This web-like structure shows the abnormal accumulation of cholesterol in a mouse brain cell that contains an aberrant protein linked to Huntington's disease, a fatal condition marked by a progressive degeneration of brain nerve cells. While the gene underlying the disease has been identified, little is known about how it leads to such neuronal damage. But the discovery that cholesterol builds up in mouse brain cells expressing the Huntington's protein could offer new clues for understanding the mechanism of the disease in humans. Courtesy of Cynthia McMurray, a molecular biologist at the Mayo Clinic.