Long-term potentiation at the apical and basal dendritic synapses of XXXX after local stimulation in behaving @entity35 .

@entity308 @entity1249 @entity195 @entity655 @entity35 @entity116
1. We recorded the extracellular excitatory postsynaptic potentials (EPSPs) in @entity1249 in the freely behaving @entity35 after stimulation of the apical dendritic and basal dendritic afferents. The apical dendritic population EPSP was negative at the apical @entity655 and positive at stratum oriens and alveus. The basal dendritic population EPSP was negative at basal dendritic layer (stratum oriens) and positive at the cell body and apical @entity655 . We delivered various tetanic stimulus patterns in an attempt to elicit long-term potentiation (LTP) at the apical dendritic synapse of @entity1249 pyramidal cells. A 200-Hz high-frequency train (HF) 1 s in duration was more successful than theta-frequency primed bursts (PBs; 1 or 4 priming pulses followed by 10 or 4 pulses at 100 Hz) in eliciting LTP of the apical dendritic population EPSP, recorded either ipsilaterally or contralaterally. 3. @entity116 applied to the apical dendritic afferents occasionally elicited long-term @entity308 (LTD) at an intensity lower than the LTP threshold. LTD persisted to > or = 1 day after a @entity116 . 4. High-intensity tetanic stimulations often elicited hippocampal afterdischarges (ADs). If the @entity195 duration was brief (< 15 s), apical dendritic LTP could follow the @entity195 . However, if the @entity195 duration was long, no apical dendritic LTP was observed. @entity116 that evoked an apical dendritic LTP typically evoked a short hippocampal @entity195 < 15 s in duration. 5. LTP of the basal dendritic population EPSP was readily elicited either after an HF or a PB @entity116 of low (1.5-2 times threshold) stimulus intensity.(ABSTRACT TRUNCATED AT 250 WORDS)
