Just like hard drive sectors can fail, neurons can go bad as data processing, memory-storing units in your brain. In this video, a neuron lacks the protein needed to make connections with other cells, essentially becoming a bad sector.
While the neuron on the left looks undeniably sinister, those tendrils extending from it actually signal its healt—they are the neural connections vital to its data-transmitting task. The one on the right, however, fails to make the connections. Whether it's data stored in your dome or on your drive that you're concerned about losing—well, you're right to be. [MIT via io9]