Functional plasticity in two afferent systems of the granule cells in the rat dentate area: Frequency-related changes, long-term potentiation and heterosynaptic depression

Krug, Manfred; Müller-Welde, Petra; Wagner, Maria; Ott, Tilman; Matthies, H

doi:10.1016/0006-8993(85)91242-9

Cited by 16 publications

(19 citation statements)

References 28 publications

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“…However, very few other studies of LTP persistence have been performed in other hippocampal or brain areas (21,22), and so it is not clear how ubiquitous these decay characteristics are. While there is growing neurobiological and network modeling interest in LTD as an equal partner to LTP in learning and information storage, there have been virtually no data describing its persistence over time in awake animals, apart from one study showing that it can last as long as a week (16).…”

Section: Discussionmentioning

confidence: 99%

“…Heterosynaptic LTD occurs readily in the dentate gyrus in acutely anesthetized preparations; for example, induction of LTP in the medial perforant path synapses on dentate granule cells is often accompanied by LTD of the nearby lateral perforant path synapses and vice versa (13,14). Heterosynaptic LTD of commissural and crossed perforant path responses has also been observed after perforant path stimulation (15,16). The case for LTD as a memory mechanism, however, is not as strong as that for LTP, in part because it is not known how readily it occurs in awake animals or how long it persists over days.…”

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confidence: 98%

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Immediate early gene expression associated with the persistence of heterosynaptic long-term depression in the hippocampus.

Abraham

Christie

Logan

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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Long-term depression (LTD) of synaptic efficacy is likely to be as important in memory processing as the more well-known long-term potentiation (LTP). The case for LTD serving as a memory mechanism, however, requires that it be shown to persist across days or weeks at least. Here we examined the persistence of heterosynaptic LTD in the medial and lateral perforant path inputs to the dentate gyrus in awake rats and correlated this persistence with the degree of immediate early gene expression as assessed immunohistochemically. Rats were chronically implanted with separate stimulatIng electrodes in the medial and lateral perforant paths and an extraceilular field potential recording electrode in the dentate hilus. After recovery from surgery, either the medial or the lateral perforant path was tezed with 400-Hz trains, and homosynaptic LTP and heterosynaptic LTD were followed across time. Heterosynaptic LTD was shown to occur readily in awake animals and to persist across days or weeks, depending on the simulation protocol. The persistence of LTD and LTP was highly correlated within animals. Additional animals, given the same tetanization protocols, showed that the greatest immediate early gene expression occurred following that protocol which consistently gave the longest-lasting LTP and LTD.These data support the proposed role of LTD in memory processing but question whether immediate early genes are important for the persistence of LTP, LTD, or both.Information storage in the central nervous system is widely believed to occur as a result of changes in the efficacy of synaptic connections between neurons. Early observations of synaptic plasticity were made in the hippocampus, where long-term potentiation (LTP) of synapses in the dentate gyrus was induced by brief high-frequency stimulation of perforant path afferents from the entorhinal cortex (1, 2). LTP can last for many weeks, depending on the initial stimulation conditions (3), and a major question of interest is how the biochemical changes associated with LTP are maintained over time in the face of molecular turnover. One possibility involves altered gene expression. Support for this idea comes from recent demonstrations that a variety of postsynaptic genes, including immediate early genes (IEGs), respond rapidly to LTP-inducing stimuli (4-7). IEGs are of particular interest because many code for putative transcription factors and thus may participate in the biochemical cascade leading to genomically driven, lasting adaptations by neurons to afferent activity. We have shown that zif/268 and krox2O, and to a lesser extent c-jun,junB,junD, andfos-related genes, are preferentially expressed by stimulation patterns that generate LTP lasting weeks (LTP3) as opposed to days (LTP2) (7-9).Information storage may also involve weakening of synaptic efficacy, and indeed there are now many examples in the literature of long-term depression (LTD) of synapses in the hippocampus and elsewhere (10-12). One common form of LTD is heterosynaptic LTD, which occurs at q...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 98%

Immediate early gene expression associated with the persistence of heterosynaptic long-term depression in the hippocampus.

Abraham

Christie

Logan

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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“…This depression is long-lasting and may persist for several hours to several days (Krug et al, 1985;Staubli and Lynch, 1990). Such decreases, collectively referred to as LTD, may occur in an input as a result of stimulation of a neighboring population of synapses (i.e., heterosynaptically) or in an input that receives the stimulation (i.e., homosynaptically).…”

Section: Long-term Depressionmentioning

confidence: 99%

Age-associated changes in Ca2+-dependent processes: Relation to hippocampal synaptic plasticity

1997

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“…Little interest was subsequently given to the phenomenon, as a number of labs were unable to replicate these results or to show that any depression that did appear persisted for any length of time (Schwartzkroin and Wester, 1975;Andersen et al, 1977;Alger et al, 1978;Andersen et al, 1980). Fortunately this technique lent itself readily to the induction of Address correspondence and reprint requests to Brian R. Christie (Levy and Steward, 1979;1983;Abraham and Goddard, 1983;Levy and Desmond, 1985;Krug et al, 1985), and interest in hippocampal LTD was not lost altogether. In 1989 LTD experienced a resurgence of interest when an activity-dependent, and hence associative, form of LTD was shown to accompany LTP in the CAI region in vitro (Stanton and Sejnowski, 1989).…”

Section: Long-term Depression (Ltd) In the Hippocampusmentioning

confidence: 94%

Long-term depression (LTD) in the hippocampus

Christie

1996

Hippocampus

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Functional plasticity in two afferent systems of the granule cells in the rat dentate area: Frequency-related changes, long-term potentiation and heterosynaptic depression

Cited by 16 publications

References 28 publications

Immediate early gene expression associated with the persistence of heterosynaptic long-term depression in the hippocampus.

Immediate early gene expression associated with the persistence of heterosynaptic long-term depression in the hippocampus.

Age-associated changes in Ca2+-dependent processes: Relation to hippocampal synaptic plasticity

Long-term depression (LTD) in the hippocampus

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