6- General Principles of Sensory Systems

Question 1

What do vision receptors detect?

Answer 1

Light waves

Question 2

What do audition receptors detect?

Answer 2

Sound waves

Question 3

What is involved in vestibular senses?

Answer 3

Movement of liquid, gravity

Question 4

What are the 2 chemical senses?

Answer 4

Olfactory (smell) and gustatory (taste)

Question 5

What are the 2 body senses?

Answer 5

Touch and pain (somatosensory), movement (muscle, skin, joint)

Question 6

Somatosensory neurons (6)

Answer 6

• Free nerve endings
• Merkel’s disk
• Free nerve ending associated with root of a hair
• Pacinian corpuscle
• Meissner’s corpuscle
• Ruffini corpuscle

Question 7

What are somatosensory neurons sensitive to?

Answer 7

Physical distortion

Question 8

How does sensory perception differ?

Answer 8

Between species

Question 9

What does each sensory system have?

Answer 9

Specific receptors

Question 10

What do secondary receptive fields include?

Answer 10

Overlapping primary receptive fields

Question 11

What do primary sensory neurons converge upon?

Answer 11

1 secondary neuron

Question 12

What are receptors classified on? (3 things)

Answer 12

Morphology, adaptation, receptive fields

Question 13

Where is the most sensitive area in the body? (Two-point discrimination)

Answer 13

Fingertips

Question 14

3 reasons why fingertips are the most sensitive area of the body

Answer 14

• High density of mechanoreceptors
• Receptors with small receptive fields
• More brain tissue devoted to fingertips

Question 15

What are the 2 main processes in reception?

Answer 15

Transduction and transmission

Question 16

What is neural coding?

Answer 16

Stimulus properties need to be coded by neurons

Question 17

What are external signals transformed to in transduction?

Answer 17

Action potentials

Question 18

What is rate coding?

Answer 18

Coding by frequency/firing rate

Question 19

What is adaptation in rate coding?

Answer 19

Reduction of neural activity over time when stimulus is constantly presented

Question 20

What is the system more interested in with rate coding?

Answer 20

More interested in changes than consistency

Question 21

What is place coding?

Answer 21

Coding by location

Question 22

What is labelled-line coding?

Answer 22

Coding to a specific sense

Question 23

What is the problem with labelled-line coding?

Answer 23

Receptors aren’t specific enough to detect fine differences

Question 24

What is population coding?

Answer 24

Coding by multiple receptors

Question 25

What determines specific sensation?

Answer 25

Activation of many neurons together

Question 26

What is firing rate limited by?

Answer 26

Refractory period

Question 27

What is the pathway in transmission?

Answer 27

From neuron to cortex: receptor --> peripheral pathway --> thalamus --> primary sensory cortex --> secondary cortical areas

Question 28

What is tonotopy?

Answer 28

A columnar organisation of cells with similar binaural interaction

Question 29

What is somatopy?

Answer 29

Differences in acuity correspond to the differences in relative proportions of the secondary sensory cortex devoted to analysing information from these body regions

Question 30

What does the bottom-up approach suggest?

Answer 30

Extraction of stimulus features from data without prior knowledge/memory/attention

Question 31

What does the top-down approach suggest?

Answer 31

Influence from higher levels of nervous system to lower