MODELLING THE STDP SYMMETRY-TO-ASYMMETRY TRANSITION IN THE PRESENCE OF GABAERGIC INHIBITION
Experimental studies have shown a symmetry-to-asymmetry transition of the spike-timing dependent plasticity (STDP) curve exists in the proximal stratum radiatum (SR) dendrite of the hippocampal CA1 pyramidal neuron, which is probably clue to the presence of GABAergic inhibition [2, 3, 4]. A recent computational model predicted that symmetry-to-asymmetry transition is strongly dependent on the frequency and conductance value of GABA inhibition and that the largest long term potentiation (LTP) value and the two distinct long-term depression (LTD) tails of the symmetrical STDP curve are centred at +10 ms, +40 ms and -10 ms, respectively [8, 9]. In the present paper, we continue to investigate even further via computer simulations the effects of gamma frequency inhibition and its conductance value to the symmetry-to-asymmetry transition of the STDP profile in the SR dendrite and predict that the transition is even more robust when there is a temporal offset between the onsets of the pre-post excitatory stimulation and the GABAergic inhibition. The largest LTP value and the two distinct LTD tails are inversely proportional to the increase of GABA conductance.
stdp gaba ca1 pyramidal neuron computer model ltp ltd hippocampus calcium