Effect of berberine chloride on the impairment of spatial memory induced by Aβ(1–40) injection. (A) Escape latencies per group of four trials tested in a morris water maze over 7 days. (B) The number of crossings over a position where a platform had been was measured for 120 s at seventh days after the last acquisition test. Values represent the means ± SD of 6 rats. * P < 0.01 when compared with the normal group. # P < 0.01 when compared with the Aβ(1–40) injection group.