Conventional measures of intrinsic excitability are poor estimators of neuronal activity under realistic synaptic inputs
Fig 2
Firing responses of the hippocampal neurons indicate different degree of excitability under current step stimulation vs. simulated synaptic bombardment.
Voltage traces of a delayed firing type cell and the corresponding input-output relationship are shown under current step protocol in (A) and (B), respectively. (C) Firing response and (D) the spike count vs. AMPA-conductance relationship obtained from the same delayed type neuron under dynamic clamp protocol. Corresponding panels in (E-H) demonstrate the firing responses of a stuttering type cell under identical stimulus conditions. Note that the I-O relationships are very different between the two neuron types (B vs. F and D vs. H). (I) The threshold AMPA-conductance is plotted against the rheobase for all the recorded neurons (n = 380). (J) Total (cumulative) spike count from the dynamic clamp experiments is plotted against the total static spike count (n = 399). Colors indicate the three cell types.