Arf4 Regulates Dendritic Spine Development Figure 5. Decreased dendritic spine density and mEPSC amplitude in the DG of Arf4+/2 mice compared to WT mice. (A) Representative dendrites for DG granule cells of WT and Arf4+/2 mice at 4 months of age (n = 4 mice/genotype). (B) Averaged total spine density per mm dendrite length in the dentate gyrus of WT and Arf4+/2 mice (28–30 neurons/genotype). (C) Spine densities for specific spine subtypes in the DG of WT and Arf4+/2 mice. (D–F) Electrophysiological recordings reveal a decrease in amplitude of mEPSCs in Arf4+/2 (n = 9 cells) compared to WT controls (n = 6 cells) at 2 months of age. All data are mean6SEM. * p,0.05, ** p,0.01, *** p,0.001. (G–H) Spontaneous mEPSC frequency is not altered in Arf4+/2 granule cells (n = 9 cells) compared to WT granule cells (n = 6 cells) at 2 months of age. doi:10.1371/journal.pone.0046340.g005 were digitized at 20 kHz by a Multiclamp 700A amplifier (Axon Instruments, Union City, CA) and acquired with a Digidata- 1322A digitizer and WinLTP program (WinLTP Inc, University of Bristol, UK). Offline analysis was performed using Mini-analysis program (Synaptosoft inc) and the threshold setting for event detection was set at 4x the amplitude of baseline noise. Four PLOS ONE | www.plosone.org 6 September 2012 | Volume 7 | Issue 9 | e46340