Chapter 4: Sensation and Perception 4.5 (Somatosensory)

Question 1

Body senses

Answer 1

somatosenses

Question 2

Haptic perception

Answer 2

active exploration of the environment by touching and grasping objects with our hands

Question 3

Tactile receptive field

Answer 3

small patch of skin that relays information about pain, pressure, texture, pattern, or vibration to touch receptors underneath

Question 4

Thermoreceptors

Answer 4

nerve fibers that sense cold and warmth, respond when skin temperature changes

Question 5

3 important principles regarding the neural representation of the body’s surface

Answer 5

(1) Left half of the body is represented in the right half of the brain and vice versa (contralateral) (2) Different locations on the body send sensory signals to different locations in the somatosensory cortex in the parietal lobe (3) Distinction between “what” and “where” pathways in touch (like dorsal and ventral streams)

Question 6

Congenital insensitivity to pain

Answer 6

rare inherited disorder that impairs pain perception, often causes mutilation on self and increased risk of dying

Question 7

A-delta fibres

Answer 7

thin, myelinated fact-acting axons that transmit initial sharp pain

Question 8

C-fibres

Answer 8

thick, slower axons that aren’t myelinated that transmit the longer-lasting, duller persistent pain

Question 9

2 pathways pain travels along

Answer 9

Sensory/discriminative pathway from the spinal cord to the somatosensory cortex and emotional/motivational pathway from the spinal cord to the emotional/motivational centers of the brain (amygdala in the limbic system)

Question 10

Sensory/discriminative pain pathway

Answer 10

Sends signals to the somatosensory cortex, identifying where the pain is occurring and what type of pain it is (sharp, burning, or dull)

Question 11

Emotional/motivational pathway

Answer 11

Sends signals to the emotional and motivational centers of the brain such as the hypothalamus, amygdala, and frontal lobe; aspect of pain that motivates us to escape or relieve it

Question 12

Referred pain

Answer 12

sensory information from internal and external areas converges on the same nerve cells in the spinal cord

Question 13

Is there a correlation between pain type and pain intensity?

Answer 13

They have a less-than-perfect correlation. Pain intensity cannot always be predicted solely from the extent of the injury that causes the pain.

Question 14

Gate-control theory

Answer 14

signals arriving from pain receptors in the body can be stopped or gated by inhibitory interneurons in the spinal cord via feedback (e.g. skin receptors/rubbing area of injury) or from the brain, which modulates the activity of pain-transmission (projection) neurons

Question 15

Periaqueductal grey (PAG)

Answer 15

Region in the midbrain where the brain’s feedback to the spinal cord comes from; responds to naturally occurring endorphins that activate the PAG which send inhibitory signals to neurons in the spinal cord that suppress pain signals to the brain, also responds to opiate drugs like morphine

Question 16

Pain facilitation signal

Answer 16

Kind of feedback signal from the brain that can increase the sensation of pain, activated by events such as infection and learned danger signals, and presumably evolved to motivate sick people to devote their energy to healing

Question 17

Bottom-up control of perception

Answer 17

Control of perception by senses

Question 18

Top-bottom control of perception

Answer 18

Influence of brain on the experience of touch and pain e.g. visual illusions and the Gestalt principles of closure (filling in what isn’t really there)

Question 19

Proprioception

Answer 19

your sense of body position, relies on vestibular system

Question 20

Vestibular system

Answer 20

three fluid-filled semicircular canals and adjacent organs located next to the cochlea in each inner ear, wherein detected motion of fluid when our heads move enables us to maintain our balance (along with visual cues)

Question 21

How do we experience touch?

Answer 21

Skin registers stimuli of temperature and pressure, designated receptors in your skin transmit the signal along the cranial nerves or spinal nerves, through the thalamus, to the area of the somatosensory cortex that processes the body parts that were touched

Question 22

How do we experience pain?

Answer 22

When you touch something painful (e.g. heat), pain stimuli is registered with fast fibers (myelinated) for sharp pain and slow fibers for duller pain (not myelinated) through the spinal cord to the brain