QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

Help viewing high resolution images Return to article

Fig. 3. Repetitive sub-threshold Schaffer-collateral stimulation (100 microseconds, 1 Hz) revealed postsynaptic depolarisations of unequally distributed amplitudes in GluR-type glial cells. Extracellular field potentials and membrane potentials of a GluR cell were simultaneously recorded in a p11 mouse (V_rest=–80 mV, R_i=400 M, C_m=30 pF). (A) Typical pairs of recording traces are given. Single stimulation pulses caused stable dendritic field potentials (A_1,2 upper traces, C upper trace) and time-correlated glial depolarizations of up to 7.3 mV (A₁, lower trace) or glial failures (A₂, lower trace). Spontaneous glial depolarisations were observed in a few cases (A₃ arrow, 0.9 mV). (B) The average of 119 successively recorded pairs of traces is depicted with different time scaling. (B₁) Field potentials showed only synaptic potentials (449±65 µV) without postsynaptic population spikes, as visualized at higher time resolution. (B₂) The corresponding glial ePSPs averaged out at 2.4±1.8 mV. (C) The time course of field potential amplitudes (crosses, upper trace) and GluR cell ePSPs is plotted. While field potentials remained almost unchanged, the glial responses represented a mixture of failures and depolarisations over the 2 minutes recording period (circles, lower panel). (D) The amplitudes of the glial ePSPs were clearly non-Gaussian distributed (D₁). The noise amplitude histogram was received from analysing baseline recorded at resting potential (1 second, corresponding to 3106 points) and fitting to a Gaussian function (D₂). The Gaussian fit displayed a half width of 124±5 µV and peaked at –80.7±0.09 mV. For clarity, the centre was scaled to 0 mV. All data in this figure were obtained from the same GluR cell, [Cl^–]_i was always 135 mM.

Return to article