Fig. 2. Characterizing the responses elicited by stimulation of either the parallel fibers (PF) or the afferent nerve (Aff). (A,B) Extracellular recording of the responses to Aff (A) and PF (B) stimulation. Each record represents the average response to eight consecutive stimuli delivered at a rate of 0.1 Hz and recorded at a depth of 500 µm below the surface of the DON. (A) The response of the DON to Aff nerve stimulation is characterized by an early positive component (arrowhead); the main triphasic component is marked by an upward arrow and the second small negative component is marked by a double arrowhead. (B) The response of the DON to PF stimulation is characterized by significant longer delay, the pronounced second negativity and the overall longer duration of the PF response in compare to Aff response. (C,D) Intracellular recording of the responses to Aff (C) and PF (D) stimulation. (C) Sub- and supra-threshold responses to Aff stimulation recorded intracellularly. The subthreshold synaptic potential was occasionally composed of two depolarizing phases separated by a short delay (arrow). (D) Sub- and supra-threshold responses to PF stimulation recorded intracellularly. Note the higher threshold of the PF evoked action potential.