Digital bridge for spinal cord allows paralyzed man to walk again; Warming in the arctic is disrupting the ground-squirrel\u2019s love life; Scientists completely map the activity of serotonin in the brain of a roundworm; Medium sized black hole in our galactic neighborhood could solve an astronomical puzzle; Plastic pollution and disease \u2014 \u2018Plasticosis\u2019 is a new plague for wildlife.