Fig 1. In vitro TCR neuron response to injected frozen noise.

Left panel: Spike trains induced in a TCR cell by frozen noise with identical amplitude and various DC offsets; trace is a 3 s extract from a standard 300 s recording. Top: example trace at −50 mV. Bottom: example trace at −80 mV. Vertical bars in the panels in between mark the detected spikes in the 3 recorded replicates at 4 levels of depolarization, from top to bottom: −50, −60, −70 and −80 mV. The neuron responds earlier at more depolarized membrane potentials. Middle panel: 100 ms zoom of a single event starting at 1850 ms (zoom indicated in the left panel). Top and bottom show the event at −50 mV and −80 mV. Right panel: Cross-correllograms between a reference spike train at −80 mV and the spike trains obtained in the same cell at the different membrane states. Recordings from 5 cells (=15 traces), resulting in 10 comparisons at −80 mV, 15 comparisons at −70 and at −60 mV; only 2 cells gave sufficient results at −50 mV (6 comparisons). On depolarization the peaks shift to the left, indicating that the neurons fire earlier.