paralysis
a brief inability to talk or move just before falling asleep or just after waking up
- May happen when the subcoeruleus continues to impose paralysis for a short while after the person awakens from a REM
Sleep Enuresis
bed-wetting
Somnambulism
sleep walking
REM Behavior Disorder (RBD):
characterized by organized behavior from an asleep person. Usually begins after age 50 and is often followed by beginning symptoms of Parkinson’s disease and dementia
Paradoxical Insmonia
people report insomnia even when EEG indicates they were asleep
Sleep-Onset Insomnia
difficulty falling asleep; caused by situational factors, such as shift work or jet lag
Sleep-Maintenance Insomnia
difficulty staying asleep; may be caused by drugs or neurological factors
Sleep Apnea
breathing stops or slows down; blood oxygen drops rapidly
Obstructive Apnea
progressive relaxation of muscles. A continuous positive airway pressure, or CPAP, machine prevents collapse of airways
Central Apnea
changes in pacemaker respiratory neurons of the brainstem
Sudden Infant Death Syndrome (SIDS)
sleep apnea resulting from immature respiratory pacemaker systems or arousal mechanisms
Sleep Hygiene
habits that promote healthy sleep
