MCB 170: Neuron Synaptic Plasticity

What does plasticity mean?

What does plasticity mean?

the capacity of the nervous system to change

What are the spatial features of synaptic plasticity?

at synapses, within neurons, and within glial

What is plasticity the foundation of?

learning + memory and recovery from injury or disability

What is important about LTP in the hippocampal CA1?

high frequency electrical stimulation of excitatory pathway produces LTP

What is LTP determined by?

specificity and associativity

What does specificity mean when it refers to LTP?

only active synapses are strengthened

What does associativity mean when it refers to LTP?

co-active synapses are strengthened

What are the two glutamate-gated cation channels?

AMPA and NMDA

What is important to know about NMDA?

• voltage-gated owing to the action of Mg²+

• conducts Ca²+

True or False: Glutamate receptors mediate excitatory synaptic transmission.

true

What triggers second messenger systems?

high amounts of intracellular C²+

What are the molecular mechanisms of LTP?

1. High amounts of Ca²+ triggers second messenger systems

2. Kinases are activated

3. Phosphorylation of AMPA receptors to increase Na^+ conductance

4. Insertion of additional AMPA receptors

What is a silent synapse?

a synapse in which an excitatory postsynaptic response is absent at the resting membrane potential but becomes apparent on depolarization

Which receptor is present in a silent synapse?

NMDA

How can a silent synapse mature?

developmentally regulated or by LTP

What does internalization of AMPA receptors refer to?

AMPA receptors are removed from the post synaptic membrane and transported into the cell

True or False: Activity of presynaptic neurons triggers activation of second messenger systems by altering the level of intracellular Ca²+ in post synaptic neurons.

true

What alters the activity of protein kinases and phosphatases?

Ca²+ dependent second messenger systems

What is early stage changes of synaptic plasticity mediated by?

alterations of protein phosophorylation

What is late stage changes in synaptic strength mediated by?

alterations of gene expression

What is Hebb’s postulate?

coordinated activity strengthens the synaptic connection between them, and uncoordinated activity weakens the synaptic connection between them

True or False: Changes at the synaptic level can produce changes in the wiring patterns of neural circuits.

true

What type of plasticity is associated with postnatal life?

experience-dependent plasticity

When are changes in synaptic connections the most profound?

development/postnatal life

What is the critical period?

a time during early postnatal life when the development and maturation of functional properties of the brain occur

What happens to synaptic connections during a critical period?

correlated patterns of activity are thought to mediate critical periods by stabilizing concurrently active synaptic connections and weakening or eliminating connections whose activity is divergent

How do we know there is a critical period?

the complete absence of certain experiences during critical periods prevents the development of associated brain functions