In June 2004, the results of an ambitious Antarctic ice-drilling project brought insight into hundreds of thousands of years of climatic changes. The extraordinary sample still has much to offer climate research — even as its successor is being drilled.

It has long been known that ice starts melting at temperatures far below its nominal freezing point, but why or how has remained enigmatic. An innovation in atomic force microscopy provides insights into how this process begins in the most abundant form of ice on Earth.

Myelin is a fatty substance that forms an insulating sheath around the axons of neurons. In mice, drugs of abuse induce neuronal-activity-regulated changes in the myelination of neurons in the brain’s reward circuitry that release the neurotransmitter chemical dopamine. This myelin plasticity is required for the learning of reward associations with drugs of abuse, such as morphine.