Columbia University (New York, USA) researchers have successfully generated functional neurons directly from human skin cells, including those taken from patients with Alzheimer's disease. Asa Abeliovich and colleagues started with known transcriptional regulators and, through a process of trial and error, identified a cocktail of factors that could turn human skin cells into neurons. While the process was not initially very efficient, they refined the protocol, ultimately converting about 50% of the cells. When studied in a dish, the neurons derived from healthy skin cells could fire and receive signals, just like normal neurons. Further, when placed into the brains of developing mice, the converted cells were able to connect up to the existing circuitry.  The method can also produce neurons from the skin cells of patients with a rare familial form of Alzheimer's disease (AD). The AD neurons superficially looked normal, but upon closer inspection, the researchers saw abnormalities in the processing of amyloid precursor protein, the source for the amyloid plaques that riddle the brains of those with Alzheimer's disease. The neurons also showed more general differences in the way proteins inside the cell move around.