While scores of vision experiments are carried out on animals, often monkeys, that involve restraining their heads and implanting eye coils, such experiments are unjustifiable.

This week we report on a team of scientists who studied human volunteers to gain new insights into human eye movements that would not have been obtained through inapplicable and cruel animal experiments.

Other exciting breakthroughs in nonanimal research include a heart organoid that replicates many features of the developing heart and an entirely human study that charted detailed processes on how the human brain forms memories.

Tiny eye movements are under a surprising degree of cognitive control

Working with human volunteers and specialized sensitive equipment, researchers led by Weill Cornell Medicine, were able to discover how a very subtle eye movement known as ocular drift is controlled by cognitive processes and not simply responding to incoming signals from the retina.

Scientists led by Weill Cornell Medicine studied six human volunteers and recorded ocular drift, or tiny eye movements occurring even when the gaze appears fixed. During the process, the study participants were tasked with identifying letter pairs amongst a background of visual noise. 

They found that fine eye movements followed a pattern indicating that they were influenced by prior knowledge, suggesting a greater level of cognitive control over the eyes than previously expected. This knowledge could lead to better treatments for visual disorders that may have a motor component as well.

A miniature heart in a petri dish: Organoid emulates development of the human heart

Researchers at the Technical University of Munich (TUM) are the first to create an organoid of the heart with both cardiomyocytes, or heart muscle cells, and epicardium cells that line the outer layer of the heart.

They induced stem cells to develop into a miniature heart, or organoid, that can be used to study early heart development. Not only were they able to discover a new cell type from which the epicardium develops, they also confirmed that the organoid can be used in personalized medicine. Using cells donated from a patient with Noonan syndrome, which causes congenital heart defects, the researchers developed organoids that emulated the characteristics of the disease.

Researchers plan to utilize the organoids as a human relevant method to study treatments for heart disease, sparing animals from painful experiments.

This is your brain on everyday life

Researchers from Washington University in St. Louis and the University of California, Davis used human relevant technology to gain greater insight into the human brain and how it processes and forms memories.

Human volunteers watched short videos of everyday scenes and were then asked to recall what happened in the video, all while functional MRIs monitored their brain activity.

The researchers found that the temporal lobe, known to play a key role in memory, focused on the subject of the videos while the posterior medial network was more in tune with the environment. Signals from both brain areas go to the hippocampus which results in a cohesive scene.

While scientists continue to conduct many experiments on the brains of animals that are painful and invasive, there are many ethical, human studies that can provide more applicable knowledge about the human brain.