American Scientist

In this roundup, associate editor Katie L. Burke summarizes notable recent developments in scientific research, selected from reports compiled in the free electronic newsletter Sigma Xi SmartBrief. Online: https://www.smartbrief.com/sigmaxi/index.jsp

Humans Made Art Earlier

New dating of cave paintings in Indonesia reveals that they are more than 40,000 years old, casting doubt on theories of art in human prehistory. These paintings are among the earliest ever found, and their location is a surprise to archaeologists. Other contemporary cave art has been found only in Europe, and archaeologists thought that the practice of cave painting originated there. The revised age measurements, combined with previous findings that some carved patterns in Africa are 50,000 years old, suggest that humans may have developed artistic proclivities before their migration out of Africa, beginning around 75,000 years ago. Alternatively, artistic abilities may have arisen independently in different societies.

Aubert, M., et al. Pleistocene cave art from Sulawesi, Indonesia. Nature 514:223 (Published online October 8)

Stem Cell Therapies for Blindness

A new stem cell treatment for two types of macular degeneration shows promise in initial human trials. Researchers led by Robert Lanza of Advanced Cell Technology treated embryonic stem cells in the lab to induce their development into retinal cells and then injected them behind the affected retinas in 18 patients. After three years, more than half the test subjects experienced improved vision, and none experienced complications associated with immune system rejection of the new cells. In a separate study, researchers from University of Southampton discovered stem cells in the human eye that develop into light-sensitive cells. These cells hold promise for reversing some types of blindness, such as macular degeneration, through regenerative therapy. So far, the therapy has been researched only in the lab; clinical trials are expected to be under way in five years.

Chen, X., et al. Adult limbal neurosphere cells: A potential autologous cell resource for retinal cell generation. PLoS ONE doi:10.1371/journal.pone.0108418 (October 1)

Schwartz, S. D., et al. Human embryonic stem cell-derived retinal pigment epithelium in patients with age-related macular degeneration and Stargardt’s macular dystrophy: Follow-up of two open-label phase 1/2 studies. Lancet doi:10.1016/S0140-6736(14)61376-3 (Published online October 15)

Neural Tract Lost for 100 Years

A neural pathway was discovered but forgotten for more than 100 years, potentially because of a dispute between a student and his mentor. The vertical occipital fasciculus (VOF) connects parts of the brain important for perception. Jason Yeatman, now of University of Washington, re-discovered the structure a few years ago while working on his PhD at Stanford, but could not find mention of it in the scientific literature until a colleague alerted him to an 1881 brain atlas by German neurologist Carl Wernicke. The neurologist’s mentor was an anatomist named Theodor Meynert, who had proposed that all neural pathways connect front to back in the brain, an idea generally accepted among his contemporaries. But the VOF was a vertical connection, and it is mysteriously missing mention in Meynert’s publications following its discovery. Study of the VOF will help neuroscientists understand how the brain and vision system work together to perceive categories, such as reading words or recognizing a face.

Yeatman, J. D., et al. The vertical occipital fasciculus: A century of controversy resolved by in vivo measurements. Proceedings of the National Academy of Sciences of the U.S.A. doi:10.1073/pnas.1418503111 (Published online November 17)

Long-Armed Dinosaur Resolved

An incomplete fossil of a dinosaur with the longest forelimbs of any bipedal animal was first discovered in Mongolia in 1965. With arms longer than two meters, Deinocheirus mirificus was a puzzle to paleontologists, who were not sure where to put it on the dinosaur family tree. Two new, almost complete fossil skeletons of the creature have been unearthed in Mongolia in the past decade, resolving this half-century-long mystery. The fossils showed that this ancient beast is the largest known ornithomimosaur, a group of ostrichlike dinosaurs. Although these dinosaurs are known for being fast runners, the massive hindlimbs and heavy body of D. mirificus indicate that it was a slow mover. Stomach contents showed that it ate fish and was probably an omnivore that lived in a wet environment.

Lee, Y.-N., et al. Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificus. Nature 515:257 (November 13)

Odd Methane Source Feeds Fires

In a place called Yanartas, meaning “flaming stone,” in Turkey, there are fires that have been aflame for millennia. The source of the methane lighting the fires has been a mystery: It is not produced biologically, but abiotic reactions forming methane were thought to occur only at temperatures above those experienced at Yanartas. A new study by Giuseppe Etiope of the National Institute of Geophysics and Volcanology in Italy showed that a rare metal called ruthenium found in rock underneath the site can catalyze a reaction forming methane in the lab at temperatures below 100 degrees Celsius—within the range of the area’s climate.

Etiope, G., and A. Ionescu. Low-temperature catalytic CO₂ hydrogenation with geological quantities of ruthenium: A possible abiotic CH₄ source in chromitite-rich serpentinized rocks. Geofluids doi:10.1111/gfl.12106 (Published online September 18)