RT Journal Article
SR Electronic
T1 Primed Facilitation of Homosynaptic Long-Term Depression and Depotentiation in Rat Hippocampus
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 887
OP 894
DO 10.1523/JNEUROSCI.18-03-00887.1998
VO 18
IS 3
A1 Lorne L. Holland
A1 John J. Wagner
YR 1998
UL http://www.jneurosci.org/content/18/3/887.abstract
AB Previous studies have demonstrated that prior synaptic activity can influence the subsequent induction of synaptic plasticity in the brain. Such temporal modulation of synaptic plasticity has been called “metaplasticity.” In this report, we describe the facilitatory effects of high-frequency stimulation on the induction of homosynaptic long-term depression (LTD) in the CA1 region of the rat hippocampus. The LTD induced by low-frequency stimulation (1 Hz) protocols was found to be homosynaptic and NMDA receptor-dependent. The facilitatory effects of the high-frequency stimulation-induced priming event itself were found to be NMDA receptor-independent and to have a duration of at least 90 min. The effects of priming also were heterosynaptic, because the induction of synaptic plasticity by low-frequency stimulation was enhanced at an unprimed synaptic pathway after the priming of an independent pathway. In addition to enhancing LTD, priming also enhanced the reversal of long-term potentiation elicited by a 5 Hz depotentiation protocol. Our results provide examples of how metaplasticity may play a key role in the ongoing modulation of the induction and stabilization of alterations in synaptic strength.