sentence: It stimulates integrin – substrate binding via syndecans ( Beauvais and Rapraeger , 2003 ) , and a range of PLL concentrations is used to obtain viable neurons in culture.We plated hippocampal neurons on glass coverslip dishes coated with PLL concentration of 0.01 , 0.05 , 0.5 , 1.0 , or 10 mg / ml and measured filopodial density and protrusion and retraction rates using the custom-written tracking method described in Figure 1 .