YOUR DOCTOR COULD GROW A TINY VERSION OF YOUR BRAIN IN A DISH

“This new technique allows researchers to use the same stem cells from a patient’s skin to create a three-dimensional complex of neurons, as well as their supporting glial cells, that closely resembles the structure of the actual brain. The process requires fewer steps than previous methods, and the “budding cortex” may also lend itself to brain slicing, which, when it’s more sophisticated, could allow researchers to get a better look a how circuitry disorders affect the brain.”

5

As Virginia Hughes noted in a recent piece for National Geographic’s Phenomena blog, the most common depiction of a synapse (that communicating junction between two neurons) is pretty simple:

Signal molecules leave one neuron from that bulby thing, float across a gap, and are picked up by receptors on the other neuron. In this way, information is transmitted from cell to cell … and thinking is possible.

But thanks to a bunch of German scientists - we now have a much more complete and accurate picture. They’ve created the first scientifically accurate 3D model of a synaptic bouton (that bulby bit) complete with every protein and cytoskeletal element.

This effort has been made possible only by a collaboration of specialists in electron microscopy, super-resolution light microscopy (STED), mass spectrometry, and quantitative biochemistry.

says the press release. The model reveals a whole world of neuroscience waiting to be explored. Exciting stuff!

You can access the full video of their 3D model here.

Credit: Benjamin G. Wilhelm, Sunit Mandad, Sven Truckenbrodt, Katharina Kröhnert, Christina Schäfer, Burkhard Rammner, Seong Joo Koo, Gala A. Claßen, Michael Krauss, Volker Haucke, Henning Urlaub, Silvio O. Rizzoli

22 July 2013

Pictures in Mind

Neuroscientists have an extraordinary challenge to see how the brain works. It functions so quickly and is so densely populated with neuron networks and their supporting cells, technology is not yet advanced enough to allow us to see everything at once. But new methods and technologies are constantly evolving; here’s an image of a whole Zebrafish brain caught in the process sending messages. Every bright spot in the picture is an individual neuron filled with calcium – an ion that floods into the nerve cell when it sends a message. This method enables researchers to see how the whole brain works together and see how the activation of single neurons add together in the larger network. With methods like this it could be possible to map the function of every neuron network in the brain, helping to pinpoint the cause of disorders like epilepsy or schizophrenia.

Written by Mary-Clare Hallsworth

16 September 2013

Brain-bow

This is a colourful slice through an autopsy sample – a brain taken from an 83 year-old woman. Red, green and blue fluorescent dyes highlight different chemical ‘messages’, called neuropeptides, being sent between brains cells (neurons). Two of these messages (kisspeptin, labelled in red and neurokinin, blue) often work together (shown where their overlapping dyes produce purples splodges) to trigger bursts of gonadotropin-releasing hormone, an important regulator of fertility and reproduction. But this elderly lady’s brain had also been sending a different chemical message (substance P, coloured green) at the same time – and often from the same neurons as kisspeptin (producing yellow splodges) or neurokinin (turquoise), or even in a triple-message combo (white). Neurons carrying substance P are more plentiful in the brains of elderly women than men, suggesting it could play a vital role in ‘rewiring’ hormone regulation in the female brain during the menopause.

Written by John Ankers

“Brainbow” zebra fish.

Neurons are labeled in multiple colors with Brainbow fluorescence microscopy. Three fluorescent proteins (cyan, yellow and red) are randomly taken up by various neurons, offering a palette of dozens of colors to help scientists follow complex neural pathways. Shown here is a five-day-old zebra fish larva viewed from the dorsal side, captured using a 20X objective.

Image credit: Dr. Albert Pan, Harvard University, Cambridge, Mass., U.S.

2

Did Neurons Evolve Twice?

Comb jellies are ancient marine predators whose comb-like cilia refract light as they swim. Biologists are intrigued by their highly unusual nervous systems.

When Leonid Moroz, a neuroscientist at the Whitney Laboratory for Marine Bioscience in St. Augustine, Fla., first began studying comb jellies, he was puzzled. He knew the primitive sea creatures had nerve cells — responsible, among other things, for orchestrating the darting of their tentacles and the beat of their iridescent cilia. But those neurons appeared to be invisible. The dyes that scientists typically use to stain and study those cells simply didn’t work. The comb jellies’ neural anatomy was like nothing else he had ever encountered.

After years of study, he thinks he knows why. According to traditional evolutionary biology, neurons evolved just once, hundreds of millions of years ago, likely after sea sponges branched off the evolutionary tree. But Moroz thinks it happened twice — once in ancestors of comb jellies, which split off at around the same time as sea sponges, and once in the animals that gave rise to jellyfish and all subsequent animals, including us. He cites as evidence the fact that comb jellies have a relatively alien neural system, employing different chemicals and architecture from our own. “When we look at the genome and other information, we see not only different grammar but a different alphabet,” Moroz said.

When Moroz proposed his theory, evolutionary biologists were skeptical. Neurons are the most complex cell type in existence, critics argued, capable of capturing information, making computations and executing decisions. Because they are so complicated, they are unlikely to have evolved twice.

But new support for Moroz’s idea comes from recent genetic work suggesting that comb jellies are ancient — the first group to branch off the animal family tree. If true, that would bolster the chance that they evolved neurons on their own.

The debate has generated intense interest among evolutionary biologists. Moroz’s work does not only call into question the origins of the brain and the evolutionary history of animals. It also challenges the deeply entrenched idea that evolution progresses steadily forward, building up complexity over time.

The First Split

Somewhere in the neighborhood of 540 million years ago, the ocean was poised for an explosion of animal life. The common ancestor of all animals roamed the seas, ready to diversify into the rich panoply of fauna we see today.

Scientists have long assumed that sponges were the first to branch off the main trunk of the animal family tree. They’re one of the simplest classes of animals, lacking specialized structures, such as nerves or a digestive system. Most rely on the ambient flow of water to collect food and remove waste.

Later, as is generally believed, the rest of the animal lineage split into comb jellies, also known as ctenophores (pronounced TEN-oh-fours); cnidarians (jellyfish, corals and anemones); very simple multicellular animals called placozoa; and eventually bilaterians, the branch that led to insects, humans and everything in between.

But sorting out the exact order in which the early animal branches split has been a notoriously thorny problem. We have little sense of what animals looked like so many millions of years ago because their soft bodies left little tangible evidence in rocks. “The fossil record is spotty,” said Linda Holland, an evolutionary biologist at the Scripps Institution of Oceanography at the University of California, San Diego.

Keep reading

6

Tiny chip mimics brain, delivers supercomputer speed

Researchers Thursday unveiled a powerful new postage-stamp size chip delivering supercomputer performance using a process that mimics the human brain.

The so-called “neurosynaptic” chip is a breakthrough that opens a wide new range of computing possibilities from self-driving cars to artificial intelligence systems that can installed on a smartphone, the scientists say.

The researchers from IBM, Cornell Tech and collaborators from around the world said they took an entirely new approach in design compared with previous computer architecture, moving toward a system called “cognitive computing.”

“We have taken inspiration from the cerebral cortex to design this chip,” said IBM chief scientist for brain-inspired computing, Dharmendra Modha, referring to the command center of the brain.

Read more

I wish I had the time to take more classes during undergrad; I could never fit neurobio and its lab into my schedule.

Here is a picture of neurons and their basic parts with really basic definitions. There are a lot of other things about them that aren’t included but this is a start.

Full size.

10

Dazzling Images of the Brain Created by Neuroscientist-Artist ( Livescience )

Greg Dunne

I enjoy Asian art. I particularly love minimalist scroll and screen painting from the Edo period in Japan. I am also a fan of neuroscience. Therefore, it was a fine day when two of my passions came together upon the realization that the elegant forms of neurons (the cells that comprise your brain) can be painted expressively in the Asian sumi-e style. Neurons may be tiny in scale, but they posess the same beauty seen in traditional forms of the medium (trees, flowers, and animals).

3

And the winner is …

Here are some of the winners from Science’s annual Visualization Challenge - you can see lots more here.

  1. Top image: “Invisible Coral Flows” by Vicente I. Fernandez, Orr H. Shapiro, Melissa S. Garren, Assaf Vardi, Roman Stocker (MIT).  The cilia of coral polyps stir up the water, helping them get food and dispose of nutrients.
  2. Middle image: “Stellate leaf hairs on Deutzia scabra” by Stephen Francis Lowry (Steve Lowry Photography). A technique called polarized light microscopy reveals the fine structure of the leaves of Fuzzy Duetzia.
  3. Bottom image: “Cortex in Metallic Pastels” by Greg Dunn, Brian Edwards (Greg Dunn Design), Marty Saggese (SfN), Tracy Bale (UPenn), and Rick Huganir (Johns Hopkins University). Dunn used gold leaf, aluminum and acrylic dye to show the layered cellular structure of the cerebral cortex. Dunn: “The neurons are painted by a technique wherein pigments are blown across the canvas using jets of air, a technique that closely emulates the spontaneous, random branching patterns of actual neurons.”
2

Neuroscientists discover new ‘mini-neural computer’ in the brain

Dendrites, the branch-like projections of neurons, were once thought to be passive wiring in the brain. But now researchers at the University of North Carolina at Chapel Hill have shown that these dendrites do more than relay information from one neuron to the next. They actively process information, multiplying the brain’s computing power.

“Suddenly, it’s as if the processing power of the brain is much greater than we had originally thought,” said Spencer Smith, PhD, an assistant professor in the UNC School of Medicine.

His team’s findings, published October 27 in the journal Nature, could change the way scientists think about long-standing scientific models of how neural circuitry functions in the brain, while also helping researchers better understand neurological disorders.

“Imagine you’re reverse engineering a piece of alien technology, and what you thought was simple wiring turns out to be transistors that compute information,” Smith said. “That’s what this finding is like. The implications are exciting to think about.”

Axons are where neurons conventionally generate electrical spikes, but many of the same molecules that support axonal spikes are also present in the dendrites. Previous research using dissected brain tissue had demonstrated that dendrites can use those molecules to generate electrical spikes themselves, but it was unclear whether normal brain activity involved those dendritic spikes. For example, could dendritic spikes be involved in how we see?

The answer, Smith’s team found, is yes. Dendrites effectively act as mini-neural computers, actively processing neuronal input signals themselves.

Directly demonstrating this required a series of intricate experiments that took years and spanned two continents, beginning in senior author Michael Hausser’s lab at University College London, and being completed after Smith and Ikuko Smith, PhD, DVM, set up their own lab at the University of North Carolina. They used patch-clamp electrophysiology to attach a microscopic glass pipette electrode, filled with a physiological solution, to a neuronal dendrite in the brain of a mouse. The idea was to directly “listen” in on the electrical signaling process.

“Attaching the pipette to a dendrite is tremendously technically challenging,” Smith said. “You can’t approach the dendrite from any direction. And you can’t see the dendrite. So you have to do this blind. It’s like fishing if all you can see is the electrical trace of a fish.” And you can’t use bait. “You just go for it and see if you can hit a dendrite,” he said. “Most of the time you can’t.”

But Smith built his own two-photon microscope system to make things easier.

Once the pipette was attached to a dendrite, Smith’s team took electrical recordings from individual dendrites within the brains of anesthetized and awake mice. As the mice viewed visual stimuli on a computer screen, the researchers saw an unusual pattern of electrical signals – bursts of spikes – in the dendrite.

Smith’s team then found that the dendritic spikes occurred selectively, depending on the visual stimulus, indicating that the dendrites processed information about what the animal was seeing.

To provide visual evidence of their finding, Smith’s team filled neurons with calcium dye, which provided an optical readout of spiking. This revealed that dendrites fired spikes while other parts of the neuron did not, meaning that the spikes were the result of local processing within the dendrites.

Study co-author Tiago Branco, PhD, created a biophysical, mathematical model of neurons and found that known mechanisms could support the dendritic spiking recorded electrically, further validating the interpretation of the data.

“All the data pointed to the same conclusion,” Smith said. “The dendrites are not passive integrators of sensory-driven input; they seem to be a computational unit as well.”

His team plans to explore what this newly discovered dendritic role may play in brain circuitry and particularly in conditions like Timothy syndrome, in which the integration of dendritic signals may go awry.

Image1: A network of pyramidal cells in the cerebral cortex. These neurons have been simulated using a computer program which captures the beautiful dendritic architecture of real pyramidal cells. These dendrites have now been shown to carry out sophisticated computations on their inputs. Credit: UCL.

Image2: This is a dendrite, the branch-like structure of a single neuron in the brain. The bright object from the top is a pipette attached to a dendrite in the brain of a mouse. The pipette allows researchers to measure electrical activity, such as a dendritic spike, the bright spot in the middle of the image. Credit: Spencer Smith