This Pilot Study seeks to develop further our in vitro model of neurotoxicity using a recently developed immortalised human embryonic stem cell line to create a rapid and high throughput in vitro biological assay that surpasses the inherent limitations of the currently accepted in vivo animal based assays. Animal use is significant for investigations into the nervous system. Indeed in 2009 procedures investigating the central nervous system accounted for the second largest number of animals used with 397,000 (11%) procedures carried out where mice, rats and fish were the most common species used (99% of this type of procedure). The long term aim of this project is to therefore replace/reduce the current in vivo methods of screening potential developmental/post-developmental neurotoxicants, thus significantly reducing the sacrifice of these animals for this purpose annually. In addition, this model will also greatly aid in the development of our other ongoing projects elucidating mechanisms of disease such as Alzheimer's development which are heavily reliant upon the use of transgenic animals. This has the potential to significantly reduce further the use of animals in brain research.