  We theoretically investigate long-term potentiation (LTP) in the hippocampus
using a simple model of a neuron stimulated by three different time-structured
input signals (regular, Markov, and chaotic). The synaptic efficacy change is
described taking into account both N-methyl-D-aspartate (NMDA) and non-NMDA
receptors. The experimental results are successfully explained by our neuron
model, and the remarkable fact that the chaotic stimuli in the nonstationary
regime produce the largest LTP is discussed.
