Exclusion criteria.
Cells were excluded from experiments when i) their resting membrane potential (Vrest) was above -50 mV, ii) the membrane resistance was higher than 1000 MΩ, and iii) no AP could be elicited in the no light condition. Traces were excluded from the analysis when: i) the starting Vm (calculated in the 100 ms preceding the depolarizing current step) in the no light condition differed by more than 5 mV from the starting Vm in the light condition, ii) there was an instability in membrane potential, and iii) a degradation of neuronal whole-cell recording (depolarization of resting potential > 10 mV, AP overshot below 0mV, or access resistance > 60 mΩ 11Revised from initial proposal of access resistance > 40 mΩ, after editorial approval on 13 Sept 2021. Analysis using 40 mΩ criteria lead to qualitatively similar results that are available at https://osf.io/amvkq).
Competing Interests: the authors declare no competing financial interests.