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During fetal development of the mammalian brain, the cerebral cortex undergoes a marked expansion in surface area in some species, which is accommodated by folding of the tissue in species with most expanded neuron numbers and surface area. Researchers have now identified a key regulator of this crucial process.

Different regions of the mammalian brain are devoted to the performance of specific tasks. This in turn imposes particular demands on their development and structural organization. In the vertebrate forebrain, for instance, the cerebral cortex – which is responsible for cognitive functions – is remarkably expanded and extensively folded exclusively in mammalian species. The greater the degree of folding and the more furrows present, the larger is the surface area available for reception and processing of neural information. In humans, the exterior of the developing brain remains smooth until about the sixth month of gestation. Only then do superficial folds begin to appear and ultimately dominate the entire brain in humans. Conversely mice, for example, have a much smaller and smooth cerebral cortex.

“The mechanisms that control the expansion and folding of the brain during fetal development have so far been mysterious,” says Professor Magdalena Götz, a professor at the Institute of Physiology at LMU and Director of the Institute for Stem Cell Research at the Helmholtz Center Munich. Götz and her team have now pinpointed a major player involved in the molecular process that drives cortical expansion in the mouse. They were able to show that a novel nuclear protein called Trnp1 triggers the enormous increase in the numbers of nerve cells which forces the cortex to undergo a complex series of folds. Indeed, although the normal mouse brain has a smooth appearance, dynamic regulation of Trnp1 results in activating all necessary processes for the formation of a much enlarged and folded cerebral cortex.

As outlined in a study published in Developmental Cell, researchers have discovered a novel function for p27 in the control of interneuron migration in the developing cerebral cortex.

The cerebral cortex is one of the most intricate regions of the brain whose formation requires the migration and integration of two classes of neurons: the projection neurons and the interneurons. These neurons are born in different places and use distinct migration modes to reach the cortex. While several signaling pathways involving various molecules have already been associated with projection neuron migration, the molecular mechanisms that control interneurons migration remain elusive.

In this study, researchers unveiled a novel activity of p27—a protein initially described for its activity as cell cycle regulator—in dynamic remodelling of the cell skeleton. This skeleton, named cytoskeleton, underlies tangential migration of interneurons in the cerebral cortex. Juliette Godin, primary researcher states: At the molecular level, p27 acts on two cytoskeletal components, the actin and the microtubules. It promotes nucleokinesis and branching of the growth cone through regulation of actine. In addition, it promotes microtubule polymerisation in extending neurites. Both activities are required for proper tangential migration of interneurons in the cortex.

To an untrained observer, the electrical storm that takes place over the brain’s neural network seems a chaotic flurry of activity. But as neuroscientists understand it, the millions of neurons are actually engaged in a sort of tightly choreographed dance, a tango of excitatory and inhibitory neurons. How is this precise balance that makes normal function possible achieved during development? And how does it go wrong in diseases like epilepsy when brain activity goes out of control?

Focusing on the cerebral cortex, the part of the brain controlling thought, sensory awareness, and motor function, a group of Harvard Stem Cell Institute (HSCI) researchers in the Department of Stem Cell and Regenerative Biology (SCRB), led by Assistant Professor Paola Arlotta, has discovered that excitatory neurons control the positioning of inhibitory neurons in a process that is critically important for generating balanced circuitry and proper cortical response.

Professor Takao Hensch, a collaborator on the study in the Harvard Center for Brain Science, Department of Molecular & Cellular Biology (MCB), had previously shown that the maturation of this circuit balance triggers critical periods of brain development. Certain inhibitory cells appear particularly vulnerable to genetic or environmental factors in early life, contributing to mental illness, such as schizophrenia or autism spectrum disorders.

The cerebral cortex, which controls higher processes such as perception, thought and cognition, is the most complex structure in the mammalian central nervous system. Although much is known about the intricate structure of this brain region, the processes governing its formation remain uncertain. Research led by Carina Hanashima from the RIKEN Center for Developmental Biology has now uncovered how feedback between cells, as well as molecular factors, helps shape cortical development during mouse embryogenesis.

The cortex is made up of layers of interconnecting cells that are produced in a particular order from progenitor cells. The relatively cell-sparse outer layer is formed first, then the dense deep layer, and finally the tightly packed upper layer. Hanashima and her colleagues were interested to discover exactly how the various layers form, so they created a mouse model that enabled them to control the expression of a particular protein, Foxg1, known to be involved in cortical development.

The Foxg1 gene, if switched on toward the end of embryogenesis after the outer layer of neurons has formed, triggers the production of deep-layer neurons, followed by upper-layer neurons (Fig. 1). The researchers found that it does this by repressing the activity of another gene, called Tbr1, in the outer-layer neurons.

A team of researchers from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and Stony Brook University have devised a new quantum algorithm to compute the lowest energies of molecules at specific configurations during chemical reactions, including when their chemical bonds are broken. As described in Physical Review Research, compared to similar existing algorithms, including the team’s previous method, the new algorithm will significantly improve scientists’ ability to accurately and reliably calculate the potential energy surface in reacting molecules.

For this work, Deyu Lu, a Center for Functional Nanomaterials (CFN) physicist at Brookhaven Lab, worked with Tzu-Chieh Wei, an associate professor specializing in quantum information science at the C.N. Yang Institute for Theoretical Physics at Stony Brook University, Qin Wu, a theorist at CFN, and Hongye Yu, a Ph.D. student at Stony Brook.

“Understanding the quantum mechanics of a molecule, how it behaves at an atomic level, can provide key insight into its chemical properties, like its stability and reactivity,” said Lu.

On this explainer, Neil deGrasse Tyson and comic co-host Chuck Nice break down Big Bang skepticism and what’s going on at the frontier of astrophysics.

What are the core tenets of the Big Bang Theory? We explore the frontier of scientific research and what ideas are being contested. We also walk through the scientific process and experimentations. Could the Big Bang just be a small piece of a bigger theory? Learn about Vulcan, the hypothetical planet pulling on Mercury that was invented to save Newton’s Laws. When Einstein’s relativity came along, why didn’t Newtonian physics go away?

Continue reading “YouTube: Are we rethinking the Big Bang?” »

In our common experience, you can’t get something for nothing. In the quantum realm, something really can emerge from nothing.

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Hello and welcome! My name is Anton and in this video, we will talk about new updates from James Webb Space Telescope.
Links:
https://arxiv.org/abs/2207.11658
https://webb.nasa.gov/

https://arxiv.org/abs/2208.14990

Continue reading “More Major Updates From James Webb Telescope and Cool Discoveries” »

“We put nanotubes inside of bacteria,” says Professor Ardemis Boghossian at EPFL’s School of Basic Sciences. “That doesn’t sound very exciting on the surface, but it’s actually a big deal. Researchers have been putting nanotubes in mammalian cells that use mechanisms like endocytosis, that are specific to those kinds of cells. Bacteria, on the other hand, don’t have these mechanisms and face additional challenges in getting particles through their tough exterior. Despite these barriers, we’ve managed to do it, and this has very exciting implications in terms of applications.”

Boghossian’s research focuses on interfacing artificial nanomaterials with biological constructs, including living cells. The resulting “nanobionic” technologies combine the advantages of both the living and non-living worlds. For years, her group has worked on the nanomaterial applications of single-walled carbon nanotubes (SWCNTs), tubes of carbon atoms with fascinating mechanical and optical properties.

These properties make SWCNTs ideal for many novel applications in the field of nanobiotechnology. For example, SWCNTs have been placed inside mammalian cells to monitor their metabolisms using near-infrared imaging. The insertion of SWCNTs in mammalian cells has also led to new technologies for delivering therapeutic drugs to their intracellular targets, while in plant cells they have been used for genome editing. SWCNTs have also been implanted in living mice to demonstrate their ability to image biological tissue deep inside the body.