The week’s most astounding developments from the neobiological frontier.

December 14, 2023

New mouse brain atlas shows extraordinary diversity

The best, most comprehensive, and highly detailed map of a mammalian brain has dropped this week in an impressive set of nine papers from the BRAIN Initiative Cell Census Network (BICCN), a massive scientific collaboration funded by the U.S. National Institutes of Health. Profiling the spatial arrangements, functions, connectivity, gene expression, and neurotransmitter and neuropeptide activities in about 7 million separate brain cells, the new map is a benchmark reference atlas of the whole adult mouse brain. It “provides a tool for continued investigations into the development and evolution of the mammalian brain,” BICCN researchers write. Nature

Millions of cells in the mouse brain are grouped into 5,000 select cell types, shown here with saturated colored clusters. The animation shows how the various clusters on the left map onto slices from the mouse brain on the right, as indicated by colored dots on the tissue slice images. Courtesy Chen and Macosko labs

Computing with silicon chips and live brain organoids

At the end of a year that’s seen incredible advances (and drama) in artificial intelligence, it’s worth reflecting on how amazing is that very thing that inspired AIs in the first place: the human brain. Our brains are far more compact than AI servers and use a million times less energy to process, learn, and store the same information an artificial neural network would. Aiming to better mimic the brain’s structure and function for AI computation, researchers at Indiana University Bloomington have developed biological neural network hardware that marries traditional silicon chips with live brain organoids (think: Frankenstein’s brain in Robby the Robot’s body). Calling their construct “Brainoware,” it uses a high-density microelectrode array to send and receive information from live-cell organoids. While this is just a proof-of-principle, future more complex organoid neural networks “could inspire the development of more sophisticated and human-like AI systems,” the researchers write. Nature Electronics

How microbial diversity in your gut protects you from infection

On the heels of our story last week on disappearing microbes in the human gut, researchers at the University of Oxford have demonstrated the importance of gut microbiome diversity. In experiments with mice, they showed how different types of gut bacteria work together to protect us from harmful germs. Diverse communities of bacteria in the gut resist colonization attempts by pathogens by gobbling up the nutrients the invaders need to multiply and outcompeting them. Besides highlighting the importance of intestinal diversity, the work offers insight into the potential rational design of a future human gut by engineering our microbiomes to enhance our ability to fight off harmful germs. Science

What to expect when you’re expecting to vomit

Most women experience nausea during pregnancy, and perhaps as many as half suffer some vomiting. But up to 3 percent of women have pregnancies marked by severe sickness. They constantly feel nauseated and dizzy, puke often and uncontrollably, risk dehydration, and often lose weight. This condition is called hyperemesis gravidarum and its cause has been a long-standing mystery. According to researchers at the University of Cambridge, it’s actually a hormone called GDF15 produced by the fetus that’s the culprit. Hyperemesis gravidarum happens when a fetus produces too much GDF15 or when a woman has not had sufficient exposure to the hormone before her pregnancy. That suggests a tantalizing possibility: Could checking these levels pre-pregnancy identify women at risk? Would giving GDF15 ahead of their pregnancies to at-risk mothers help build their resistance? Could we someday see the end of morning sickness? Nature

All-day thermoregulatory clothing

Pity the poor naked mole rat, buried in its subterranean sub-Saharan Africa hidey-hole. Unlike humans and other mammals, it has no ability to thermoregulate and must spend its days in the almost constantly lukewarm confines of its burrow. Humans on the other hand roam freely, using our brain’s hypothalamus to control our internal body temperature regardless of changes to the ambient temp. But even we have our limits. Our natural comfort zone is 22° to 28°C (~71°–81°F). Now researchers at Nankai University in Tianjin, China, are suggesting a technological hack that could greatly expand this range. They designed clothing that uses organic photovoltaics to capture energy from the sun and convert it into thermal heat when it’s too cold or drive the absorption of body heat when it’s too hot. Wearing their light solar clothing could extend our comfort zone to 12.5°–37.6°C (~54°–100°F). Science

Company promises treatment to abolish allergies

In a series of experiments involving mice, macaques, and humans, researchers at Regeneron Pharmaceuticals in Tarrytown, New York, have designed a combination therapy they claim could “durably reverse allergies.” The therapy uses antibodies to target a molecule called IL-4Rα, which is essential for the human body’s production of the key allergy driver immunoglobulin E (IgE). Tamping down on IL-4Rα reduces IgE, but it does not completely eliminate it because of something known as “allergic memory.” Long-lived memory immune cells in the bloodstream can simply produce more IgE. So the researchers designed a second antibody that hangs a target on these long-lived cells, leading to their destruction. Together, this combination therapy completely prevented anaphylaxis in mice sensitized to have severe allergic reactions to dust mites, a common human allergen. Science Translational Medicine

Probing human T cells to enhance immunotherapy

Immunotherapies are transforming cancer care, and yet they only work in roughly 30 percent of people—and we can’t predict who will or will not benefit from this approach. Now scientists at the Gladstone–UCSF Institute of Genomic Immunology in San Francisco and at the Medical University of Vienna in Austria have used CRISPR to alter and probe the function of 385 human genes related to T cells, which are crucial for the modern class of cancer-killing medicines known as immunotherapies. The work pinpointed a number of specific, previously unknown amino acid changes in proteins like PIK3CD, VAV1, LCP2, PLCG1, and DGKZ that could boost or suppress the action of T cells by regulating their activation and function. The work shows how we could enhance immunotherapy in the future by genetically tuning a person’s T cells. Nature

Survival of the cutest

IWe should never underestimate the potential for something as simple as a cute animal emoji to spread appreciation for Earth’s diversity, say conservation biologists at the University of Milan, the University of Helsinki, and Grenoble Alpes University. Wanting to see how accurately we represent the phylogenetic tree of life through our selection of such icons, they produced a chart this week that shows the evolution of common plant and animal emojis on the site Emojipedia from 2015 to 2022. It shows a heavy human bias toward certain creatures. For instance, we humans love our animal emojis, but plants? Don’t bother. Among animals, we especially love vertebrates—cute and furry, of course. Insects and arthropods with those weird icky carapaces? Not so much! And microorganism emojis? They are barely there, and there are very few emoji representatives of the fungi kingdom even though they dominate life on Earth—everywhere except your phone, apparently. iScience

Detail of a phylogenetic tree of emojis available in 2019. iScience/Mammola et al