Consciousness, Sleep, and Circadian Rhythms (6B) - Psych & Soc

1. What is the typical direction of heart rate and respiration during NREM sleep?

   They generally decrease and become more regular. Body conserves energy with slower, steadier vitals.

2. What EEG pattern defines NREM stage 2 (N2) sleep?

   Sleep spindles and K-complexes. Spindles are 12-14 Hz bursts; K-complexes are sharp wave deflections.

3. What is the reticular activating system (RAS) primarily responsible for?

   Arousal and regulating the sleep–wake transition. Located in the brainstem, it maintains wakefulness and alertness.

4. Which sleep stage is characterized by rapid eye movements and vivid dreaming?

   REM sleep. Paradoxical sleep with high brain activity but paralyzed voluntary muscles.

5. What hormone does the pineal gland secrete to promote sleepiness, especially in darkness?

   Melatonin. Secreted by the pineal gland, it signals darkness to the body, facilitating the onset of sleep.

6. What is sleep latency in a sleep study context?

   Time from lights out to sleep onset. It quantifies the duration needed to transition from full wakefulness to the initial stage of sleep.

7. What term describes altered consciousness with reduced awareness and responsiveness?

   Sleep. A naturally recurring state with decreased sensory activity and inhibited muscular activity.

8. Which option best defines sleep debt?

   Cumulative sleep loss from consistently insufficient sleep. Chronic sleep deprivation accumulates like a debt.

9. What is narcolepsy, in terms of major symptoms relevant to the MCAT?

   Excessive daytime sleepiness with REM intrusion (often cataplexy). It involves abrupt REM-like states intruding into wakefulness, often triggered by emotions or sleep deprivation.

10. What is the circadian rhythm, and what is its approximate period in humans?

    Endogenous daily cycle; approximately $24$ hours. It is an internal biological clock that regulates sleep-wake cycles and other physiological processes over roughly a day.

11. Which NREM parasomnia involves walking or complex behaviors with minimal awareness?

    Sleepwalking (somnambulism). Occurs during deep NREM-3 sleep with partial arousal and amnesia.

12. Which sleep stage is most associated with sleepwalking (somnambulism)?

    NREM stage 3 (N3). Occurs during deep sleep when motor cortex remains active.

13. What is the reticular activating system (RAS) primarily responsible for?

    Arousal and wakefulness regulation. The RAS modulates sensory input to the cortex, promoting alertness and filtering irrelevant stimuli.

14. What is cataplexy, and with which disorder is it classically associated?

    Sudden loss of muscle tone; narcolepsy. Triggered by strong emotions, it reflects REM atonia occurring during wakefulness due to orexin dysfunction.

15. What is paradoxical sleep, and which stage does it correspond to?

    REM sleep: active brain with skeletal muscle atonia. It features EEG activity resembling wakefulness but with motor paralysis to prevent dream enactment.

16. Identify the two main processes in the two-process model of sleep regulation.

    Homeostatic sleep drive and circadian alerting signal. Process S builds sleep pressure; Process C promotes wakefulness.

17. Identify the neurotransmitter class that increases wakefulness and attention in the brain.

    Monoamines (for example, norepinephrine and serotonin). These neurotransmitters enhance cortical activation and arousal through projections from brainstem nuclei.

18. What is the typical direction of heart rate and respiration during REM sleep?

    More variable and often increased compared with NREM. Autonomic functions become irregular during REM's heightened brain activity.

19. During which sleep stage does sleepwalking most commonly occur?

    NREM Stage 3 (N3). Parasomnias like sleepwalking occur in deep NREM sleep.

20. Which sleep stage is defined by sleep spindles and K-complexes?

    NREM-2. These EEG features distinguish light sleep from other stages.

21. Which parasomnia involves acting out dreams due to loss of normal REM atonia?

    REM sleep behavior disorder. Failure of normal muscle paralysis allows dream enactment.

22. What is the definition of consciousness in psychology?

    Awareness of self and environment, including subjective experience. Encompasses both objective awareness and subjective experiences.

23. Which sleep disorder involves repeated breathing interruptions during sleep?

    Sleep apnea. Obstructive or central causes lead to oxygen deprivation and fragmented sleep.

24. Identify the condition caused by circadian misalignment after rapid time-zone travel.

    Jet lag. SCN remains synchronized to origin time zone, causing sleep disruption.

25. Identify the correct term for a learned association between bed cues and wakefulness in insomnia.

    Conditioned arousal (classical conditioning). Bedtime stimuli become paired with alertness through repeated associations, exacerbating sleep difficulties.

26. What is the defining feature of REM sleep behavior disorder (RBD)?

    Loss of REM atonia causing dream enactment behaviors. Failure of normal muscle paralysis during REM leads to potentially injurious physical actions mirroring dreams.

27. Which sleep disorder is marked by sudden sleep attacks and possible cataplexy?

    Narcolepsy. Caused by hypocretin/orexin deficiency affecting sleep-wake regulation.

28. What is the suprachiasmatic nucleus (SCN) and what does it regulate?

    Hypothalamic clock that regulates circadian rhythms. Located in the hypothalamus, responds to light cues via the retina.

29. What is sleep apnea, stated as the core physiological problem?

    Repeated breathing interruptions during sleep. These cessations cause oxygen desaturation and frequent arousals, leading to daytime fatigue.

30. Which sensory pathway provides the SCN with light information for entrainment?

    Retinohypothalamic tract from the retina. This pathway transmits light signals directly to the SCN, enabling synchronization of circadian rhythms with the day-night cycle.

31. Which hormone increases in darkness to promote sleepiness?

    Melatonin (from the pineal gland). Darkness triggers pineal gland to release this sleep hormone.

32. What is the reticular activating system (RAS) primarily responsible for?

    Arousal and regulation of the sleep–wake cycle. Located in the brainstem, it filters sensory information and maintains consciousness.

33. Which type of sleep apnea is caused by upper airway obstruction rather than absent drive?

    Obstructive sleep apnea. Airway collapse halts breathing despite intact central respiratory signals, common in obesity.

34. Which sleep stage is most strongly associated with vivid dreaming and rapid eye movements?

    REM sleep. Heightened brain activity during this stage facilitates dream vividness and oculomotor bursts.

35. What is REM sleep most strongly associated with?

    Vivid dreaming and rapid eye movements. Eyes move rapidly while most vivid dreams occur.

36. What is a circadian rhythm?

    An endogenous biological cycle of about 24 hours. Internal clock that persists even without external time cues.

37. Which sleep stage is most associated with vivid dreaming and muscle atonia?

    REM sleep. Paradoxical sleep with active brain but paralyzed voluntary muscles.

38. Which sleep stage is characterized by sleep spindles and K-complexes on EEG?

    NREM stage $2$ (N2). These EEG patterns signify light sleep, aiding in memory consolidation and sensory gating.

39. Which NREM stage shows the highest-amplitude, lowest-frequency delta waves?

    NREM stage $3$ (N3), slow-wave sleep. Delta waves dominate this deep sleep stage, crucial for physical restoration and growth hormone release.

40. Identify the sleep stage in which sleepwalking (somnambulism) most commonly occurs.

    NREM stage $3$ (slow-wave sleep). Parasomnias like somnambulism emerge from partial arousals in deep NREM, without full consciousness.

41. Which EEG pattern is most associated with relaxed wakefulness with eyes closed?

    Alpha waves. 8-13 Hz waves indicate a calm, restful state but not deep sleep.

42. What is insomnia, defined by the primary complaint rather than a specific cause?

    Difficulty initiating or maintaining sleep with impairment. It results in non-restorative sleep and functional deficits, often perpetuated by stress or poor habits.

43. What brain structure is the primary pacemaker of circadian rhythms?

    Suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN acts as the master clock, coordinating bodily rhythms in response to environmental cues like light.

44. What is narcolepsy characterized by?

    Excessive daytime sleepiness with sleep attacks and cataplexy. Caused by hypocretin/orexin deficiency affecting sleep-wake regulation.

45. What is the difference between consciousness and unconsciousness?

    Conscious: aware; unconscious: lacks awareness of self and surroundings. Consciousness requires awareness; unconsciousness lacks it entirely.

46. Which circadian disruption occurs after rapid travel across time zones and misaligns the SCN?

    Jet lag. Desynchronization between internal circadian clock and new time zone causes fatigue and sleep disturbances.

47. What is the key EEG difference between REM sleep and NREM sleep?

    REM: low-amplitude, high-frequency; NREM: slower waves. REM exhibits desynchronized waves similar to wakefulness, whereas NREM progresses to synchronized, high-amplitude patterns.

48. Which sleep stage is characterized by sleep spindles and K-complexes on EEG?

    NREM Stage 2 (N2). These EEG patterns distinguish N2 from other stages.

49. What is the main EEG feature of NREM stage 1 (N1) sleep?

    Theta waves. 4-7 Hz waves mark the transition from wakefulness to sleep.

50. Which condition best explains fatigue after rapid travel across time zones?

    Jet lag from circadian rhythm desynchronization. Body clock conflicts with new time zone causing fatigue.

51. What is REM atonia?

    Skeletal muscle paralysis during REM sleep. Prevents physical movement during vivid dreams.

52. What is the suprachiasmatic nucleus (SCN) and what does it regulate?

    Hypothalamic clock regulating circadian rhythms. Master clock in hypothalamus synchronizes body's 24-hour cycles.

53. Which disorder is defined by recurrent unpleasant dreams during REM sleep?

    Nightmare disorder. Distinguished from night terrors, which occur in NREM sleep.

54. Identify the sleep disorder: repeated breathing cessation during sleep with daytime sleepiness.

    Sleep apnea. Breathing stops repeatedly, causing fragmented sleep.

55. What is consciousness in psychology, in terms of awareness of self and environment?

    Awareness of internal states and external surroundings. This definition encompasses the subjective experience of thoughts, feelings, and perceptions in relation to oneself and the world.

56. What is the difference between conscious, preconscious, and unconscious processing?

    Conscious: aware; preconscious: retrievable; unconscious: inaccessible. These Freudian levels differentiate mental processes based on their accessibility to conscious awareness.

57. Which EEG pattern is most associated with alert wakefulness and active thinking?

    Beta waves. 13-30 Hz waves reflect high cortical activity during concentration.

58. What is the defining EEG characteristic of NREM stage 3 (N3) sleep?

    High-amplitude, low-frequency delta waves. Delta waves (<4 Hz) indicate deep, restorative slow-wave sleep.

59. What is melatonin's typical relationship to light exposure?

    Darkness increases melatonin; light suppresses it. Light detected by retina signals SCN to inhibit pineal melatonin release.

60. Which sleep stage is most associated with memory consolidation for procedural skills?

    REM sleep. REM strengthens motor skills and procedural memories.

61. Which sleep disorder involves difficulty sleeping at night due to misalignment from night work?

    Shift work sleep disorder. Non-traditional schedules misalign work with natural sleep times, impairing alertness and health.

62. Which hormone from the pineal gland rises in darkness to promote sleepiness?

    Melatonin. Secretion peaks at night, signaling body to prepare for sleep.

63. What neurotransmitter is classically associated with wakefulness and arousal?

    Norepinephrine (notably from the locus coeruleus). Locus coeruleus releases NE to maintain alertness.

64. What is the defining muscle activity state during REM sleep?

    Skeletal muscle atonia. Temporary paralysis prevents physical acting out of dreams.

65. What is sleep latency?

    Time from attempting sleep to sleep onset. Measures how quickly someone falls asleep.

66. What is the main environmental cue (zeitgeber) that entrains circadian rhythms?

    Light (especially morning light). Light exposure resets the biological clock daily.

67. Identify the sleep disorder: sudden sleep attacks with possible cataplexy.

    Narcolepsy. Loss of hypocretin causes sudden sleep and muscle weakness.

68. Which sleep stage has the highest arousal threshold and is associated with delta waves?

    NREM-3 (slow-wave sleep). Delta waves (0.5-4 Hz) dominate this deepest, most restorative sleep stage.

69. Which gland secretes melatonin to help regulate the sleep–wake cycle?

    Pineal gland. Releases melatonin in response to darkness signals from the SCN.

70. Which sleep disorder involves acting out dreams due to loss of REM atonia?

    REM sleep behavior disorder. Failure of normal REM paralysis allows physical dream enactment.

71. Identify the sleep disorder: acting out dreams due to loss of REM atonia.

    REM sleep behavior disorder. Failure of normal REM paralysis allows dream enactment.

72. Which sleep stage shows delta waves and is often called slow-wave sleep?

    NREM Stage 3 (N3). High-amplitude delta waves define deep sleep.

73. What is circadian rhythm?

    An endogenous $24-hour cycle regulating sleep and physiology. Internal biological clock that repeats approximately every 24 hours.

74. What is the typical order of stages in one normal sleep cycle starting after sleep onset?

    N1 $ N2 N3 N2 REM. Sleep progresses through deepening NREM stages before REM, cycling every 90 minutes with increasing REM duration.

75. Which sleep disorder involves airway obstruction causing repeated awakenings?

    Obstructive sleep apnea. Collapsed airway causes hypoxia, triggering brief arousals to breathe.

76. Which brain structure is the primary pacemaker for circadian rhythms?

    Suprachiasmatic nucleus (SCN) of the hypothalamus. SCN receives light input and synchronizes body rhythms.

77. What term describes a temporary circadian mismatch after rapid travel across time zones?

    Jet lag. Internal clock conflicts with new external time cues after travel.

78. What is the definition of consciousness in psychology?

    Awareness of internal states and external environment. Encompasses both subjective experiences and objective environmental perception.

79. Which sleep stage tends to increase in duration across successive sleep cycles?

    REM sleep. REM periods lengthen from ~10 to ~30 minutes through the night.

80. Which environmental cue is the primary zeitgeber for human circadian rhythms?

    Light (light–dark cycle). Photic input to SCN entrains internal clock to environmental day-night cycle.

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