Thigmotaxis in young adult mice following nicotine administration. Nicotine (0.5 mg/kg) was administered for 5 consecutive days to a/a mice (a), and Avy/a mice (b). For graphical presentation, thigmotaxis was calculated as . Data are presented as mean ± SE; n = 5–8 per group. * p < 0.05 significantly different from saline-matched controls.