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. Author manuscript; available in PMC: 2014 Oct 30.
Published in final edited form as: Neuron. 2013 Oct 30;80(3):10.1016/j.neuron.2013.09.044. doi: 10.1016/j.neuron.2013.09.044

Figure 4. Presynaptic homeostasis is achieved by parallel changes in the size of the readily releasable vesicle pool and presynaptic calcium influx.

Figure 4

A–B) Variance-mean analysis supports a RIM-dependent modulation of the RRP during synaptic homeostasis. Left, example EPSC traces for a WT NMJ at the indicated extracellular calcium concentration (millimolar). B) Example EPSC amplitude variance-mean plots of two WT synapses in the absence (gray) and presence (black) of PhTX with parabola fits (solid lines) that were extrapolated to the x-intercept (dashed lines; see Muller et al., 2012). C) Representative traces for measurement of the spatially averaged calcium signal within synaptic boutons at the NMJ in a wild type (control) and GluRIIA mutant. The homeostatic enhancement of presynaptic release is correlated with a statistically significant increase in the peak amplitude of the spatially averaged calcium signal (see Muller and Davis, 2011).