Aβ1-42 globulomer is a highly stable oligomeric Aβ complex, which mimics binding properties and pathology of other described oligomeric Aβ forms. For example, Aβ1-42 globulomer binds to primary hippocampal neurons and blocks long-term potentiation (LTP) in hippocampal slices. The pathological relevance of Aβ1-42 globulomer is supported by the observation that specific antibodies detect globulomer epitopes in brains of AD patients and Aβ-overproducing transgenic mice. These data suggest that a naturally occurring form of Aβ1-42 globulomer causes a defective information storage of hippocampal synapses and thus contributes to the cognitive deficits in brains of AD patients.