(a) Representative photomicrographs of DIV 9 cortical neurons transfected with shCREB or a scrambled shRNA and then exposed to PCB 11 (1 pM) for 48 h. (b, c) The number of dendritic tips per neuron, presented as the % change from vehicle control, was quantified in cortical neurons exposed to vehicle (0.1% DMSO) or varying concentrations of PCB 11 (b) in the absence or presence of the CREB blocker, compound 666–15 (500 nM) or (c) following transfection with shCREB or a scrambled (control) shRNA. Data presented as the mean ± SD (n = 6 wells from 2 independent dissections). *Significantly different from vehicle control at p < 0.05, #Significantly different from corresponding PCB 11 concentration at p < 0.05 as determined using a nonparametric one-way ANOVA (p < 0.05) followed by Holm-Sidak’s multiple comparisons test