In a lab at the University of Pennsylvania, a plastic dish holds two rows of tiny black dots, pairs of them connected by dozens of thin, hairlike filaments. Each dot is a cluster of thousands of neurons, explains Douglas Smith, who is a professor of neurosurgery and the director of Penns Center for Brain Injury and Repair. The fibers that stretch between them actually comprise thousands of axons, long, slender projections that conduct electrical impulses away from each neurons central body. These bundles–each one a lab-engineered nerve–represent physical bridges that Smith hopes will help researchers like him mend previously irreparable injuries.

via Technology Review: Nervy Repair Job.