However, MD doubled the fraction of inhibitory shaft synapse loss during the first 4 days of MD (repeated-measures analysis of variance [ANOVA] and Tukey’s post hoc test, p < 0.01). This increased loss persisted throughout the entire 8 days of MD. A decrease in inhibitory shaft synapse additions was also observed at 4–8 days MD (repeated-measures ANOVA and Tukey's post hoc test, p < 0.005). A larger than 3-fold increase in inhibitory spine synapse loss was observed during the early period of MD (repeated-measures ANOVA and Tukey's post

hoc test, p < 0.05). Analysis at intervals of 0–2 days MD and 2–4 days MD shows that the increase inhibitory spine synapse loss was specific to the first two days of MD selleck chemicals (Wilcoxon rank-sum test, p < 0.05; Figure 4D). Imaging over a 16 day period in control animals showed no fractional change in inhibitory synapse additions or eliminations across the imaging time course, indicating that the inhibitory synapse losses observed were specifically induced by MD (Figure S4C). These findings

demonstrate that inhibitory shaft and spine synapses are kinetically distinct populations and experience can differentially drive their elimination and formation. Long-term VX-770 supplier plasticity induced at one dendritic spine can coordinately alter the threshold for plasticity in nearby neighboring spines (Govindarajan et al., 2011 and Harvey and Svoboda, 2007). Electrophysiological studies suggest that plasticity of inhibitory and excitatory synapses may also be coordinated at the dendritic level. Calcium influx and activation of calcium-dependent signaling molecules that lead to long-term plasticity at excitatory synapses can also induce plasticity at neighboring inhibitory synapses (Lu et al., 2000 and Marsden et al., 2010). Conversely, inhibitory synapses can influence excitatory Sitaxentan synapse plasticity by suppressing calcium-dependent activity along the dendrite (Miles et al., 1996). Given the limited spatial extent of these signaling mechanisms (Harvey and Svoboda, 2007 and Harvey et al., 2008), we looked for evidence of local clustering between excitatory and inhibitory synaptic changes. We first looked at the distribution

of dynamic events resulting in persistent changes (both additions and eliminations) on each dendritic segment (68.1 ± 2.9 μm in length) as defined by the region from one branch point to the next or from branch tip to the nearest branch point. During normal visual experience, 58.2% ± 7.6% of dendritic segments per cell contained both a dynamic inhibitory (spine or shaft) synapse and a dynamic dendritic spine (Figure 5A). On these dendritic segments, a large fraction of dynamic inhibitory synapses and dendritic spines were found to be located within 10 μm of each other, suggesting that these changes were clustered (dynamic spines to nearby dynamic inhibitory synapses, repeated-measures ANOVA, p < 1 × 10−10; dynamic inhibitory synapses to nearby dynamic spines, repeated-measures ANOVA, p < 0.