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Natural patterns of activity and long-term synaptic plasticity
1University Department of Pharmacology, Oxford, OX1 3QT, UK. ole.paulsen@pharm.ox.ac.uk
Current Opinion in Neurobiology
|February 7, 2001
Summary
Synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), can be induced by pairing weak inputs with postsynaptic action potentials. The timing of these events dictates the type of plasticity, suggesting a Hebbian learning rule in pyramidal neurons.
Area of Science:
- Neuroscience
- Synaptic Plasticity
Background:
- Long-term potentiation (LTP) traditionally requires high-frequency inputs.
- Recent findings show LTP and long-term depression (LTD) can be induced by pairing weak inputs with postsynaptic activity.
- This challenges traditional views and offers new insights into in vivo synaptic modification.
Purpose of the Study:
- To investigate the conditions for synaptic modification in pyramidal neurons.
- To explore the role of temporal dynamics in inducing LTP and LTD.
- To understand the signaling mechanisms underlying synaptic plasticity in vivo.
Main Methods:
- In vitro experiments pairing weak synaptic inputs with postsynaptic action potentials.
- Analysis of the temporal order and window for synaptic modification.
- Investigation of backpropagating action potentials as global plasticity signals.
Main Results:
- Both LTP and LTD can be induced by precisely timed weak synaptic inputs and postsynaptic spikes.
- The temporal order of input and spike determines LTP or LTD, following a Hebbian rule.
- Backpropagating action potentials act as a global signal for plasticity, and postsynaptic bursting correlates with potentiation.
Conclusions:
- Synaptic modification in pyramidal neurons is sensitive to the precise timing of inputs and postsynaptic activity.
- Hebbian learning rules, incorporating temporal asymmetry, govern synaptic plasticity.
- Backpropagating action potentials and postsynaptic bursting are key mechanisms in vivo.