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. 2017 Sep 13;6:e26278. doi: 10.7554/eLife.26278

Figure 1. Theta frequency postsynaptic bursts of action potentials in CA1 neurons induce a long-term depression of excitatory synaptic transmission.

(A) Experimental paradigm. Hippocampal slice cultures were prepared from wild-type (WT) mice, transfected with ChR-mCherry and Cre-mCherry and treated with patterned photostimulation (PPS; 3 Hz; 50 ms blue light pulses; 1 or 24 hr). (B) Patterned postsynaptic burst firing of ChR2 transfected (blue trace) or untransfected neurons induced by photostimulation (blue bars). Scale bar = 100 ms/ 10 mV (right panel). (C1) Upper: Time course of brief PPS and recording. Simultaneous whole cell recordings from WT neurons transfected with ChR2-mCherry, Cre-mCherry, and MRE-GFP and neighboring untransfected neurons in cultures treated with brief PPS. Black fill triangles indicate the time window for recording. C2 Left: Group averages of evoked EPSCs (upper) and mEPSC frequency (lower) from transfected (red fill) and untransfected neurons (black fill). Error bars in this and all figures represent SEM. Inset: Representative evoked EPSCs (scale = 10 ms/20 pA) from transfected (red) and untransfected (black) neurons. Right: Evoked EPSC amplitudes (upper) or mEPSC frequency (lower) from individual cell pairs (open circles). Transfected cell is plotted as a function of untransfected cell. Mean value is plotted as average ±SEM (filled circle). Diagonal line represents equality. C3 Representative mEPSCs (scale = 500 ms/10 pA). (D1-3). The same as C, except cultures were treated with chronic PPS. N = 13–19 cell pairs/condition. Statistic: Paired t-test.

Figure 1.

Figure 1—figure supplement 1. Channelrhodopsin expression does not affect excitatory synaptic transmission.

Figure 1—figure supplement 1.

(A) Transfection of ChR2-mCherry into CA1 neurons of WT slice cultures, without photostimulation (PPS), does not affect excitatory synaptic transmission. Group data of evoked EPSC amplitudes and mEPSC frequency from dual whole cell voltage clamp recordings from untransfected CA1 neurons and neighboring neurons transfected with ChR2-mCherry in WT hippocampal slice cultures. n = 12 cell pairs/condition. Statistic: Paired t-test.