Chap 12. Pt.II

Question 1

cold fibers

Answer 1

Thermoreceptors that fire at an ongoing moderate rate in response to sustained skin temperatures in the range of 17– 40° C.
Respond if skin temperature is abruptly cooled from a sustained neutral temperature

Question 2

Two major pathways in the spinal cord

Answer 2

Medial lemniscal pathway
large fibers that carry proprioceptive and touch information
Spinothalamic pathway
smaller fibers that carry temperature and pain information

Question 3

Neurons in area 3a

Answer 3

proprioceptive information carried by signals from muscle spindles and Golgi tendon organs located in tissues below the skin

Question 4

Neurons in areas 3b and 1

Answer 4

tactile information carried by signals from mechanoreceptors in the skin

Question 5

Neurons in area 2

Answer 5

proprioceptive information carried by signals from muscle spindles and Golgi tendon organs, and
tactile information carried by signals from mechanoreceptors in the skin

Question 6

homunculus

Answer 6

Body map on the cortex shows more cortical space allocated to parts of the body that are responsible for detail – cortical magnification

Question 7

Dorsal Path

Answer 7

• information used to guide actions that require tactile and proprioceptive input
• goes from S1 to the posterior parietal cortex and then to premotor cortex

Question 8

Ventral Path

Answer 8

• tactile and proprioceptive information used in perceiving and remembering object shape and identity
• Goes from S1 to S2 and then to prefrontal cortex and hippocampus

Question 9

PET imaging while cold stimulus applied to right hand

Answer 9

Activation in the left insular cortex which varied with the temperature applied to the hand
a site where nonpainful temperature sensations are represented in a somatotopic map used for, among other things, maintaining homeostasis ( e. g., constant body temperature)
R. insular: a site where the relative intensities of temperature sensations are evaluated.

Question 10

Cortical Representation of Pain: Pain Matrix

Answer 10

• Signals from nociceptors travel up the spinothalamic pathway and activate:
• Subcortical areas including the hypothalamus, limbic system, and the thalamus
• Cortical areas including S1 and S2 in the somatosensory cortex, the insula, and the anterior cingulate cortex
• These cortical areas taken together are called the pain matrix

Question 11

Analgesia

Answer 11

reducing sensitivity to pain by modulating the intensity of pain signals

Question 12

endogenous opioids

Answer 12

Compounds that belong to a class of substances called opiates; released by the body in response to painful or stressful experiences.

Question 13

endorphins

Answer 13

Endogenous opioids that have an inhibitory effect on pain- related neural signals in many areas of the central nervous system, reducing the perceived intensity of pain.

Question 14

Gate Control Model of Pain Perception

Answer 14

-The “gate” consists of substantia gelatinosa cells in the spinal cord (SG- and SG+)
-Input into the gate comes from:
Large diameter (L) fibers - information from tactile stimuli
Small diameter (S) fibers - information from nociceptors
Central control - information from cognitive factors from the cortex
-Pain does not occur when the gate is closed by stimulation into the SG- from central control or L-fibers into the T-cell
-Pain does occur from stimulation from the S-fibers into the SG+ into the T-cell

Question 15

Haptic Tests: 8

Answer 15

• lateral motion (Texture)
• pressure (hardness)
• skin contact (tempeture)
• unsupported holding (weight)
• enclosure (volume/global shape)
• contour following (volume/exact shape)
• functional test (specific function)
• part motion test (part motion)

Question 16

Controlling Pain

Answer 16

Pharmacological interventions
•Local or topical (e.g., lidocaine)
•Central (e.g., morphine & endogenous opiates)
Physical intervention
•Counterirritants (e.g., acupuncture)
Psychological Interventions
•Placebo effect
•Hypnosis
•Cognitive behavioural therapy
•Expectation
•Shifting attention

Question 17

Haptic perception

Answer 17

•is the active exploration of 3-D objects with the hand
•It uses three distinct systems:
–Sensory system
–Motor system
–Cognitive system
•Psychophysical research shows that people can identify objects haptically in 1 to 2 sec