Neuromodulation & Plasticity Flashcards
How do neuromodulators act?
- Change intracellular Ca2+ to trigger specific Ca2+ regulatory enzyme systems
- Activate specific G-Proteins that couple to the activation or inhibition of different enzyme cascades
What is en passant atypical synaptic connection?
Synapsing onto other synapses
Name the primary neuromodulatory molecule for the following classes:
- Cholinergic
- Catecholamines
- Indoleamines
- Neuropeptides
- ACh in the CNS
- Dopamine in the CNS
- Serotonin
- Many - released to change system state or regulate pain
How are peptide transmitters synthesized?
Into vesicles in ER as inactive precursors
Where in the neuron are neuropeptides synthesized?
soma
What is neuroplasticity?
Changes in nervous system function, revealed as changes in neuronal firing in response to same stimulus - underlies changes in Learning & Memory
Changes in learning and memory and plasticity can be directly related to_____
pattern of preceding experiences
Two main classes of plasticity:
- Excitability- Changes in Likelihood of firing Action Potentials in response to the same stimuli
- Synaptic- Changes in the strengths of connections between neurons
What receptor is a classic example for coincidence detection?
NMDA receptor
What blocks the NMDA receptor from conducting at negative potentials? What relieves the blockade?
Extracellular Mg2+ blockade
Relieved by depolarization to positive potential, opening channel conduction
Hebbian Plasticity Rules
- 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.
Plasticity in what part of the brain is important for learning and memory?
Hippocampus
What is spike timing plasticity?
Presynaptic Cell fires AP before Post-synaptic cell- Connection Strengthens
Postsynaptic Cell fires AP before Presynaptic cell- Connection Weakens
Pairing Synaptic activity with ____________Strengthens Synapses
Post-synaptic Depolarization
Long-term potentiation results in growth of dendritic____ and insertion of new _______ receptors
Spines
Glutamate receptors
NMDA Receptor Ca2+ Influx Triggers ______ Activation
CamK2
Following LTP, _____ receptors are inserted into the Post-Synaptic membrane
AMPA
Repetitive synaptic stimulation without action potential firing ______ synaptic strength.
weakens
The hippocampal and cerebellar LTD stimulation paradigm cause _____ of AMPA receptors, weakening synaptic strength. How is the mechanism different in cerebellar?
internalization
Cerebellar - does so in a protein kinase dependent manner
Cerebellar function depends critically on _______ modulation of parallel fiber synapses
Climbing fiber
What do climbing fibers carry?
Error signals used to suppress granule cell synapses that are active at the same time as the climbing fiber
Cerebellar LTD uses Ca2+ signaling, but is produced by activation of ____
Kinases
What is inhibitor for mvts in cerebellar LTD?
Purkinje output
If parallel fibers are driving Purkinje cells excessively, _____ send a correction signal to reduce synaptic efficacy of active synapses
Climbing fibers
