Discoveries

What makes us human, and where does this mysterious property of “humanness” come from? President and Professor Rusty Gage, along with co-first author Carol Marchetto and colleagues, developed a strategy to more easily study the early development of human neurons compared with the neurons of nonhuman primates. The research offers scientists a novel tool to construct an evolutionary tree of multiple primate species to better understand the evolution of the human brain.

Scientists have long theorized that attention to a particular object can alter perception by amplifying specific neuronal activity and suppressing the activity of other neurons (brain “noise”). Professor John Reynolds, first author Anirvan Nandy and collaborators confirmed this theory by showing how too much background noise from neurons can interrupt focused attention and cause the brain to struggle to perceive objects. The findings could help improve designs for visual prosthetics.

Salk Professor Kuo-Fen Lee, first author Thomas Gould and collaborators found that a blood-clotting protein can unexpectedly degrade nerves—and discovered how nerve-supporting glial cells, including Schwann cells, provide protection from this degradation. The findings show that Schwann cells protect nerves by blocking the blood-clotting protein as well as other potentially destructive enzymes released by muscle cells. The work could have implications for diseases as diverse as amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer’s disease and schizophrenia.

Similar to the dozens of Sherpas who guide hikers up treacherous Himalayan mountains to reach a summit, the nervous system relies on elaborate timing and location of guidance cues for neuronal axons—threadlike projections—to successfully reach their destinations in the body. Professor Samuel Pfaff, first author Dario Bonanomi and collaborators discovered how neurons listen for directions and simultaneously filter out inappropriate instructions to navigate tricky cellular environments.