9 - Principles Of Sensory Systems

Question 1

Sensation

Answer 1

Process of encoding events and stimuli by nervous system

Question 2

Perception

Answer 2

Process by which brain interprets sensory info

Question 3

Transduction

Answer 3

Conversion of one energy form to another

Question 4

In sensory receptors, a physical stimulus causes…

Answer 4

A change in mempot in receptor cell that performs transduction (receptor potential)

Question 5

Transmission and transduction

Answer 5

1. Mechanoreceptors in somatosensory system
2. Photoreceptors in visual system
3. Chemical receptors in taste and smell

Question 6

Mechanoreceptors in somatosensory system

Answer 6

Sensitive to different levels of pressure and vibration and contain mechanically gated ion channels

Question 7

What do eyelids, cornea, lens and pupil control?

Answer 7

Amount of light entering eye and image focus

Question 8

Opsin molecules in photoreceptor membrane absorb…

Answer 8

Photons of light, produce graded hyperpolarisation in mempot

Question 9

Rods are sensitive to _______ light levels

Answer 9

Low

Question 10

Cones sensitive to ______ light levels

Answer 10

High

Question 11

Are there photoreceptors at optic nerve head?

Answer 11

Nope - blindspot

Question 12

Salt sensations

Answer 12

Na+ channels

Question 13

Sour sensation

Answer 13

H+ channels

Question 14

Other taste sensations

Answer 14

Special G protein coupled receptors

Question 15

Are somatosensory mechanoreceptors spiking or non-spiking?

Answer 15

Spiking neurons

Question 16

Are APs different in each sensory system?

Answer 16

No - a nerve is a nerve and APs basically identical

Question 17

How do sensory neurons encode info?

Answer 17

In rate and timing of APs

Question 18

Rate coding

Answer 18

Different rates for different stimuli

Question 19

Temporal coding

Answer 19

Different timings for different stimuli

Question 20

T/F - a neuron can encode only one stimulus feature

Answer 20

False - a neuron can encode multiple stimulus features

Question 21

T/F - a neuron’s responses to repetitions of an identical stimulus are the same

Answer 21

False - highly variable

Question 22

To ensure reliable responses and account for variability,

Answer 22

Every stimulus encoded by population of neurons

Question 23

Forms of adaptation

Answer 23

• somatosensory: clothes on your back
• visual: mean luminance inside vs outside
• auditory: aircons

Question 24

Why have adaptations?

Answer 24

Limited no. Neurons available to encode stimuli
Optimise neurons to encode change
Matches neural sensitivity to prevailing environmental stats

Question 25

Topographic maps in cortex

Answer 25

Somatosensory, auditory and visual cortex each contain topographic map

Question 26

Somatosensory cortex somatotropin map

Answer 26

Adjacent neurons respond to touch of adjacent skin surface regions

Question 27

Auditory cortex contains a tonotopic map

Answer 27

Adjacent neurons optimally activated w/ same freq

Question 28

Visual cortex contains retinotopic map

Answer 28

Adjacent photoreceptors in retina encode adjacent parts of visual field
Adjacent neurons in primary visual cortex encode adjacent parts of visual field