Fig. 5.

Stimulation of single interneurons causes Purkinje cells to switch between states in paired interneuron to Purkinje cell recordings. (A) Example traces from one pair in which the Purkinje cell was either in a down state (Upper traces) or an up state (Lower traces) at the time that the presynaptic interneuron was stimulated (10 action potentials at 50 Hz). Action potentials are truncated to show membrane potential. Inset shows the IPSC that was recorded in the Purkinje cell in voltage clamp, whereas the presynaptic interneuron fired one action potential in current clamp (holding potential, −74 mV). (B) Raster plot of action potentials of all traces from the cell in A. (C) The average probability across all cells (n = 6) of a state change occurring at the time of stimulation in both the stimulated sweeps and interleaved control sweeps in which no stimulation was applied. MLI, molecular-layer interneurons.