Research Article

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

Figure 3

Synapses in DG granule cells behave differently from CA1 synapses in response to the same TEA stimulus. (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. 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). Post hoc analysis of control data versus TEA (3-way interaction between size, time, and treatment): ; ; ; . ((c), (d)) Slope and PPR of fEPSP recorded in the DG granule cells region in organotypic and acute hippocampal slices in response to stimulation of the perforant path, before and after application of TEA (black), as above, and high osmolarity ACSF (grey), as above. Closed symbols represent points where responses were too small for reliable measurement. Grey shading: TEA perfusion. Error bars: SEM. 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.