In reward-based learning, synaptic modifications depend on a brief stimulus and a temporally delayed reward, which poses the question of how synaptic activity patterns associate with a delayed reward. A theoretical solution to this so-called distal reward problem has been the notion of activity-generated "synaptic eligibility traces," silent and transient synaptic tags that can be converted int...

Regulation of brain-derived neurotrophic factor (BDNF) secretion plays a critical role in long-term potentiation (LTP). It is generally thought that the supply for this secretion is newly synthesized BDNF targeted to the synapse. Here we provide evidence that hippocampal neurons additionally recycle BDNF for activity-dependent secretion. Exogenously applied BDNF is internalized by cultured neur...

The impact of pentylenetetrazol-induced kindling on the effectiveness of theta pattern primed-bursts (PBs) for the induction of long-term potentiation (LTP) of field excitatory postsynaptic potentials (fEPSP) and population spikes (PS) were investigated in hippocampal CA1 of pentylenetetrazol-kindled rats in vivo. The results showed that shortly after kindling, control animals had normal LTP of...

It is widely believed that the brain processes information and stores memories by modifying and stabilizing synaptic connections between neurons. In experimental models of synaptic plasticity, such as long-term potentiation (LTP), the stabilization of changes in synaptic strength requires rapid de novo RNA and protein synthesis. Candidate genes, which could underlie activity-dependent plasticit...

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Using confocal microscopy in conjunction with microdrop application of Dil, we have imaged and measured individual dendritic spines of living hippocampal CA1 pyramidal neurons in acute brain slices, before and approximately 3 hr after induction of long-term potentiation by chemical means. Statistical analysis of changes in the length of individual spines, and comparison with results of Monte Ca...