1
Q
Explain the function of sensory nerves (1)
A
- Carry information from the body’s peripheral sensors into the nervous system for the purpose of both perception and motor coordination
- Are also known as afferent neurons
2
Q
What sensory properties does our skin have? (6)
A
- Pain
- Pleasure
- Touch
- Itching
- Heat
- Vibration
3
Q
What are somatic receptors and give 3 examples of somatic receptors.
A
- A subgroup of sensory receptors involved in different sensory perception.
- Located in the skin, muscle bones, and joints
EXAMPLES
Mechanoreceptors - touch and proprioception
Nociceptors - pain
Thermoreceptors - temperature
4
Q
Receptor potential from short mechanoreceptors spread ______ from the _________ region to the ________ pole.
This action (does/does not) require an action potential
A
passively; sensory; synaptic; does not
5
Q
Receptor potential from long mechanoreceptors can generate _________ and gives information about _______ and ______ of the original stimulus.
A
Action potentials; duration or intensity
6
Q
Describe the course of action potential frequency in slowly and rapidly adapting receptors. What is receptor MRO1? What receptor is MRO2?
A
Slow adapting receptors
- Weak stretch produces a series of action potential
- MRO1
Fast adapting receptors
- Action potential frequency declines over time during long stretch (receptro potential is not maintained)
- MRO2
7
Q
What kind of signals are recorded during intracellular recording? (2)
A
Afferent nerve: retrograde signals
Efferent nerve: anterograde signals
8
Q
Explain the process to dissect a crayfish, leaving only the superficial extensors on the crayfish for experimentation.
A
- Remove head
- Remove ventral part of the shell by cutting close to ventral surface
- Remove deep-flexore muscles with hand
- Attach a thread to the tail
9
Q
How can we obtain a high signal-to-noise ratio when performing extracellular recording?
A
- Getting the best possible recording (high signal)
- Decreasing the noise reaching the electrode (low noise)
- Electronically removing noise that reaches the amplifier (filtering)
10
Q
What are muscle receptor organs?
A
- Stretch-sensitive proprioceptors that help track the positioning of body parts
- Broader category: somatic receptors
11
Q
What are the functions of exteroceptors? (3)
A
Touch, temperature, pain
12
Q
What is the function of enteroceptors? (1)
A
Regulation of internal processes
- Respiration
- Thirst
- Hunger
- blood pressure
13
Q
What is neuroplasticity?
A
The ability of neurons and neuronal networks to change or adapt de to experience
E.g.
- Learning a new ability
- Neuronal damage/dysfunction
- Information acquisition
- Environmental influence
14
Q
What are two types of plasticity?
A
Functional plasticity: transfer functions from an impaired region to unaffected areas
Structural plasticity: alter physical structure in response to the process of learning
15
Q
What types of learning are there? (2)
A
- Associative learning
- Behavioural change by formation of associations between events or two stimuli
- Classical conditioning (involuntary)
- Operant conditioning (voluntary) - Non-associative learning
- Behavioural change due to experience with particular stimuli
- Habituation (negative memory)
- Sensitization ( positive memory)
16
Q
Why are Aplysias used as animal models in electrophysiology? (5)
A
- Short life span (~ 1 year)
- Simple nervous system
- Large nerve cell bodies (largest reaches up to 1mm)
- Little variation (consistent location of individual neurons between groups)
- Capable for various behaviours and simple learning
17
Q
What is short-term habituation and its mechanism?
A
Habituation is a process that causes the animal to become less responsive to repeated occurrences of a stimulus.
- Occurs due to activity-dependent presynaptic depression of synaptic transmission
- Quantal release of glutamate decreases from the presynaptic terminals of sensory neurons
18
Q
What are three falsified theories of habituation and how are they proven false?
A
- Muscle fatigue
- Reflex response remained constant throughout when strong stimulus applied - Motor synapse fault
- Stimulation of motor neuron after habituation of Aplysia elicited nonhabituated response - Skin sensitivity
- Blocking of signals to the sensory neuron when Aplysia is habituated yields recovery despite skin being stimulated even when nerve block occurred.
19
Q
What are 5 examples of bad trials during the habituation experiment?
A
- Natural movements or reflexes
- Responses to water movement, such as shaking a table, or reactions to shadows
- You touched a different part of the siphon/body
- Double pump (siphon/gill)
- Variations in the intensity or speed of touching the siphon, whether too strong, too weak, very fast, or very slow.
20
Q
What are some good notes to take during an Aplysia experiment? (4)
A
- If aplysia inks
- If aplysia is non-responsive
- If an aplysia laid eggs
- If you missed a trial, had a problem, any other issues
21
Q
Explain the pathway of neuronal signals in a reflex response
A
- Sensory signals
- Only signal that is affected stimulus and have a graded receptor potential in this pathway - Motor signals
- Uses graded synaptic potential - Muscle signals
- Uses graded synaptic potential
22
Q
What can affect the extent of sensitization in aplysias? (3)
A
- Age of the animal
- Intensity of the stimulus
- Frequency of the exposure of the stimulus
23
Q
What type of cellular receptros are associated with serotonin binding? (2)
A
- Channel linked
- ion channels - GPCR
24
Q
Explain the pathway for short- and long-term sensitization
A
Short-term
1. Noxious stimulus to tail
2. Release of serotonin in through serotonergic modulatory neurons
3. Stimulated GCPR activated for cascade effect through effectors (e.g. cAMP)
- Actiaved PKA prevents outflow of K+ and helps influx of Ca+2
Long-term
4. PKA enters nucleus and activates CREB (promoter)
5. CREB recruite other transcription proteins to transcript target gene
6. Transcribed gene causes synaptic plasticity
7. Ubiquitinhydrogolase increase cAMP in sennory presynaptic
25
What is the defining contributor to short-term and long-term sensitization.
Short-term: serotonin upreguulates cAMP and PKA in sensory nerve terminal for more glutamate release.
Long-term: Requires new nuclear gene expression and protein synthesis. Caused by repeated activation of serotonergic modulatory neurons.
26
What differs from LTP and LTD?
LTP - long-term increase in synaptic strength through insertion of additional AMPA receptors
LTD - long-term decrease in synaptic strength through internalization of AMPA receptors
27
What type and dosage of current is injected to Aplysia when delivering an electrical stimulus during the sensitization experiment?
- 60-100mA
- DC current
28
How large should the sample size be for a standard scientific experiment and why? (3)
- A standard scientific experiment should have at least 3 samples per group
- Ensures statistical reliability of experiment
- Control for differences in experimental outcomes
a. Differences in animal physiology
b. Variations in experimental procedure
c. Setup configurations
29
How can we calculate for the change in response over time in a habituation and sensitization experiment?
|Initial Response Time - Final Response Time|/Initial Response Time *100
(Increase in response = Initial
30
What kind of cells and their emotional responses influenced by emotional stimuli? (3)
Skeletal muscle -> (voluntary) behaviour
Smooth or cardiac muscle -> Auntonomic activity
Endocrine gland -> hormonal release
31
How can acetylcholine regulate blood pressure?
Acetylcholine release in endothelial cells cause rapid relaxation of smooth muscle cells through nitric oxide (NO).
- Increases blood flow
32
Who is John Harlow? Explain his notable case study.
- A physician that emphasized the connection between distinct brain regions and various psychological behaviours.
- Case study: Phineas Gage
- Damage to frontal lobe cause changes in his personality
33
What are 6 psychological methods?
1. Electroencephalography (EEG): Which measures electrical activity in the brain and is often used
to study sleep, cognition, and neurological disorders.
2. Functional Magnetic Resonance Imaging (fMRI): Which measures brain activity by detecting
changes associated with blood flow and is used to understand brain function and structure.
3. Electrocardiography (ECG): Which records the electrical activity of the heart and can be used to
study the effects of psychological states on cardiac function.
4. Galvanic Skin Response (GSR): Which measures changes in sweat gland activity that are
reflective of the intensity of our emotional states.
5. Electromyography (EMG): Which records electrical activity produced by skeletal muscles and can
indicate the level of muscle tension due to emotional or psychological stress.
6. Eye Tracking: Which monitors the movement and dilation of the pupils, providing insight into
attention and arousal.
34
What EMG reveal in a health context?
Health of muscles and the nerve cells that control them
- Nerve dysfunction
- muscle dysfunction
- Nerve-tomuscle signal transmission
35
How can strength be operationalized?
- Thicker muscle fibers/skeletal muscle cells
- More myofirbrils
- More ATP and glycogen
36
What is a motor unit and how do different type motor units differ in force?
Motor unit: All the muscle fibers innervated by a single nerve fiber
Force: Fast fatigable > Fast fatigue-resistant > Slow
Time of force: Slow > Fast fatigue-resistant > Fast fatigable
37
What are 2 ways summation occurs (muscle)?????
1. Multiple fiber summation
- Many different motor units fire at the same time
2. Frequency summation
- Same motor unit firing frequency
38
What happens to the contractile force after in a denervated muscle vs myopathy?
Myopathy: Decreased contractile strength
Denervated muscle: Increased contractile strength
39
What is a treatment to myasthenia gravis (fewer ACh receptors)?
10 mg of edrophonium injection because it is an acetylcholinesterase inhibitor
- Extends ACh's duration in synaptic cleft to offset effect of fewer ACh receptor
40
Who should NOT participate in stimulating electrodes experiment?
- Participants with cardiac pacemakers or neurological or cardiac disorders
41
What are the applications of psychophysiological methods in psychology and neuroscience? (2)
- Sleep and cognitive studies
- emotion research
42
What are the applications of psychophysiological methods in clinical setting? (1)
- Diagnose mental health disorders
43
What are the applications of psychophysiological methods in human-computer interaction? (2)
- marketing and consumer research
- Education application
44
What is an advantage and limitation to EEG recording?
Advantage: its great simplicity.
Limitation: poor spatial resolution because
electrodes separated from brain by scalp, skull,
cerebrospinal fluid, etc.
45
What signals are recorded by EEG? (4)
- Small EPSP
- Spatial summation of EPSPs
- Temporal summation of EPSPs
- Summed EPSP + IPSP
(Very little contribution comes from AP propagating along nerve axons)
46
What type of signal is detected when awake with eyes open? What is the frequency and amplitude of signal?
- Beta activity
- 13-80 Hz
- <20 µV.
47
What type of signal is detected when awake with eyes closed? What is the frequency and amplitude of signal?
- Alpha waves
- 8-13 Hz
- 30-50 µV
48
What type of signal is detected when in Stage 1 sleep? What is the frequency and amplitude of signal?
- Theta waves
- 4-8 Hz
- <30 µV
49
What type of signal is detected when in Stage 2 sleep? What is the frequency and amplitude of signal?
- Sleep spindles
- 10-12 Hz
- 50-150 µV
50
What type of signal is detected when in Stage 3/4 sleep? What is the frequency and amplitude of signal? µV
- Delta waves
- 0.5 - 4 Hz
- 100 - 200 µV
51
What type of signal is detected when in REM sleep? What is the frequency and amplitude of signal?
- Alpha waves
- 8 - 13 Hz
- 30 - 50 µV
(Low-voltage, high-frequency)
52
What are some trends during sleep?
As sleep deepens in slow-wave or REM
- eye and head movement becomes less prominent
- Heart rate and respiration decreases
REM
- Increase in heart rate and respiration
- Neck movement occurs just before and after
During sleep
- (verbal) movements occur during non-REM
- Nightmares occur during REM
53
Where are EEG electrodes placed?
+ -> inion
- -> forehead
54
Explain the function of High Pass and Low Pass on the Bio Amp.
High Pass: Filters and excludes any signals below setting
Low Pass: Filters and exludes and signals above setting
55
What are 3 challenges and expectations in EEG recordings?
- Avoid crowed spaces for EEG to minimize interference
- Setting should be quiet and participant in a lying position
- Proper placement of electrodes for quality signals
56
Where are different brainwaves typically found? (3 <- exlude delta waves)
Alpha: Occipital region (but can be recorded from parietal and frontal)
Beta: Parietal and frontal region
Theta: Parietal and temporal for awake children; occurs during emotional stress in adults
57
What is the purpose of spectrum analysis?
- Represent data on the frequency distribution of its component sine waves
- Allow observation of frequency distribution to determine component of EEG waveform data (alpha, beta, theta, delta)
58
What are artifacts in EEG?
- A range of unwanted interfering influences
- Essentially noise to experiment
59
How is the skeletal muscles attached to the skeleton? (3)
- Tendons (strong bundles of collagen fibers)
- Aponeuroses (flat, sheet like tendons)
- Fascia (bands of connective tissue)
60
Explain the activation process of a contraction. (4)
1. initation of an action potential (voluntary or stimulation)
2. Conduction of AP along nerve fiber
3. Release of ACh at the neuromuscluar junction
4. Deplarization of muscle membrane -> contration
61
What does the root mean square method of recording?
- Processing raw EMG signals by squaring averaged squared signals to indicate intensity of EMG activity
- Smoothes out individual spikes and make analysis of the time course of changing activity clearer
62
What can nerve condution velocity indicate about an invididual? What is the equation for nerve conduction velocity?
- Normal nerve conduction is ~ 50 - 50 m/s
- Abnormality may indicate a nerve and muscle disorder
Velocity = Distance between stimulation sites/Difference between latencies
63
What features are 3 superficial branch of nerve 3?
- Contains only 6 axons and shows spontaneous activity with easily distinguisable action potential classes
- All axons are from motor neurons
- Range of axon diameters therefore action potentials of different amplitudes
64
How can different neurons be discriminated with an extracellular recording?
Amplitudes of action potential differ due to differences in diameter of axon (influence velocity of conductance)
65
What are spontaneous activities and how can we analyze them?
Spontaneous activity is a single-unit activity in one motor nerve that fire in the absence of excessive electrical noise.
We can observe spontaneous activity when distinct amplitudes of action potentials are repeatedly observed
66
What is reflex activity and how can we observe them in extracellular recording?
These are patterns of activity that are altered through activation of reflexive responses.
Determine reflexive activity by comparing stimulated responses with unstimulated activity. Any changes from unstimulated activity is classified as a reflexive activity
67
What is reflex activity and how can we observe them in extracellular recording?
These are patterns of activity that are altered through activation of reflexive responses.
Determine reflexive activity by comparing stimulated responses with unstimulated activity. Any changes from unstimulated activity is classified as a reflexive activity
68
What is the formula for firing rate (SPM) and firing frequency (Hz)
Rate (SPM) = (n-1)/(difference in time)*60
Frequency (Hz) = Rate/60
69
Define neurophysiology.
Neurophysiology is the study of the nervous system's functions, and one of its focuses is on the sensory and motor system.
Focus: sensory and motor system, synaptic transmission, nueral circuits
70
How are microelectrodes prepared for extracellular recording? Why are they prepared like this?
- Break microelectrode with a coarse foreceps
- Use a torch lighter to polish pipette
- Examine under microscope to ensure size fits target axon bundle
- This creates optimal seal between nerve and glass pipette to ensure no leak
- Prevents noise
71
3 Key features required to do an extracellular recording.
- Ensure saline reaches wire inside the tube
- Ensure external wire of electrode is in saline to complete circuit
- Small loop of the nerve is sucked into the tip
72
Considerations for extracellular recording
No recording or extremely high noise:
- Saline not reach internal wire
- Ground wire not in saline
Excessive force to suck nerve into electrode:
- Pipette tip too small -> clogged
- Tubing between electrode and syringe is bent
Suction won't hold
- Pipette tip too large or not firmly placed on the electrode holder
Weak recording or no action potential:
- Pipette tip is too large for the nerve
- Solution: press tip against some other surface or suck nerve with other debris
73
3 Considerations when working with animal experiments
- Constant challenges with biological samples
- In vivo experiment deviate from theoretical expectations
- Common to get inconclusive data
-
Key Links
-
Subjects
-
Company
-
Find Us
-
