Gangliosides are glycosphingolipids localized to the outer leaflet of the plasma 
membrane of vertebrate cells. The highest ganglioside concentration of any organ 
is found in the mammalian brain, where the gangliosides are enriched in the 
neuronal membrane, particularly in the synapses. There are four major brain 
gangliosides with the same neutral tetrasaccharide core to which one to three 
sialic acids are linked--the simplest being the GM1-ganglioside. These 
gangliosides have been shown to have neuritogenic and neuronotrophic activity 
and to facilitate repair of neuronal tissue after mechanical, biochemical or 
toxic injuries. Mixtures of native bovine brain gangliosides were adopted for 
pharmacological use in the treatment of peripheral nerve damage, and 
GM1-ganglioside has been applied for the treatment of CNS injuries and diseases. 
Beneficial effects of GM1 have been documented in the treatment of stroke and 
spinal cord injuries, particularly when the treatment has been initiated within 
a few hours of the acute event. Continuous intraventricular infusion of GM1 has 
recently been shown to have a significant beneficial effect in Alzheimer disease 
of early onset (AD Type I).