Neurodegenerative diseases selectively target subpopulations of neurons, leading to the progressive failure of specific neuronal systems. The basis of such selective neuronal vulnerability has largely remained elusive. The factors that determine selective vulnerability in neurodegeneration are poorly understood conditions in vitro and in vivo. As a consequence, investigating these factors requires experimental approaches for monitoring the disease process in defined subtypes of neurons. The micropatterned substrates are well-suited for analyzing individual neurons within a culture as they separate cells based on their patterned spatial arrangement. We cultured iPSC-derived neurons on substrates with a line-shaped micropattern and immunolabeled them with an antibody against TH at day 70 of differentiation (Figure 2E). We were able to easily distinguish between TH-positive (arrows with open arrowhead) as well as TH-negative (arrows with closed arrowhead) neurons appearing in each of the parallel lines. Such experimental conditions allow examination of disease-associated processes in the more vulnerable dopaminergic neurons in comparison to the less vulnerable non-dopaminergic neurons. We next demonstrate that functional studies such as axonal transport of mitochondria and neurite outgrowth can be performed in these
