A persistent change in neuronal activity after brief stimuli is a common feature of many neuronal microcircuits. This persistent activity can be sustained by ongoing reverberant network activity or by the intrinsic biophysical properties of individual cells. Here we demonstrate that rat and guinea pig cerebellar Purkinje cells in vivo show bistability of membrane potential and spike output on the time scale of seconds. The transition between membrane potential states can be bidirectionally triggered by the same brief current pulses. We also show that sensory activation of the climbing fiber input can switch Purkinje cells between the two states. The intrinsic nature of Purkinje cell bistability and its control by sensory input can be explained by a simple biophysical model. Purkinje cell bistability may have a key role in the short-term processing and storage of sensory information in the cerebellar cortex.
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We thank H. Meiri, E. Chorev and P. Mann-Metzer for excellent technical assistance, J.T. Davie for help with programming, and J.I. Simpson and T. Margrie for encouragement and helpful discussions. This work was supported by grants from the European Commission (M.H. and Y.Y.), Wellcome Trust (M.H and S.M), Gatsby Foundation (M.H), JSPS (K.K.), US-Israel BSF (Y.Y.), the Israel Science Foundation (Y.Y.), the Israel Science Foundation Center of Excellence 8006-00 (H.S.) and the Yeshaya Horowitz Association (Y.L.).