Activity dependent refinement of synaptic connections Flashcards
What is “the critical period” in brain development?
The critical period contains both the excess formation of synapses and synapse elimination. This happens at the same time (reorganization).
The critical period is important for creating the required networks, but it is also more vunerable, and there is an increased risk for developing neurological disorders in this period.
What is Hebb’s postulate?
‘Neurons that fire together wire together’
How is the NMDA receptor contributing to the fact that “Neurons that fire together wire together”?
NMDA receptors are often not active at resting membrane potential, but if the cells are activated at same time (pre and post synaptic) the NMDA allow influx of ions, that strengthens the signaling.
What are the effect of synchronous vs asynchronous firing in two connected neurons?
If the firing is synchronous, the connection will become stonger, and the opposite will happen if it is asynchronous
What cognitive functions are most dependent on synaptic organization?
The higher cognitive functions (shapen specificity, function that require reacting to external stimuli)
What does an immature pre and postsynaptic terminal look like?
The presynaptic terminal will have less efficient transmitter release, and the postsynaptic terminal will have less or a different type of neurotransmitter receptors
What is a silent synapse?
A synapse with hardly any receptors, and no excitatory postsynaptic current at resting membrane potential
What is Hebbian plasticity?
The idea that the presynaptic terminal stimulating the postsynaptic spine will increase their connection.
Often explained in relation to long-term potentiation (LTP) or long-term depression (LTD)
What happens to the amount of AMPA receptors in the postsynaptic spine during LTP and LTD
With LTD there is a loss of synaptic AMPA receptors.
With LTD there is an insertion and/or stabilization of AMPA receptors.
What causes spontaneous activity in neurons before synapse formation?
Calcium spikes
What cellular structure is important for early network oscillations?
Gap-junctions between neurons
What comes after early network oscillations in the developing brain?
Cortical giant depolarizing potentials, which are synaptically driven
When is “the critical period” of brain development?
The timing of the critical periods varies depending on the brain function
