Research Article

Large and Small Dendritic Spines Serve Different Interacting Functions in Hippocampal Synaptic Plasticity and Homeostasis

Figure 2

Large and small dendritic spines in CA1 pyramidal cells respond to TEA with different time courses corresponding to different phases of the synaptic response. (a) Typical example of a small and a large spine imaged before (−10), during (0), and after washout (10–60 min) of TEA (25 mM, 5 min). Scale bar: 0.5 μm. (b) Quantification of changes in spine size relative to the pre-TEA measurement. Small spines, blue; large spines, red. Limits of the shading represent the mean change across time in the absence of TEA (time course control experiments). The dotted lines represent the mean change at each time point in response to sorbitol (osmolarity control experiments). Post hoc analysis of control data versus TEA (3-way interaction between size, time, and treatment): ; ; . (c) and (d) PPR recorded in the CA1 region of acute hippocampal slices in response to stimulation of the Schaffer collateral before, during, and after application of TEA (black symbols) or sorbitol (grey symbols) as above. Error bars: SEM. Grey shading: TEA perfusion. Inset: averages of fEPSPs recorded from a typical slice over 1 min at 10 s intervals at the time indicated (min). Scale bar: 1 mV, 10 ms.