Theta-Burst Stimulation Induces Long-Term Potentiation During Beta Oscillation, but Not During Epileptic Discharges, in Rat Hippocampal Slices
Rats exhibit several physiological rhythms—θ, β, and γ rhythms, sharp waves, and ripples—that are related to memory processing. They also exhibit pathological epileptic discharges, and these discharges suppress memory processes. What is the difference between rhythms and discharges? The θ, β, and γ rhythms are reproduced in hippocampal slices. Long-term potentiation (LTP) was easily induced during the generation of carbachol-induced β oscillations, whereas it was suppressed during the generation of gabazine-induced epileptic discharges. These results suggest there is a difference in the mechanism of LTP induction between physiological β oscillations and the pathological rhythm of epileptic discharges. Synaptic plasticity is necessary for induction of the rhythm. It is therefore suggested that synaptic plasticity is not supported during epileptic discharges whereas it can be occurred during the physiological rhythm. This difference could differentiate the memory processes of the two rhythms in vivo.
KeywordsSynaptic Plasticity Memory Process Hippocampal Slice Sharp Wave Schaffer Collateral
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