Rebuilding Neurons of the Central Nervous System After Injury
Damage to the central nervous system — the brain and spinal cord — tends to be permanent. Some evidence shows axons can be encouraged to regrow, but it's unclear whether these approaches also support remyelination of nerve fibers or re-establish the clusters of ion channels needed for signal conduction. In this study, researchers find deleting the tumor suppressor gene PTEN and stimulating an immune response dramatically enhanced axon growth, remyelination, and ion channel clustering. The results are the first to demonstrate that regenerated nerves in the central nervous system can restore myelin and ion channel clustering necessary for normal signaling.
Corresponding author: Matthew Rasband, [email protected]
Enriched Environment Prevents Neuroinflammatory Response to Alzheimer's Protein in Mice
Alzheimer's disease produces an inflammatory response by the brain's innate immune cells, microglia, which is thought to exacerbate the disease. Environmental enrichment appears to reduce the risk of developing Alzheimer's disease, but we don't know whether it reduces neuroinflammation. In this study, researchers find that mice housed in enriched environments have more microglia in the memory centers of their brains than those raised in standard cages, and they are protected against the harmful inflammatory effects typically seen after injection of the misfolded Alzheimer's protein amyloid-β.
Corresponding author: Dennis J. Selkoe, [email protected]
Epigenetic Changes Reprogram Schwann Cells to Repair Injured Nerves
Schwann cells are the myelin-producing cells for the peripheral nervous system, the nerves outside of the brain and spinal cord. After a peripheral nerve injury, Schwann cells alter gene expression to help maintain and regrow neurons. In a new study, researchers reveal the epigenetic changes that activate Schwann cells' "repair" genes and promote neuron survival and regeneration. Therapies that promote the repair genes could improve recovery from nerve injury, which becomes less efficient with aging.
Corresponding author: John Svaren, [email protected]
Activating Enzyme in Mice Enhances Myelination, Speeds Up Signaling, and Improves Memory
Myelin insulates nerves and speeds up the transmission of electrical signals. In adults, a small population of precursor cells produce new myelin, but there is great interest in finding ways to prod mature cells to make new myelin in diseases where it is destroyed, such as multiple sclerosis. In this study, researchers find that sustained activation of an enzyme important for myelin production drives mature cells to produce myelin, leading to increased myelin thickness, faster electrical signaling, and improved learning in mice.
Corresponding author: Sharyl Fyffe-Maricich, [email protected]
Enhancing Effects of Neurotransmitter GABA in Cerebellum Reduces Alcohol Consumption in Mice
Genetics play a large role in alcohol use disorders, and studies suggest some of the genes involved affect an area of the brain called the cerebellum. In a new study in mice, researchers find genetic differences in how the cerebellum responds to alcohol: Alcohol enhances inhibitory signaling in the cerebellum in a strain of mice with characteristically low alcohol tolerance, but suppresses this signaling in a strain of mice with higher tolerance and a preference for alcohol. This strain of mice consumes large amounts of alcohol, but after being injected with a compound to enhance inhibitory signaling in the cerebellum, they consumed less alcohol, suggesting that drugs targeting inhibitory signaling in the cerebellum could help curb excessive alcohol consumption in people.
Corresponding author: David Rossi, [email protected]
Perception of Punishment Alters Compliance With Norms
Does the threat of punishment make people more or less likely to comply with societal norms? It may depend on how the punishment is perceived. In this study, researchers asked participants to allocate a portion of money to a partner. Allocating too little could result in a penalty. Before making their decisions, participants were told whether the penalty would be enforced as well as who would enforce it — a computer or the partner. Participants gave more money to the partner when the partner lifted the penalty and less money when they enforced the penalty. When the computer decided, enforcement played no role in giving. Additional studies using fMRI and brain stimulation revealed the brain areas involved in punishment perception.
Corresponding author: Xiaolin Zhou, [email protected]
The Journal of Neuroscience is published by the Society for Neuroscience, an organization of nearly 38,000 basic scientists and clinicians who study the brain and nervous system.
Check out these newsworthy studies from the Aug. 31, 2016, issue of JNeurosci. Media interested in obtaining the full text of the studies should contact [email protected]