Successful CNS drug discovery requires a scalable, highly physiological neuronal model. Using directed differentiation of mouse embryonic stem (mES) cells, including mES cells isolated from a mouse model of Alzheimer's disease (AD), a highly homogeneous primary neuronal model amenable to phenotypic assays for production and synaptotoxicity of amyloid β-peptide was developed. This model furnishes a highly physiological and AD-relevant platform suitable for high throughput small molecule and functional genetic screens, providing specific small molecule compounds identified by such screens.