To the Editor.
—The article by Dr Stern and colleagues1 reports an important relationship between risk for AD and education, a relationship that came under scrutiny following the report of Zhang et al.2 Subsequent reports have suggested a protective role of education, possibly through increased neuronal synapse density.3For several decades, computational neuroscientists, cognitive psychologists, and computer scientists have incorporated anatomical and physiological data into neural network computer simulations to replicate4 and, more recently, to study5,6 brain function.In general, neural network development can be separated into three phases (design, training, and testing) with simple models usually constructed with at least three layers: input (I), hidden units (HUs), and output (0). The I layer is equivalent to a sensory system such as vision, while HUs correlate with association cortices. Hidden units are sandwiched between the I and O layers with the I output serving as the
Powell AL, Brooks J, Zahner DA, Zhang ZM, Akay YM, Micheli-Tzanakou E. Education, Occupation, and Alzheimer's Disease. JAMA. 1994;272(18):1405-1406. doi:10.1001/jama.1994.03520180029017