Genes that are switched on or off in the human brain differ between men and women. Moreover, these differences are not uniform. They vary across cortical regions and cell types. Scientists at the National Institute of Mental Health (NIMH) and the National Institute on Aging (NIA) used single-cell sequencing and unveiled distinct gene expression patterns regulated by hormones and sex chromosomes. This detailed map of the brain’s molecular biology shows how women and men switch on and off more than 3,000 brain genes differently and expands the catalogue of X chromosome genes that escape inactivation.

Antiretroviral therapies against HIV have been in use for more than 30 years and have enabled people living with HIV to maintain undetectable viral levels. Many of them are aging in good health. However, others present symptoms of cognitive decline. HIV can reach the brain and establish a reservoir there. Yet, it is still unknown what this reservoir is like, which cells are affected, and which comorbidities are typical of aging or are associated with the virus.

A collaboration of scientists from the NIH Brain Initiative consortium has published eight simultaneous studies in Neuron, Cell, Cell Genomics, Cell Reports and Cell Reports Methods, with the results of the Armamentarium project, a new set of gene therapy tools for the research and treatment of human brain disorders. The methodology, based on genetic techniques, RNA detection, genomic enhancers and viral vectors, is designed to access different CNS cell types, neuronal and non-neuronal cells, with common and reproducible protocols now available for any laboratory.

The way the brain ages is not the same in women and men. A study in mice has observed differences in the expression of the maternal and paternal X chromosomes that could explain variation in brain aging between the sexes and a faster deterioration in some women. Another study has discovered different survival strategies in the microglial cells of females and males. Both studies highlight sex differences that could have implications for several age-related neurological disorders, such as Alzheimer’s or Parkinson’s.

In the 1970s, scientists from several countries proposed to reconstruct, one by one, all the neurons in the brain as they appear under an electron microscope. They started with a small worm. Caenorhabditis elegans has only 302 neurons. It took 16 years. How much time would be required to repeat this arduous task for the 100 billion neurons in the human brain?

In the 1970s, scientists from several countries proposed to reconstruct, one by one, all the neurons in the brain as they appear under an electron microscope. They started with a small worm. Caenorhabditis elegans has only 302 neurons. It took 16 years. How much time would be required to repeat this arduous task for the 100 billion neurons in the human brain?

In the 1970s, scientists from several countries proposed to reconstruct, one by one, all the neurons in the brain as they appear under an electron microscope. They started with a small worm. Caenorhabditis elegans has only 302 neurons. It took 16 years. How much time would be required to repeat this arduous task for the 100 billion neurons in the human brain?

The map of the human brain is not a static image of the cellular architecture of the central nervous system (CNS). Throughout life, all living beings are born, develop and age. The brain of pregnant mothers reflects a dynamic that modifies this general picture. A collaboration of scientists from the University of California has studied the changes in the adult brain during pregnancy and observed that a large part of it adapts during the development of the fetus.

To understand the human brain, an international consortium of scientists has created the most complete atlas of this organ to date. The map reveals the anatomy, the architecture of the tissues, how or where each cell is, their function, gene expression and regulation. On Oct. 12, 2023, Science and Science Advances published a group of 21 studies that unveiled the map of the human brain, as well as the brains of nonhuman primates and mice, cell by cell, for an adult model and for the different stages of development.

While the liver is mostly known as the core of metabolism, contributing to the storage of nutrients and excretion of toxic substances, there is an increasing interest in how it interacts with the central nervous system through the liver-brain axis. At the 2023 European Association for the Study of the Liver (EASL) meeting in Vienna, Austria, group leader Kristina Schoonjans and her colleague Hadrien Demagny from the Laboratory of Metabolic Signaling at École Polytechnique Fédérale de Lausanne, Switzerland, gave talks setting out the context of inter-organ communication in liver disease, adding new findings from their research in the liver-brain axis.