Chapter 2: Basic Principles of Sensory Physiology

Question 1

neurons

Answer 1

store electrical signals

Question 2

cell body

Answer 2

contains mechanisms to keep the cell alive

Question 3

dendrites

Answer 3

branch out from the cell body to receive electrical signals from other neurons

Question 4

axon

Answer 4

filled with fluid that conducts electrical signals

Question 5

sensory receptors

Answer 5

neurons specialized to respond to environmental stimuli

Question 6

how are electrical signals measured

Answer 6

using small electrodes

Question 7

recording electrode

Answer 7

an electrode with its recording tip inside the neuron

Question 8

reference electrode

Answer 8

an electrode located some distance away from the neuron so it is not affected by the electrical signals

Question 9

what is the resting potential of a neuron?

Answer 9

the negative charge of the neuron relative to its surroundings (-70 mV)

Question 10

action potential

Answer 10

a predictable rise and fall of the charge inside the axon relative to the outside

Question 11

what is the neuron’s membrane potential at the peak of an action potential?

Answer 11

40 mV

Question 12

propagated response

Answer 12

once the response is triggered, it travels down the axon without decreasing in size

Question 13

refractory period

Answer 13

the interval between the time one nerve impulse occurs and the next one can be generated in the axon

Question 14

spontaneous activity

Answer 14

action potentials that occur in the absence of environmental stimuli

Question 15

size of an action potential

Answer 15

remains the same no matter how intense the stimulus is

Question 16

changing the stimulus intensity & action potentials

Answer 16

affects the rate of firing

Question 17

ions

Answer 17

molecules that carry an electric charge

Question 18

where is Na+ most concentrated

Answer 18

outside the axon

Question 19

where is K+ most concentrated?

Answer 19

inside the axon

Question 20

permeability

Answer 20

the ease with which a molecule can pass through the membrane

Question 21

depolarization

Answer 21

an increase in positive charge inside the neuron

Question 22

what causes depolarization

Answer 22

an inflow of positively charged sodium ions

Question 23

hyperpolarization

Answer 23

an increase in the negative charge inside the neuron

Question 24

what causes hyperpolarization

Answer 24

the rush of positively charged potassium ions out of the neuron

Question 25

sodium-potassium pump

Answer 25

continuously pumps sodium out and potassium into the neuron to maintain the resting potential

Question 26

synapse

Answer 26

the small space between neurons

Question 27

neurotransmitter

Answer 27

chemical messengers that are stored in synaptic vesicles

Question 28

excitatory response

Answer 28

When the neuron becomes depolarized and the inside of the neuron becomes more positive

Question 29

inhibitory response

Answer 29

when the neuron becomes hyperpolarized and the inside of the neuron becomes more negative

Question 30

sensory coding

Answer 30

how neurons represent various characteristics in the environment

Question 31

specificity coding

Answer 31

a specialized neuron that responds only to one concept or stimulus

Question 32

grandmother cell

Answer 32

another word for specificity coding

Question 33

quiroga neural representation study

Answer 33

in patients undergoing brain surgery for epilepsy, some neurons responded to many ways of representing a person or building

Question 34

sparse coding

Answer 34

when a particular stimulus is represented by a pattern of firing of only a small group of neurons, with the majority of the neurons remaining silent

Question 35

population coding

Answer 35

our experiences are represented by the pattern of firing across a large number of neurons

Question 36

phrenology

Answer 36

observing the skull to determine an individual’s psychological attributes

Question 37

modularity

Answer 37

specific brain areas are specialized to respond to specific types of stimuli or functions. Made evident by Broca’s & Wernicke’s areas

Question 38

broca's area

Answer 38

an area in the left frontal lobe responsible for speech production

Question 39

wernicke's area

Answer 39

an area in the temporal lobe involved in understanding speech

Question 40

neuropsychology

Answer 40

relating the location of brain damage to specific effects on behaviour

Question 41

brain imaging

Answer 41

recording brain responses to create pictures of the location of the brain’s activity

Question 42

Magnetic Resonance Imagining (MRI)

Answer 42

a technique used to reveal brain structures

Question 43

Functional Magnetic Resonance Imaging (fMRI)

Answer 43

enables researchers to determine how various types of cognitions activate different areas of the brain

Question 44

how do fMRIs work?

Answer 44

Takes advantage of the fact that blood flow increases in activated brain areas. Hemoglobin, which carries oxygen in the blood contains a ferrous molecule and has magnetic properties

Question 45

voxels

Answer 45

small cube-shaped subdivisions of the brain

Question 46

reading an fMRI

Answer 46

Hotter colours indicate higher activation and cooler colours indicate lower activation. Coloured areas represent the difference between the task-related and resting-state fMRI

Question 47

Task-related fMRI

Answer 47

the fMRI measured when a person is engaged in a specific task

Question 48

resting-state fMRI

Answer 48

the fMRI measured when the brain is not involved in a specific task

Question 49

distributed representation

Answer 49

Occurs when a stimulus causes neural activity in several different areas of the brain, so the activity is distributed across the brain

Question 50

structural connectivity

Answer 50

the road map of fibres connecting different areas of the brain

Question 51

functional connectivity

Answer 51

the neural activity associated with a particular function that is flowing through this structural network

Question 52

measuring resting state functional connectivity

Answer 52

1. Use task-related fMRI to determine the seed location: brain location associated with carrying out a specific task 2. Measure the resting-state fMRI at the seed location 3. Measure the resting state fMRI at another location, called the test location 4. Calculate the correlation between the seed and test location responses

Question 53

functional vs. structural connections

Answer 53

Just because two areas are functionally connected doesn’t mean that they are structurally connected (directly communicate by neural pathways). But, they are related; regions with high structural connectivity often have high functional connectivity

Question 54

the mind-body problem

Answer 54

How do physical processes become transformed into the richness of perceptual experience?

Question 55

what kind of problem is the mind-body problem

Answer 55

causational

Question 56

Selective

Answer 56

The fibre is permeable to one specific type of molecule

Question 57

how long does an action potential last

Answer 57

1ms

Question 58

basic properties of action potentials

Answer 58

- Propagated response - Remain the same size regardless of stimulus intensity - Increase in rate to increase in stimulus intensity - Have a refractory period of 1 ms - Upper firing rate is 500-800 impulses per second - Show spontaneous activity that occurs without stimulation

Question 59

when are electrical signals generated in neurons?

Answer 59

when ions cross the membranes of neurons

Question 60

the release of neurotransmitters

Answer 60

by the presynaptic neuron from vesicles. Received by the postsynaptic neuron on receptor sites. Matched, like a key to a lock, into specific receptor sites. Used as triggers for voltage change in the postsynaptic neuron

Question 61

ways to activate receptors

Answer 61

Membrane deformation Voltage gated Neurotransmitter gated

Question 62

how can modularity be studied?

Answer 62

by recording brain responses in neurologically normal humans using brain imaging, making it possible to create pictures of the location of the brain’s activity

Question 63

what does the distributed approach focus on?

Answer 63

the activity in multiple brain areas and the connections between those areas