Alzheimer’s disease (AD) represents the most common cause of dementia. Even if AD is commonly viewed as a disorder primarily of memory, there are several other additional domains, including visual function. Accumulating evidence suggests that the magnocellular or M-pathway subsystem of visual pathways is preferentially affected in AD compared to other neurodegenerative disease. A study of Sartucci et al. few years ago tested the three main visual pathways subsystem electrophysiologically in AD patients. They used Pattern Electroretinograms (PERG) and Visual Evoked Potentials (VEP) to luminance-contrast and chromaticcontrast stimuli to elicit responses differentially driven by generators of M-pathway, P-pathway (Parvovellular) and K-pathway (Koniocellular), and found that responses driven by the M-pathway were relatively more altered. The results of Sartucci et al., together with the body of available literature, are consistent with the hypothesis that a primary dysfunction of M-pathway impairment does occur in a sufficient number of AD patients to warrant support for a specific Magnocellular deficit associated with this disease.
Magnocellular stream, Alzheimer’s disease, Visual pathways subsystem, Chromatic and luminance visual evoked responses