Adaptation in Helix pomatia neurons

1. Spike frequency adaptation has been studied on neurons of Helix pomatia subesophageal ganglia and interpreted by means of a behavioural model describing the phenomenon in neurons either silent or autorhythmic at rest. 2. At low stimulating currents the initial discharge frequency F(0) is linearly related to the current strength G. 3. In the linearity range F(0)/G each neuron was characterized by means of four model parameters: the proportionality constant between F(0) and G, the decay constant of the frequency, the inhibitory current from a single nerve impulse and the decay time constant of the inhibitory current. 4. The four parameters varied in different cells with a range of 0.18-4.98 Hz/nA, 1.02-3.85 sec, 0.05-0.95 nA and 1.74-22.33 sec, respectively. 5. Experimental results have been analyzed considering inhibitory current, electrogenic sodium pump and other proposed adaptation parameters.