Comparison of firing adaptation and afterpotential measured in vivo or in vitro.

A. AHPs recorded from a visual neuron in vivo: the square pulse evoked a smaller postpotential than sinusoidal current injection (4 mV and 49 s vs 6 mV and 54 s). B. Comparison between in vivo and in vitro conditions. Data are reported as mean ± SE. For sinusoidal current injection the values of adaptation index and postpotential was very similar in both conditions. In vitro conditions we observed a similar adaptation index from the same protocol but the postpotential was larger than in vivo condition.