Neurophysiology

Question 1

Most synapses are tripartite. What does this mean?

Answer 1

Most synapses consist of 3 components.

Question 2

What are the 3 components of a synapse?

Answer 2

Presynaptic terminal.
Postsynaptic terminal.
Glial cell.

Question 3

How do astrocytes modulate synaptic behaviour?

Answer 3

The NTs released from neurons also bind to receptors on the adjacent astrocyte process, activating signalling pathways in the astrocytes.

Question 4

What is the structure of a sensory neuron?

Answer 4

Pseudo-unipolar cell body.
Branched dendrite myelinated by Schwann cells.
Central projection that branches in the spinal cord.
Surround by a satellite cell.
Few synapses.

Question 5

What is the role of the central projection of a sensory neuron?

Answer 5

Innervates motor neurons directly and indirectly via interneurons.

Question 6

What is the structure of an interneuron?

Answer 6

Short unipolar axon.
Short dendrites.
Limited number of synapses.

Question 7

Which types of neurons provide input to lower motor neurons?

Answer 7

Sensory neurons either directly or via interneurons.
Descending upper motor neurons.

Question 8

Where do inputs occur on a motor neuron?

Answer 8

Largely on dendrites in a large dendritic field.
Also on the cell body and axon.

Question 9

What type of receptor is an NMDAR?

Answer 9

Ionotropic glutamate receptor.

Question 10

What type of receptor is an AMPAR?

Answer 10

Ionotropic glutamate receptor.

Question 11

What type of receptor is an MGluR?

Answer 11

Metabotropic G-protein coupled glutamate receptor.

Question 12

What type of receptor is GABAa?

Answer 12

Ionotropic receptor.

Question 13

What type of receptor is GABAb?

Answer 13

Metabotropic receptor.

Question 14

What is the role of NMDAR and AMPAR?

Answer 14

Mediate fast synaptic transmission.

Question 15

What is the role of MGluR?

Answer 15

Mediate slow neuromodulatory effects.

Question 16

What is the role of GABAa?

Answer 16

Mediate fast inhibition.

Question 17

What is the role of GABAb?

Answer 17

Mediate slow synaptic inhibition.

Question 18

What are some antagonists of AMPAR?

Answer 18

CNQX.
NBQX.

Question 19

What are some antagonists of NMDAR?

Answer 19

AP5.
AP-7.

Question 20

What are some channel blockers of NMDAR?

Answer 20

Magnesium ions.
Phencyclidine.
Ketamine.
MK801.

Question 21

What does psychophysics mean?

Answer 21

The physical characteristics of a stimulus related to mental sensation.

Question 22

What does sensory physiology mean?

Answer 22

The mapping of how stimuli are transduced by sensory receptors and processed in the brain.

Question 23

What is the neuronal firing pattern of a slowly adapting receptor?

Answer 23

Starts at the point of the stimulus and then gradually slows down.

Question 24

What is the neuronal firing pattern of a rapidly adapting receptor?

Answer 24

Starts at the point of the stimulus and then adapts rapidly and stops firing.

Question 25

What do slowly adapting receptors signal?

Answer 25

A stimulus is constant.

Question 26

What do rapidly adapting receptors signal?

Answer 26

A stimulus has changed.

Question 27

What are relays?

Answer 27

Successive levels in the neuronal network.

Question 28

What are the two roles of relays?

Answer 28

1. Allow integration of information across spatial and temporal domains.
2. Allow top-down selection of or attention to stimuli through neuromodulation.

Question 29

What is an example of top-down neuromodulation?

Answer 29

When listening to a piece of music, we are able to isolate the melody of the violin from the melody of the piano.