• Julianna Kearney

MCAT Monday: Processing the Environment - Somatosensation



Foundational Concept 6B: The way we think about the world depends on our awareness, thoughts, knowledge, and memories. It is also influenced by our ability to solve problems, make decisions, form judgments, and communicate. Psychological, sociocultural, and biological influences determine the development and use of these different yet convergent processes.

Biological factors underlie the mental processes that create our reality, shape our perception of the world, and influence the way we perceive and react to every aspect of our lives. (via AAMC)


Practice Videos:

Practice Questions:

1. When a cup starts to slip from one’s hand it makes quick vibrations, which are felt through the hand. Which receptor, that is important in perceiving vibration, is being triggered? Choose 1 answer:

  • A: The Merkel receptor, a slow-adapting (SAI) mechanoreceptor that fires to continuous pressure.

  • B: The Ruffini cylinder, a slow-adapting (SA II) mechanoreceptor that fires to continuous pressure.

  • C: The Meissner corpuscle, a fast-adapting (FA I) mechanoreceptor that fires to ‘on’ and ‘off’ stimulus.

  • D: The Pacinian corpuscle, a fast adapting (FA II) mechanoreceptor that fires to ‘on’ and ‘off’ stimulus.

2. A researcher is attempting to test the hypothesis that vibrotaction is important in the perception of fine or closely spaced texture. She uses a 10 Hz vibration stimulus applied to the skin for 7 minutes to adapt the Meissner corpuscle and a 250 Hz stimulus applied for 7 minutes to adapt the Pacinian corpuscle. What effect did adaptation of the Meissner corpuscle and the Pacinian corpuscle have on the ability to perceive texture, based on the chart below? Choose 1 answer:

  • A: The adaptation of the Pacinian corpuscle caused the patient to be unable to reliably sense fine texture.

  • B: The adaptation of the Meissner corpuscle caused the patient to be unable to reliably sense fine texture.

  • C: The adaptation did not affect fine texture perception.

  • D: The adaptation of both the Meissner and Pacinian corpuscle likely significantly affected fine texture perception.

3. What term describes how a neuron down-regulates its responsiveness over time to a constant stimulus? Choose 1 answer:

  • A: Dishabituation

  • B: Haptic perception

  • C: Adaptation

  • D: Active touch

4. Which of these factors does NOT affect the perception of pain? Choose 1 answer:

  • A: The expected pain intensity.

  • B: The attention given to the pain.

  • C: he actual intensity of the painful stimulus.

  • D: The existence of the neurons producing the pain stimulus.

5. Tactile acuity can be measured by comparing the two-point thresholds of different parts of the body. Which of these areas would have the highest tactile acuity? Choose 1 answer:

  • A: Sole of the foot

  • B: Upper Lip

  • C: Thumb

  • D: Forearm

6. A neuroscientist conducted an investigation on his patient prior to brain surgery to remove a lesion in the primary somatosensory cortex (S1). When stimulating the ventral part of S1, she caused sensations on the face of the patient. As she moved up, the patient felt sensations in the hand, head, and leg. When she reached the dorsal S1, the patient felt sensations in the foot. What cortical map of the body is the neuroscientist tracing to determine whether the lesion affected areas of S1? Choose 1 answer:

  • A; Tonotopy

  • B: Homunculus

  • C: Connectome

  • D: Dermatome

7. Which sense relates to the perception of motion and uses neurons in muscles, joints, and tendons? Choose 1 answer:

  • A: Proprioception

  • B: Kinesthesis

  • C: Nociception

  • D: Vestibular sense

8. Ménière's disease is an inner ear disorder, which affects balance and hearing. Symptoms include extreme vertigo, loss of hearing, tinnitus, and a feeling of fullness or pressure that builds up in the ear. One symptom, called the “otolithic crisis of Tumarkin”, results from a mechanical deformation of the utricle and saccule. The patient’s hair cells of the otoliths are activated and he or she will suddenly feel tilted (although standing up straight). In extreme cases, the patient will fall to the ground, while still conscious, and feel as though someone violently pushed him or her down. Which statement is a likely cause of this symptom? Choose 1 answer:

  • A: The deformation of the otolith organs causes a reflex in the somatosensory system.

  • B: The deformation of the otolith organs causes a reflex in proprioceptive system.

  • C: The deformation of the otolith organs causes a reflex in the vestibular system.

  • D: The deformation of the otolith organs causes a reflex in the kinesthesic system.

9. Participants were given hypnotic suggestions to either increase or decrease the subjective intensity of immersing a hand in extremely cold water. Afterwards, the participants were asked to rate the intensity and unpleasantness of the pain experienced. The results are shown above. Which statement accurately describes a possible conclusion based on this data? Choose 1 answer:

  • A; Hypnotic suggestion had a significant effect on only the sensory component of pain.

  • B: Hypnotic suggestion likely had a significant effect on both the sensory and affective components of pain.

  • C: Hypnotic suggestion did not have an effect on either the sensory or affective components of pain.

  • D: Hypnotic suggestion had a significant effect on only the affective component of pain.

10. The multimodal nature of pain echoes the belief that pain is both a sensory and an affective experience. Which of these sensations is a term of the affective component of pain? Choose 1 answer:

  • A: Sharp

  • B: Burning

  • C: Throbbing

  • D: Torturing

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