Figure 7.

Mean ± SEM for dendritic length (A) and number of branch endings (B) after either 4 weeks of repeated cocaine (15 mg/kg, i.p.) or saline injections (5 d/week, followed by a 4-week recovery period). Mean ± SEM for overall (C), thin (D), mushroom (E), and stubby (F) spine densities as a function of cocaine or saline injections. This regimen of chronic cocaine administration failed to produce any frank differences in any of the dendritic or spine morphologic indices examined in PL neurons. n = 4 saline injection; n = 7 cocaine injection, n = 6–8 neurons/rat.