Long-term potentiation across rat cerebello-thalamic synapses in vitro

We previously demonstrated that rat cerebello-thalamic synapses undergo an ultrastructural change, consistent with expression of long-term potentiation, in association with motor adaptation. The aim of these experiments was to determine if long-term potentiation can be expressed at these synapses physiologically. Excitatory post-synaptic potentials evoked by electrical stimulation of cut cerebello-thalamic afferents were recorded intracellularly from thalamic neurons in 17-24 day old rat brain slice preparations. The experimental protocol involved long periods of low frequency single-shock control stimuli interrupted by brief high frequency trains of conditioning stimuli. Conditioning at 100 Hz evoked long-term potentiation in 5/6 cells and long-term depression in 1/6 cells. Conditioning at 200 Hz was unsuccessful in evoking long-term potentiation but did evoke long-term depression in 1/3 cells and no change in 2/3 cells. We conclude that long-term potentiation can be evoked across rat cerebello-thalamic synapses in vitro.