The expression mechanism of long-term potentiation (LTP) remains controversial. Here we combine electrophysiology and Ca(2+) imaging to examine the role of silent synapses in LTP expression. Induction of LTP fails to change p(r) at these synapses but instead mediates an unmasking process that is sensitive to the inhibition of postsynaptic membrane fusion. Once unmasked, however, further potenti...

read with interest the chapter, ‘‘ActivityDependent Central Sensitization and Synaptic Plasticity,’’ in the recent review article by Latrémolière and Woolf in The Journal of Pain. I noticed a number of issues in that chapter which deserve some discussion. These include the concept of synaptic longterm potentiation in pain pathways and its relation to the more general phrase ‘‘central sensitizat...

The formation of precise synaptic connections in the developing central nervous system involves activity-dependent control of synaptic strength. Correlated activity between the afferent input and postsynaptic neuron strengthens connections through long-term potentiation (LTP), while uncorrelated synaptic inputs are selectively diminished. In this issue of Neuron, Tao et al. report that LTP in y...

The hippocampal slice is a popular model system in which to study the cellular properties of long-term potentiation (LTP). Synaptogenesis induced by exposure to ice-cold artificial cerebrospinal fluid (ACSF), however, raises the concern that morphological correlates of LTP might be obscured, especially in mature slices. Here we demonstrate that preparation of mature hippocampal slices at room t...

Long-term potentiation (LTP) is a long-lasting strengthening of synaptic transmission that is triggered by brief periods of high-frequency synaptic stimulation. Other patterns of stimulation can produce a long-term weakening of synapses, a process termed long-term depression (LTD) or depotentiation. Synapses thus have a stable strength that can be bi-directionally modified in an activity-depend...

Repeated learning improves memory. Temporally distributed ("spaced") learning can be twice as efficient than massed learning. Importantly, learning success is a non-monotonic maximum function of the spacing interval between learning units. Further optimal spacing intervals seem to exist at different time scales from seconds to days. We briefly review the current state of knowledge about this "s...

We report here on specific ways in which synaptic long-term potentiation (LTP) affects the response selectivity of primary sensory cortical cells. LTP increases synaptic efficacy by incremental "steps," up to a "ceiling" at which additional bursts of afferent stimulation cause no further potentiation. Endogenous and exogenous agents have been shown to modulate these two paramenters of LTP, rais...

The protein synthesis-dependent form of hippocampal long-term potentiation (late-LTP) is thought to underlie memory. Its induction requires a distinct stimulation strength, and the common opinion is that only repeated tetani result in late-LTP whereas as single tetanus only reveals a transient early-LTP. Properties of LTP induction were compared to learning processes where repetition is often t...

Rapid place encoding by hippocampal neurons, as reflected by place-related firing, has been intensely studied, whereas the substrates that translate hippocampal place codes into behavior have received little attention. A key point relevant to this translation is that hippocampal organization is characterized by functional-anatomical gradients along the septotemporal axis: Whereas the ability of...

Restricted and regulated expression in mice of VP16-CREB, a constitutively active form of CREB, in hippocampal CA1 neurons lowers the threshold for eliciting a persistent late phase of long-term potentiation (L-LTP) in the Schaffer collateral pathway. This L-LTP has unusual properties in that its induction is not dependent on transcription. Pharmacological and two-pathway experiments suggest a ...