Figure 2.

LMW AβOs, but not HMW AβOs, induce persistent cognitive impairment. A, HPLC size-exclusion chromatography revealed that oligomer preparations comprised two major peaks that were isolated and characterized by dot blot (left inset) and Western immunoblotting (right inset). High-molecular-weight AβOs are the major components in fraction 1, while low-molecular-weight oligomers constitute the majority of fraction 2. B–D, Mice received a single intracerebroventricular injection of 10 pmol of fractionated HMW AβOs, LMW AβOs or vehicle (VEH) and were tested in the object recognition task 24 h (B), 7 d (C), or 14 d (D) after injection. Error bars represent means ± SEM (n = 10 mice/group) of time spent on the novel (black bars) or familiar (white bars) objects. *p < 0.05 (statistically significant difference; one-sample Student's t test).