Neuromodulation & Plasticity

Question 1

How do neuromodulators act?

Answer 1

1. Change intracellular Ca2+ to trigger specific Ca2+ regulatory enzyme systems
2. Activate specific G-Proteins that couple to the activation or inhibition of different enzyme cascades

Question 2

What is en passant atypical synaptic connection?

Answer 2

Synapsing onto other synapses

Question 3

Name the primary neuromodulatory molecule for the following classes:

• Cholinergic
• Catecholamines
• Indoleamines
• Neuropeptides

Answer 3

• ACh in the CNS
• Dopamine in the CNS
• Serotonin
• Many - released to change system state or regulate pain

Question 4

How are peptide transmitters synthesized?

Answer 4

Into vesicles in ER as inactive precursors

Question 5

Where in the neuron are neuropeptides synthesized?

Answer 5

soma

Question 6

What is neuroplasticity?

Answer 6

Changes in nervous system function, revealed as changes in neuronal firing in response to same stimulus - underlies changes in Learning & Memory

Question 7

Changes in learning and memory and plasticity can be directly related to_____

Answer 7

pattern of preceding experiences

Question 8

Two main classes of plasticity:

Answer 8

1. Excitability- Changes in Likelihood of firing Action Potentials in response to the same stimuli
2. Synaptic- Changes in the strengths of connections between neurons

Question 9

What receptor is a classic example for coincidence detection?

Answer 9

NMDA receptor

Question 10

What blocks the NMDA receptor from conducting at negative potentials? What relieves the blockade?

Answer 10

Extracellular Mg2+ blockade

Relieved by depolarization to positive potential, opening channel conduction

Question 11

Hebbian Plasticity Rules

Answer 11

• If synaptic inputs from neuron A contribute to the firing of the post-synaptic neuron B, then the connection from A to B will be strengthened
• If synaptic inputs from neuron A are not associated with the firing of post-synaptic neuron B, then the connection from A to B will be weakened.

Question 12

Plasticity in what part of the brain is important for learning and memory?

Answer 12

Hippocampus

Question 13

What is spike timing plasticity?

Answer 13

Presynaptic Cell fires AP before Post-synaptic cell- Connection Strengthens

Postsynaptic Cell fires AP before Presynaptic cell- Connection Weakens

Question 14

Pairing Synaptic activity with ____________Strengthens Synapses

Answer 14

Post-synaptic Depolarization

Question 15

Long-term potentiation results in growth of dendritic____ and insertion of new _______ receptors

Answer 15

Spines

Glutamate receptors

Question 16

NMDA Receptor Ca2+ Influx Triggers ______ Activation

Answer 16

CamK2

Question 17

Following LTP, _____ receptors are inserted into the Post-Synaptic membrane

Answer 17

AMPA

Question 18

Repetitive synaptic stimulation without action potential firing ______ synaptic strength.

Answer 18

weakens

Question 19

The hippocampal and cerebellar LTD stimulation paradigm cause _____ of AMPA receptors, weakening synaptic strength. How is the mechanism different in cerebellar?

Answer 19

internalization

Cerebellar - does so in a protein kinase dependent manner

Question 20

Cerebellar function depends critically on _______ modulation of parallel fiber synapses

Answer 20

Climbing fiber

Question 21

What do climbing fibers carry?

Answer 21

Error signals used to suppress granule cell synapses that are active at the same time as the climbing fiber

Question 22

Cerebellar LTD uses Ca2+ signaling, but is produced by activation of ____

Answer 22

Kinases

Question 23

What is inhibitor for mvts in cerebellar LTD?

Answer 23

Purkinje output

Question 24

If parallel fibers are driving Purkinje cells excessively, _____ send a correction signal to reduce synaptic efficacy of active synapses

Answer 24

Climbing fibers

Question 25

Granule cell synapses weaken when their activity is paired with ______

Answer 25

climbing fibers