Synaptic plasticity in the subiculum (our first papers on subiculum, from a long time ago)

Proposed mechanism for the late phase of long-...
Proposed mechanism for the late phase of long-term potentiation, based on Lynch (PMID 14715912). (Photo credit: Wikipedia)

Take-home messages: The projection from hippocampal area CA1 to the subiculum sustains long-term potentiation in vivo [download the paper], and LTP reduces paired-pulse facilitation in this pathway [download the paper]. The subiculum continues to be underexplored relative to the rest of the hippocampal formation, despite its interesting connections with the anterior thalamus, among regions.

Neuroreport. 1998 Mar 30;9(5):847-50.

The projection from hippocampal area CA1 to the subiculum sustains long-term potentiation.

Commins S, Gigg J, Anderson M, O’Mara SM.

Long-term potentiation (LTP) is a popular model of the synaptic plasticity which may be engaged by the biological processes underlying learning and memory. Most available studies of LTP have concentrated on the analysis of LTP occurring in ‘early’ components of the hippocampal circuit (for example, dentate gyrus and area CA1). We examine here, for the first time, LTP as it occurs in the massive, unidirectional projection from CA1 to the subiculum in vivo. We show that this projection sustains high-frequency stimulus-induced LTP (10 trains of 20 stimuli at 200 Hz; intertrain interval 2 s; LTP 181 +/- 9% at 30 min post-LTP induction). In addition, input-output (I/O) curves show a leftward shift for all stimulation values. PMID: 9579677

Neuroreport. 1998 Dec 21;9(18):4109-13.

Interaction between paired-pulse facilitation and long-term potentiation in the projection from hippocampal area CA1 to the subiculum.

Commins S, Gigg J, Anderson M, O’Mara SM.

Studies of the interaction between long-term potentiation (LTP) and paired-pulse facilitation (PPF) may throw light on the role of presynaptic factors in LTP. We examine here, for the first time, the nature of PPF in the CA1-subiculum projection. PPF peaks at a 50 ms interstimulus interval (ISI) and is evident at ISIs from 10 to 500 ms. There is no PPF effect at a 1000 ms ISI. PPF decreases in magnitude post-LTP induction across the middle range of ISI values tested (30, 50 and 100 ms). There is a positive correlation between initial PPF values and LTP; this correlation increases as the ISI increases. Initial values and the change in PPF post-LTP are also negatively correlated.

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Author: Shane O'Mara

Neuroscientist