MCAT Monday: Processing the Environment - Sleep and Consciousness


Foundational Concept 6: Biological, psychological, and socio-cultural factors influence the ways that individuals perceive, think about, and react to the world. All sensory processing begins with first detecting a stimulus in the environment through sensory cells, receptors, and biological pathways.


After collecting sensory information, we then interpret and make sense of it. Although sensation and perception are distinct functions, they are both influenced by psychological, social, and biological factors and therefore become almost indistinguishable in practice. This complexity is illuminated by examining human sight, hearing, touch, taste, and smell. (via AAMC)


Practice Videos:

Practice Questions:

1. The release of which neurotransmitter is associated with an increase in alertness? Choose 1 answer:

  • A: Beta-endorphin

  • B: Serotonin

  • C: GABA

  • D: Norepinephrine

2. The Stroop test is considered to be one of the most effective tests of automatic and automated performance. A team of cognitive psychologists designed an experiment to test whether hypnotic suggestion could reduce Stroop interference. A group of volunteers were screened for hypnotic susceptibility. All participants scored above the highly susceptible range and were grouped into either the experimental group (hypnotic suggestion) or control (no hypnosis before suggestion). Participants in the experimental group were hypnotized. Both groups were given the suggestion that the participant was playing a game, meaningless symbols would appear in an invented language printed in different colored ink. The goal of the game was to quickly and accurately make the choice that corresponds to the ink color. The results are shown below (α = 0.01). What conclusion can be made based on these data?

Choose 1 answer:

  • A: The effect of hypnosis was not significant, except when comparing between hypnosis performed and not-performed.

  • B: Both groups were accurate in responding; however, following hypnosis the interference caused by the Stroop effect was significantly reduced.

  • C: Being hypnotized had a minimal effect on the reaction time and accuracy of the experimental group. The control group lacked Stroop interference.

  • D: There was a significant difference in reaction time between the experimental and control groups, but not in accuracy.

3. A clinical trial is designed to test the efficacy of mindfulness-based stress reduction (MBSR). The participants (diagnosed with agoraphobia based on the DSM-5 criteria) were divided into groups after being matched for age, socioeconomic status, and level of anxiety. Groups received interventions as follows:

  • Group 1: received MBSR training for 6 weeks Group 2: was given a drug intervention (group members were instructed to take “a newly approved and released anxiety drug”, actually a sugar pill) for acute anxiety. Group 3: received cognitive behavioral therapy for 6 weeks. Group 4: received a therapy created for the experiment by the researchers.

Which group was the Active comparator arm? Choose 1 answer:

  • A: Group 1

  • B: Group 2

  • C: Group 3

  • D: Group 4

4. Which of these drugs works as an agonist at acetylcholine receptor sites resulting in stimulation of the CNS? Choose 1 answer:

  • A: Amphetamines

  • B: Nicotine

  • C: Alcohol

  • D: LSD

5. Which of these dopamine pathways is associated with reward, motivation, and many of the positive symptoms of schizophrenia? Choose 1 answer:

  • A: Tuberoinfundibular pathway

  • B: Mesocortical pathway

  • C: Mesolimbic pathway

  • D: Nigrostriatal pathway

6. A sleep scientist wants to investigate the cognitive effects of sleep deprivation. After surveying 100 respondents, participants (n=40) with histories of regular sleep, no caffeine, nicotine, or drug usage, and no history of sleep disorder conditions were selected for the study. They complete tasks measuring alertness, mood, and cognitive performance every 24 hours for 72 hours. What is a possible confound in this study? Choose 1 answer:

  • A: People exhibit differences in chronotype over long periods of sleep deprivation.

  • B: People may experience micro sleeps over long periods of sleep deprivation.

  • C: People are often not aware of their sleep disorders.

  • D: People can have trouble sleeping during long periods of sleep deprivation.

7. What stage of sleep is depicted by this EEG?

Choose 1 answer:

  • A: Stage 1 NREM

  • B: Stage 2 NREM

  • C: Stage 3 and stage 4 NREM

  • D: REM


8. Which of these criteria is necessary for a biological rhythm to be described as a circadian rhythm? Choose 1 answer:

  • A: The rhythm must have a period of no more than 24 hours.

  • B: The rhythm must be expressed according to social factors that determine the period of the cycle.

  • C: The rhythm must be internally generated.

  • D: The rhythm must reflect a light dark cycle.

9. Which of these people is NOT accruing a sleep debt? Choose 1 answer:

  • A: A 6-month-old baby who gets 11 hours of sleep a night.

  • B: A 4-year-old girl who gets 9 hours of sleep a night.

  • C: A 9-year-old boy who gets 8 hours of sleep a night.

  • D: A 40-year-old woman who gets 7 hours of sleep a night.

10. Narcolepsy is an alertness disorder associated with excessive sleepiness, sleep attacks, and cataplexy. The study of narcolepsy in humans has been informed by the study of Dachshunds, Doberman Pinchers, and Labrador Retrievers. In these dogs, possession of two recessive genes that control a neurotransmitter receptor, which affects the control of sleep and arousal, and results in direct transitions from an alert state to REM sleep. What neurotransmitter is being described? Choose 1 answer:

  • A: Hypocretin / orexin

  • B: GABA

  • C: Serotonin

  • D: Dopamine

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