This month, we feature free and open-access studies from Current Biology, Neuron, Cell Reports, and Chem. The research explores topics including the significance of a sampling of the variola virus found in the mummy of 17th century child, how humans distinguish themselves within and navigate a social hierarchy, a cross-educational technique for performance gains in the hands, and the incredible speed of the light-capturing complex in cryptophyte algae.

Read on and enjoy!

Tracing the steps of smallpox in humans

Is our timeline of smallpox in human populations incorrect? When smallpox's causative virus—variola virus (VARV)—emerged and how it evolved to become so widespread across the globe have proven controversial, with claims of smallpox in Egypt, India, and China dating back millennia. Now a study published December 8 in Current Biology suggests that the evolution of smallpox is much more recent.

A Lithuanian mummy of a small child, dating from between 1643 and 1665, provides a sampling of VARV that causes smallpox that, when analyzed, possibly answers some questions surrounding the origins of smallpox in human populations and the evolutionary events of the disease over time. Hear more about this story on the Cell Press Podcast:

The disintegrated VARV sampling in the mummy's DNA was extracted and studied by Dr. Ana T. Duggan and colleagues at the McMaster Ancient DNA Centre at McMaster University, who found that it had the same gene degradation as that of 20th century VARV, indicating that gene function loss occurred before 1650. Surprisingly, the researchers concluded that these samples shared a common viral ancestor that originated sometime between 1588 and 1645.The samplings indicate an origin that coincides with a period of colonialization and exploration that could have contributed to the spread of smallpox around the world.

The researchers hope to use the samplings of the strains to further investigate when smallpox and other DNA viruses originated in humans.

Read more: 17th Century Variola Virus Reveals the Recent History of Smallpox

Ranking ourselves in the pecking order: Human social hierarchies and learning processes

Hierarchical business structures were first formally created in the early 20th century and often take the form of a "triangle." Within this model, someone at the narrow top of the structure is in charge. As the triangle widens, the order descends. But how good are we at figuring out our own place within the hierarchy?

In a study published in Neuron on December 7, scientists from DeepMind and University College of London present research on the mechanisms that underlie how humans learn and navigate structured forms of knowledge, such as social hierarchies. The study consisted of 30 healthy college-age participants who were asked to perform a task in an fMRI scanner. The task consisted of learning the power structures of companies and then analyzing the relative power of people at the company based on viewed interactions between different pairs of employees.

The study provides evidence that the prefrontal cortex, a part of the brain that covers the frontal lobe, plays a central role in how humans independently navigate social hierarchies and find their place within them, by successfully engaging with the hippocampus and amygdala. The researchers also provide evidence that individuals unconsciously participate in a ranking process, even when the task is not necessary. In other words, humans are able to independently piece together a picture of a social hierarchy and their place within it by estimating other individuals' power and then updating this information based on observations of different power dynamics. In this way, our brains automatically complete the puzzle of power dynamics that make up the hierarchy they are part of.

Dharshan Kumaran and colleagues hope their findings can be applied toward developing artificial general intelligence that can then be applied to solve some of the world's most challenging problems. A better understanding of human cognitive processing may prove valuable to creating and improving artificial intelligence and its applications, such as robots.

Read more: Computations Underlying Social Hierarchy Learning: Distinct Neural Mechanisms for Updating and Representing Self-Relevant Information

Tricking the brain

In a study published December 13 in Cell Reports, Drs. Ori Ossmy and Roy Mukamel at Tel-Aviv University show that one hand's work may improve performance in the other.

In the study, 53 participants were first tested for basic motor skills and then tested their gaming abilities by learning a video game using virtual reality technology. In the first of two experiments, each participant wore a 3D headset and engaged in cross-education, watching their left hand move on a screen while simultaneously completing a series of finger movements with the right hand. In the second experiment, the virtual left hand moved while the actual left hand was strapped into a motorized glove that matched the movements of the right hand.

The researchers found that after participants watched their left hands on screen, they were better able to actually use their left hand. The most noteworthy finding was that performance improved when the screen showed the gloved left hand that was matched with the movement of the right hand.

By effectively tricking the brain, the scientists showed that the left hand can learn even when it is not moving under voluntary control, and that healthy hands and limbs might be able to lead by example and help improve performance in damaged hands and limbs.The neuroscientific findings may be useful for new physical therapy models and therapy programs for patients who have lost strength in one of their hands.

Read More: Neural Network Underlying Intermanual Skill Transfer in Humans

The remarkable light-capturing ability of cryptophyte algae

Imagine a world much smaller and faster moving than ours, a world of tiny organisms where energy processing via sunlight happens in the blink of an eye. The under-the-surface activity of cryptophyte algae occurs within nanoseconds to make the most energy out of the small amounts of sunlight the algae captures in the sublayers of the ocean.

The findings appeared in a study published in Chem on December 8. The molecular structure of reaction centers in organisms that receive their energy from the sun varies among different species. The light-harvesting ability of chroomonas mesostigmatica, a cryptophyte algae that exists below the top layer of the ocean, is extremely efficient and fast due to its light-harvesting antennae structure, which makes it possible for the tiny organisms to retain and funnel as much light as possible.

The research team, led by Dr. Jacob C. Dean at the University of Princeton, studied extracted chromophores, the algae's sponge-like absorbing molecules, and tracked the processing of light to energy in the algae's harvesting structure. The chromophores were conditioned using short laser pulses to mimic the environment that the algae draws light from. The model allowed for the researchers to gain measurable results in the rate of energy processing between the chromosphores. As energy transferred, the chromosphores vibrated. The speed of vibration was more precise and speedy than in other organisms and allowed for efficient energy processing that was incomparable to its neighboring ocean organism partners.

The results may help developers in the field of solar technology if they are able to learn to mimic the efficiency and speed of the energy transfer that the algae's harvesting complex performs.

Read More: Vibronic Enhancement of Algae Light Harvesting