Spike timing dependent plasticity (STDP) requires the temporal
association of presynaptic and postsynaptic action potentials (APs).
However, some synapses in the CA1 region of the hippocampus are
suprisingle unreliable at signaling the arrival of single spikes to the postsynaptic
neuron [4]. In such unreliable synapses pairing of excitatory
postsynaptic potentials (EPSPs) and single APs at low frequencies is
ineffective at generating plasticity [2], [3]. A recent computational study
[7] has shown that the shape of the STDP curve strongly depends on
the burst interspike interval in the presence/absence of inhibition when a
presynaptic dendritic burst and a postsynaptic somatic spike were paired
together. In this study, we investigate via computer simulations the conditions
under which STDP is affected when now a high frequency somatic
burst instead of a single spike is paired with another dendritic spike. We
show that during such pairing conditions in the absence of inhibition a
symmetric STDP profile with a distinct positive LTP region is evident at
10-30ms interstimulus interval and flat LTD tails at all other interstimulus
intervals. The symmetry is preserved at all burst interspike intervals.
When inhibition is present, the STDP profile shape into a Mexican hat
shaped one or an inverted symmetrical one with flat LTP tails
