Methods and device to neutralize soluble toxic agents in the brain

Methods, agents and devices for treating a patient to reduce accumulation of certain proteins in the brain are described. Such proteins include A , and the methods, agents and devices are useful for reducing the accumulation of A , which is a principal constituent of the plaques associated with such diseases as Alzheimer's disease (AD). Antibodies to A , when delivered systemically or directly into the central nervous system, improve cognitive deficits in a transgenic mouse model of AD. However, unlike peripheral of antibodies to A , which increased cerebral vascular plaques and hemorrhages, direct central administration did not result in such an increase cerebral vascular plaques and hemorrhages.