Analysis of these experiments was carried out manually using the Fitmaster software®. Frequencies of action potential firing are reported as the computed mean of the highest frequency observed in each neuron. Depolarizing spikes were considered as action potentials when they were short lasting (shorter than 10 ms at half amplitude) and when the amplitude reached 0 mV. Frequencies of action potentials were calculated as the number of action potentials divided by the current pulse time, also when only one spike was recorded. Rheobase was calculated as the mean of the minimal current injected to evoke an action potential.
