Questions for Action Potential Conduction Velocity Lab and Statistical Analysis
Where does an action potential first appear in a neuron? Why here?
Where are the cell bodies of somatic motoneurons located and through what structures do their axons
pass on the way to their synapse with a skeletal muscle cell?
What are the various names for the synapse between a motoneuron and a skeletal muscle cell?
Which neurotransmitter used at this synapse?
What type of receptor is found on skeletal muscle cells?
How does Ca++ enter the presynaptic terminal? What are the directions of the driving forces?
What role does Ca++ play in synaptic transmission?
What events contribute to the phenomenon known as synaptic delay?
What types of axons are found in the ulnar nerve?
Why are touch and proprioception considered together when describing ascending pathways to the
brain?
Why are pain and temperature considered together when describing ascending pathways to the brain?
What is proprioception?
Where are the cell bodies of first order sensory neurons involved in touch or proprioception located?
Where are the cell bodies of first order sensory neurons involved in pain or temperature located?
By what structure do afferent axons enter the spinal cord?
Some proprioceptive axons form synapses directly on somatic motoneurons. Is this configuration
called monosynaptic or polysynaptic?
A branch of the proprioceptor or touch axon joins the white matter in which region of the spinal cord?
Where does that axon go and where does it form a synapse onto a second order sensory neuron?
Where do second order sensory neurons in the touch and proprioception pathway send their axons?
Do these axons decussate?
Third order sensory neurons are located in what part of the brain? Where do these third order sensory
neurons send their axons?
What is the region of the brain called that processes sensory information from various parts of the
body?
How is it that a touch stimulus delivered to the left hand gets processed on the right side of the brain?
For a first order sensory neuron axon conveying pain or temperature information, what is the location
of the second order sensory neuron’s cell body?
At what location do pain and temperature pathways cross the midline of the central nervous system?
What is the name of the group of axons (tract) within the spinal cord that pain and temperature axons
ascend upward toward the brain? Where is this tract located?
Where are third order neuronal cell bodies located in the pain and temperature pathway?
Of what use is this knowledge about the routes by which the various sensory modalities pass from the
spinal cord to the brain?
What is an electromyogram (EMG)?
What is a compound action potential?
Why doesn’t a compound action potential have the same shape as an action potential recorded with a
pair of electrodes, with one of those electrodes inside the cell?
How long is an action potential in a neuron?
Why is the compound action potential so much longer in duration than an intracellular AP?
Why did we use the ulnar nerve for our experiments?
Why was it necessary to make two sets of recordings, one of EMGs produced by stimulation at the
elbow and the other by stimulation at the wrist?
In order to calculate conduction velocity in the ulnar nerve, was it necessary to know the duration of
synaptic delay?
Why is it difficult to describe the sensation produced by transcutaneous electrical stimulation of the
ulnar nerve?
If the transcutaneous stimulus is uncomfortable or mildly painful, what aspect of the stimulus can be
modified to reduce the irritation?
When would one opt to use the Scope program for the PowerLab?
When would one opt to use the Chart program for the Powerlab?
What should be done if the recording is larger than the vertical axis of the Scope recording?
Why was it necessary to “overlay the stimulus” onto Channel A?
What are the potential sources of error that contribute to variability in the measurement of action
potential conduction velocity (AP CV)?
What can be done to the skin to improve its conductivity to electricity?
For some people, especially men with muscular arms, it may be difficult to transcutaneously stimulate
the ulnar nerve at the elbow or wrist. Explain why?
Based on our experiments in lab, are there any differences in AP CV in human ulnar nerves based on
gender?
Is AP CV faster in dominant arms?
Is AP CV faster in weightlifters compared to non-weightlifters?
Suppose the mean AP conduction velocity in the ulnar nerve for male hamsters was 54 m/sec and for
females hamsters was 56 m/sec and the p value from a T-test was 0.03. Is there a difference in the
conduction velocity based on the sex of hamsters? Defend your answer.
A visual evoked potential test has the subject stare at a screen upon which an alternating checkerboard
pattern was flickering. What is measured in this test and what can the results reveal?
An auditory evoked potential test would have a subject wear headphones through which a series of
clicks is played. What is measured in this test and what can the results reveal?
What neurological disorder is characterized by a loss of myelin and how is action potential conduction
affected by demyelination or dysmyelination?