An 11-residue fragment of the Aβ protein that retains the physical and biological characteristics of the full length peptide; decreases the viability of rat adrenal PC12 cells; decreases the viability of primary rat cortical neurons (1 nM to 30 μM); intracerebral injections in rats induces lesions of neuronal and tissue loss (20 nmol); induces learning and memory impairment in the Y-maze, novel object recognition, and contextual fear conditioning tests in rats when injected intracerebroventricularly