Recent work has described 3 forms of LTP that can be expressed at CA3-CA1 synapses in the hippocampus.
LTP 1 is short-lasting (time constant ~ 1 h in vitro) and depends on calcium release in dendritic spines via ryanodine receptors.
LTP 2 is of intermediate duration (time constant ~ 2 h in vitro) and requires calcium release in dendritic shafts via IP3 receptors.
LTP 3 is very stable (time constant > 4 h in vitro) and depends on somatic calcium influx via L-type voltage-dependent calcium channels.
At present, we are particularly interested in the mechanisms that link the different induction processes (ie, calcium influx via different routes) to the various maintenance processes underlying LTP 1, 2, and 3.
Possible projects for students
1) The relative roles of action potentials in the induction of LTP 1, 2, and 3
2) Behavioural testing for correlates of LTP 1, 2, and 3
3) Analysis of the specific molecular effector pathways underlying different forms of LTP
The main techniques used in the laboratory are whole-cell patch-clamp and field potential electrophysiology and 2-photon calcium imaging in hippocampal slices.