Neurobiology of Sensory Perception and Pain Quiz

1. Describe and identify the DRG cell ending types and the sensory modalities transduced by each type.

Dorsal root ganglia cells have cell bodies at both ends of the ganglia.

Dorsal root ganglia cells are located in the middle of the ganglia.

DRG cell endings include encapsulated receptors (touch/vibration/pressure/stretch), proprioceptors (muscle length & tension), and free nerve endings (pain & temperature).

The sensory modalities transduced by DRG cells are limited to taste and smell.

The correct answer highlights that the cell body is located only at the very end of the dorsal root ganglia. The incorrect answers provide false information or incorrect associations related to the structure and function of DRG cells.

Explanation

The correct answer highlights that the cell body is located only at the very end of the dorsal root ganglia. The incorrect answers provide false information or incorrect associations related to the structure and function of DRG cells.

2. What are ion channels that transduce sensory modalities? How do we know that mechanosensing channels are cation that open upon membrane displacement?

By analyzing the chemical composition of the cell membrane

By observing changes in cell shape under a microscope

By measuring the temperature changes around the cell during membrane displacement

Mechanosensing channels can be identified through specific experimental procedures involving the recording of ion flow with a voltage clamp, which allows for categorization based on response types.

Explanation

Mechanosensing channels can be identified through specific experimental procedures involving the recording of ion flow with a voltage clamp, which allows for categorization based on response types.

3. Describe and understand the difference between SA and RA currents and relate them to different physiological properties of DRGs.

SA DRG peaks quickly and adapts rapidly to the pressure stimulus.

RA DRG current remains constant as long as pressure stimulus is applied.

IA DRG only responds well to the 'first touch' pressure stimulus.

SA currents persist during sustained stimuli (pressure/stretch), while RA currents fire only at onset/offset (vibration/light touch).

In this question, the correct answer explains the behavior of RA, SA, and IA DRGs and how they respond to pressure stimuli. Incorrect answers provided do not accurately depict the differences between SA and RA currents in relation to their physiological properties.

Explanation

In this question, the correct answer explains the behavior of RA, SA, and IA DRGs and how they respond to pressure stimuli. Incorrect answers provided do not accurately depict the differences between SA and RA currents in relation to their physiological properties.

4. Describe the physiology of TRP channels and how they transduce temperature and pain info what other channels are involved in pain transduction?

TRP channels are not involved in temperature or pain transduction

TRP channels are primarily found in the brain and not in peripheral nerves

TRP channels are only activated by physical pressure

The correct answer explains the involvement of TRP channels in temperature and pain transduction, along with the role of nociceptors. The incorrect answers provided do not accurately describe the physiology of TRP channels or their function in transducing temperature and pain information.

Explanation

The correct answer explains the involvement of TRP channels in temperature and pain transduction, along with the role of nociceptors. The incorrect answers provided do not accurately describe the physiology of TRP channels or their function in transducing temperature and pain information.

5. Describe a specific parallel map and an orthogonal map in the primary somatosensory cortex.

AUDITORY

SMELL

READ

TACTILE

In the primary somatosensory cortex, a specific parallel map refers to the topographical arrangement of body parts, known as the somatotopic map. An orthogonal map refers to the organization of different sensory inputs within the cortex, such as visual, auditory, and somatosensory inputs being arranged in orthogonal columns.

Explanation

In the primary somatosensory cortex, a specific parallel map refers to the topographical arrangement of body parts, known as the somatotopic map. An orthogonal map refers to the organization of different sensory inputs within the cortex, such as visual, auditory, and somatosensory inputs being arranged in orthogonal columns.

6. Describe how phantom limb sensations and pain relate to cortical maps, and how mirror box therapy indicates a 'top down' effect on sensory cortical maps.

Cortical maps have no influence on the perception of phantom limb pain.

Phantom limb sensations are a result of actual physical limbs reappearing after amputation.

Mirror box therapy directly affects the physical reconstruction of missing limbs.

Phantom limb sensations and pain are intricately linked to cortical maps due to the reorganization of brain areas, which is why mirror box therapy, which works on the brain's perception, shows a 'top down' effect on sensory cortical maps.

Explanation

Phantom limb sensations and pain are intricately linked to cortical maps due to the reorganization of brain areas, which is why mirror box therapy, which works on the brain's perception, shows a 'top down' effect on sensory cortical maps.

7. Describe and name the descending pathways that modify pain sensation through endogenous opiates.

Pain is modulated only at the spinal cord by GABAergic neurons without involvement of higher centers.

Pain modulation occurs through direct activation of TRP and Piezo channels by cortical inputs.

Endogenous opiates act only at peripheral nerve endings without central involvement.

The descending pathways that modify pain sensation through endogenous opiates involve the dorsal horn neurons in the gray matter and the periaqueductal gray matter, not the spinothalamic tract, ventral horn neurons, or cerebellar pathways.

Explanation

The descending pathways that modify pain sensation through endogenous opiates involve the dorsal horn neurons in the gray matter and the periaqueductal gray matter, not the spinothalamic tract, ventral horn neurons, or cerebellar pathways.

8. Describe the pathways and major receptors responsible for itch sensation.

Itch uses the same pathways as vibration sense and is mediated by Pacinian corpuscles

Itch is transmitted exclusively by Aβ mechanoreceptors and blocked only by opioid receptors.

Itch signals bypass the spinal cord and travel directly from skin to thalamus.

The correct answer provides detailed information about the pathways and major receptors responsible for itch sensation, while the incorrect answers misrepresent or provide inaccurate information about the topic.

Explanation

The correct answer provides detailed information about the pathways and major receptors responsible for itch sensation, while the incorrect answers misrepresent or provide inaccurate information about the topic.

9. Which TRP channels open to menthol and which open to capsaican?

TRPM8 opens to menthol (cool), and TRPV1 opens to capsaicin (heat/pain).

TRPM8 to menthol, TRPV4 to capsaican

TRPV4 to menthol, TRPA1 to capsaican

TRPV1 to menthol, TRPA1 to capsaican

Menthol activates TRPA1 and TRPM8 channels, while capsaican activates TRPV4 (and TRPV1 indirectly). TRPV1 is typically associated with extreme heat rather than menthol activation.

Explanation

Menthol activates TRPA1 and TRPM8 channels, while capsaican activates TRPV4 (and TRPV1 indirectly). TRPV1 is typically associated with extreme heat rather than menthol activation.

10. What channels transduce pain?

Voltage-gated sodium channels

Potassium channels

Calcium channels

Pain sensation is transduced through various ion channels in the body. The correct answer options provided are known to play a key role in pain transduction, making them relevant choices for the question.

Explanation

Pain sensation is transduced through various ion channels in the body. The correct answer options provided are known to play a key role in pain transduction, making them relevant choices for the question.

11. Name the different tongue papillae and describe the location of taste buds, explain how they differ in content of different taste receptor cells.

Only filiform papillae contain all taste buds.

All papillae contain equal taste buds.

Taste buds only detect salty taste.

Taste buds are located within the papillae of the tongue, with different types of papillae containing varying concentrations of taste receptors for different tastes, such as sweet, salty, sour, bitter, and umami.

Explanation

Taste buds are located within the papillae of the tongue, with different types of papillae containing varying concentrations of taste receptors for different tastes, such as sweet, salty, sour, bitter, and umami.

12. Describe the responses of the population of chordi-tempani axons to different tastants and explain the implication of this response pattern for both the receptor types on taste cells, and for how taste info is processed (population code or labeled line).

All chorda tympani axons respond equally to all tastants, indicating a labeled line theory of taste processing.

Only one chorda tympani axon is responsible for detecting all tastants, suggesting a specific labeled line for each taste.

The correct answer provided highlights that there are specific responses of chorda tympani axons to different tastants, indicating a population code for taste information processing. The incorrect answers showcase alternative scenarios that do not align with the observed response patterns and theoretical implications.

Explanation

The correct answer provided highlights that there are specific responses of chorda tympani axons to different tastants, indicating a population code for taste information processing. The incorrect answers showcase alternative scenarios that do not align with the observed response patterns and theoretical implications.

13. Identify the specific transduction channels and receptors in taste receptor cells for salty, sour, bitter, sweet and umami. Note the unique and shared mechanisms of transduction.

SALT: TRPM5; SOUR: T2R5; SWEET: ENaC; UMAMI: PKD2L

SALT: T1R1; SOUR: ENaC; SWEET: T2R5; UMAMI: PLCB2

SALT: PLCB2; SOUR: TRPM5; SWEET: PKD2L; UMAMI: T1R2

The correct answer includes the specific transduction channels and receptors for each taste sensation, highlighting their unique and shared mechanisms of transduction. The incorrect answers provided do not accurately represent the components involved in taste transduction for each taste sensation.

Explanation

The correct answer includes the specific transduction channels and receptors for each taste sensation, highlighting their unique and shared mechanisms of transduction. The incorrect answers provided do not accurately represent the components involved in taste transduction for each taste sensation.

14. Describe the nature of odorant receptor diversity and the pattern of expression of different receptors on different olfactory neurons.

Odorant receptor diversity is not important in the sense of smell.

Olfactory neurons express all types of receptors simultaneously.

Each odorant receptor can be expressed on multiple olfactory neurons.

The correct answer highlights the significance of odorant receptor diversity in olfaction and explains the specific pattern of receptor expression on olfactory neurons. The incorrect answers are refuted based on the established understanding of odorant receptor diversity and expression patterns in olfactory neurons.

Explanation

The correct answer highlights the significance of odorant receptor diversity in olfaction and explains the specific pattern of receptor expression on olfactory neurons. The incorrect answers are refuted based on the established understanding of odorant receptor diversity and expression patterns in olfactory neurons.

15. What is anosmia?

Loss of vision.

Lose sense of taste.

Hearing impairment.

Lose sense of taste.

Anosmia refers to the loss of the sense of smell, not taste, vision, or hearing.

Explanation

Anosmia refers to the loss of the sense of smell, not taste, vision, or hearing.

16. Identify the locations of the first 4 synapses in the olfactory system.

3. Amygdala to parietal cortex

2. Hippocampus to frontal lobe

1. Cerebellum to occipital lobe

The olfactory system involves specific pathways and locations for the transmission of signals related to smell. The incorrect answers provided do not correspond to the actual synapse locations within the olfactory system as outlined in the correct answer.

Explanation

The olfactory system involves specific pathways and locations for the transmission of signals related to smell. The incorrect answers provided do not correspond to the actual synapse locations within the olfactory system as outlined in the correct answer.

17. Describe the mapping of olfactory stimuli responses across the glomeruli of the olfactory bulb.

Each glomeruli can receive multiple axons from the same olfactory receptor neuron, causing redundancy in stimulus processing.

Glomeruli receive axons from only one olfactory receptor neuron, which results in lack of diversity in odor perception.

Each glomeruli receive axons from multiple olfactory receptor neurons, leading to overlap in responses.

The correct answer explains that each glomeruli receives axons from different olfactory receptor neurons, allowing for a wide range of odor detection. The incorrect answers suggest scenarios that are not accurate in describing the mapping of olfactory stimuli across glomeruli.

Explanation

The correct answer explains that each glomeruli receives axons from different olfactory receptor neurons, allowing for a wide range of odor detection. The incorrect answers suggest scenarios that are not accurate in describing the mapping of olfactory stimuli across glomeruli.

18. How does the relative olfactory sensitivity vary in different mammals, and what anatomical correlation is associated with this sensitivity?

Mammals with lower olfactory sensitivity typically have more olfactory receptors.

Olfactory sensitivity in mammals is not related to the number of olfactory receptors.

Mammals that have more olfactory sensitivity have a lot more receptors.

Mammals with higher olfactory sensitivity have smaller olfactory bulbs.

Olfactory sensitivity in mammals is directly correlated with the number of olfactory receptors, with more receptors leading to higher sensitivity.

Explanation

Olfactory sensitivity in mammals is directly correlated with the number of olfactory receptors, with more receptors leading to higher sensitivity.

19. Name the layers of the cornea. Which layer is reshaped during LASIK surgery to change corneal focusing?

Epithelium

Descemet's membrane

Epithelium, bowman's membrane, stroma, descemet's membrane, endothelium*stroma can be reshaped by lasek surgery if thick enough

Endothelium

During LASIK surgery, the stroma layer of the cornea is reshaped to correct vision.

Explanation

During LASIK surgery, the stroma layer of the cornea is reshaped to correct vision.

20. Name the 6 neuronal cell types of the retina.

1. glial cell 2. pyramidal cell 3. Purkinje cell

1. rod 2. cone 3. horizontal cell 4. bipolar cell 5. amacrine cell 6. ganglion cell

The incorrect answers provided do not represent neuronal cell types found in the retina. Glial cells are support cells, pyramidal cells are found in the cerebral cortex, and Purkinje cells are found in the cerebellum.

Explanation

The incorrect answers provided do not represent neuronal cell types found in the retina. Glial cells are support cells, pyramidal cells are found in the cerebral cortex, and Purkinje cells are found in the cerebellum.

21. Distinguish between macular degeneration and retinitis pigmentosa.

Retinitis pigmentosa primarily affects rod photoreceptors in the periphery and occurs in children, while macular degeneration specifically targets cone photoreceptors in the fovea and is more common in older individuals.

Explanation

Retinitis pigmentosa primarily affects rod photoreceptors in the periphery and occurs in children, while macular degeneration specifically targets cone photoreceptors in the fovea and is more common in older individuals.

22. Describe the signaling cascade and electrophysiological responses in rod and cone photoreceptors. What accounts for the adaptive response in cones?

3. The adaptive response in cones is primarily due to the absence of opsins and rhodopsin in their photoreceptors.

2. Transducin decreases cGMP levels, which opens ion channels and increases sodium and calcium influx.

The correct answer details the activation of opsins and rhodopsin in response to light exposure, leading to changes in cGMP levels and ion channel activity. The incorrect answers misinterpret the mechanisms involved in the signaling cascade and adaptive responses in cones.

Explanation

The correct answer details the activation of opsins and rhodopsin in response to light exposure, leading to changes in cGMP levels and ion channel activity. The incorrect answers misinterpret the mechanisms involved in the signaling cascade and adaptive responses in cones.

23. What is the basis for the different responses in ON and OFF bipolar cells?

ON bipolar cells hyperpolarize when glutamate release is decreased, while OFF bipolar cells depolarize.

They both depolarize in response to increased glutamate release.

ON and OFF bipolar cells exhibit the same response to changes in glutamate release.

24. What is the detailed retinal circuitry that results in the center surround responses in ganglion cells?

Ganglion cells have individual preferences for either on or off center responses regardless of bipolar cell input.

The center surround responses in ganglion cells are solely determined by the number of synapses involved in the retinal circuitry.

Photoreceptor cells respond directly to stimulus in the center of their receptive field.

25. What are the two most common types of dichromatic color blindness?

Monochromacy (single-color perception), Cone monochromacy (only one functioning cone type)

Tritanopia (loss of S opsin), Anomalous trichromacy (defective L or M opsin)

Protanopia (loss of L opsin), Deuteranopia (lose of M opsin)

Dichromacy (complete color blindness), Achromatopsia (total color blindness)

Dichromatic color blindness refers to the loss of one type of cone photoreceptor, leading to difficulty in distinguishing colors. The correct answer includes Protanopia and Deuteranopia, which involve the loss of L or M opsins, respectively. The incorrect answers provide other types of color vision deficiencies that do not match the most common dichromatic conditions.

Explanation

Dichromatic color blindness refers to the loss of one type of cone photoreceptor, leading to difficulty in distinguishing colors. The correct answer includes Protanopia and Deuteranopia, which involve the loss of L or M opsins, respectively. The incorrect answers provide other types of color vision deficiencies that do not match the most common dichromatic conditions.

26. What are the circuitry implications (genetically predetermined or learned) of the demonstration of successful gene therapy for dichromatic color blindness in primates?

Mixed

Learned

Read

Not significant

The circuitry implications of gene therapy for dichromatic color blindness in primates are primarily genetically predetermined as the therapy targets specific genetic defects responsible for the color blindness. Although some components of learning may come into play during the process, the main focus is on correcting the genetic mutation.

Explanation

The circuitry implications of gene therapy for dichromatic color blindness in primates are primarily genetically predetermined as the therapy targets specific genetic defects responsible for the color blindness. Although some components of learning may come into play during the process, the main focus is on correcting the genetic mutation.

27. Describe the ipsilateral and contralateral projections from each eye, and explain how lesions in different parts of the visual pathway would impair vision. Also, identify the parts of the visual field transmitted by inferior and superior projections to the visual cortex.

Lesions before the optic chiasm always result in vision loss in both eyes.

All layers in the LGN receive input from both eyes equally.

There are only two layers in the LGN, one for each eye.

The correct answer specifies the segregation of input in the LGN, the effect of lesions on vision based on location, and the number of layers dedicated to each eye. The incorrect answers provide misleading information that contradicts established knowledge in the field of vision and visual processing.

Explanation

The correct answer specifies the segregation of input in the LGN, the effect of lesions on vision based on location, and the number of layers dedicated to each eye. The incorrect answers provide misleading information that contradicts established knowledge in the field of vision and visual processing.