Topic 8.2

Question 1

4 basic properties of sensory stimulus

Answer 1

Modality
Intensity
Duration
Location

Question 2

10 major modalities

Answer 2

• Vision
• hearing
• Smell
• Taste
• Touch
• Flutter-vibration
• Temperature
• Proprioception
• Linear and rotational acceleration
• Nociception

Question 3

What is threshold

Answer 3

The smallest level of a stimulus that can be detected 50% of the time

Question 4

3 ways of encoding stimulus

Answer 4

• AP frequency
• Population of receptors activated
• Types of receptors activated

Question 5

Steven’s power law

Answer 5

Sensation magnitude = k x I^n
K : proportionality constance (dpdt on unit of intensity)
n : power exponent (depends on modality)

Question 6

Weber Fechner law

Answer 6

k = dI/I

K = constant, depends on modality
dI = minimal change in the intensity required to produce just noticeable change
I = intensity of stimulus where change occurs

Question 7

What is 2 point discrimination

Answer 7

The ability to recognize that 2 nearby objects touching the skin are 2 distinct points

Question 8

Information coding by the receptor (5)

Answer 8

• Anatomy of the receptor (cell type)
• Location of the cell body of order neuron
• Vertical and horizontal organization of fibers
• Topology : dermatome / tonotopy
• Receptive field

Question 9

What is a dermatome

Answer 9

An area of ski that is supplied by afferent nerve fibers from a single dorsal root of spinal nerve

Question 10

Bipolar neurons location (4)

Answer 10

• olfactory
• retinal
• auditory
• vestibular

Question 11

What is a receptive field

Answer 11

Are that can trigger neuronal responses when stimulated, that the neuron can receive information from

Question 12

A alpha diameter and velocity of conduction

Answer 12

12-20micro meter

72-120 ms

Question 13

A beta fibre diameter and conduction velocity

Answer 13

6-12 micrometer

36-72 ms

Question 14

A delta diameter and conduction speed

Answer 14

1-6 micro meter

4-36 ms

Question 15

C fiber diameter and velocity

Answer 15

0. 2-1.5 micrometer

0. 4-2 ms

Question 16

Receptors in hairy skin (2)

Answer 16

• Hair follicle (free nerve ending)

- Ruffini’s corpuscle

Question 17

Receptors in non hairy skin (3)

Answer 17

• Merkel’s disc
• Meissner corpuscle
• Pacinian corpuscle

Question 18

Hair follicule adaptation and role

Answer 18

• Rapid adaptation

- Velocity, direction of movement

Question 19

Ruffini corpuscle adaptation and role

Answer 19

• slow adaptation

- stretch, joint rotation

Question 20

Meissner corpuscle adaptation and role

Answer 20

• rapid adaptation

- touch, point discrimination, fluttering

Question 21

Merkel disc adaptation and role

Answer 21

• slow adaptation

- pressure, edges, points

Question 22

Pacinian corpuscle adaptation and role

Answer 22

• rapid adaptation

- sense vibration, tapping

Question 23

Projection somatosensory pathways

Answer 23

Brodmann area 3, 1, 2 (primary somatosensory cortex)

Question 24

Type of interneurons in VPL and VPM

Answer 24

GABAergic inhibitory interneurons

Question 25

Where is info from the 4 areas of S1 sent?

Answer 25

To are 5 and S2

Question 26

3 ways for lateral inhibition

Answer 26

1 - feedback inhibition
2 - feed forward inhibition
3 - descending inhibition