Closed-loop methodologies for cellular electrophysiology

While the design of closed-loop experimental protocols in cellular electrophysiology dates back more than 60 years, recent developments promise to significantly advance the field. We review a selection of recent applications of closed-loop methods in neurobiology, focussing on the intracellular and extracellular access to cellular excitability, employed to dissect the biophysical bases of information processing. We cover relevant methodologies targeting different levels of description, ranging from single ion channels to large ensembles of neurons, and extending across different time scales, ranging from milliseconds to longer intervals characteristic of the variability in the firing rate. We conclude by mentioning future perspectives and developments.