"Synaptic modification by STDP-like rules has been studied previously in ... navigation {27-29]..."

[27] Blum. K. I. et al. (1996)
"A model of spatial map formation in the hippocampus of the rat."
Neural Comp. 8, pp.85-93  => not-avalable => OK

[28] gerstner W. et al (1997)
Learning navigational maps through potentiation and modulation of hippocampal place cells.
J. computational Neurosci. 4, pp. 79-94 (1997) => done

[29] Mehta M. R. et al. (2000)
Experience dependent asymmetric shape of hippocampal receptive fiels 
Neuron 25, pp. 707-715. => done