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neurosciencestuff:

Dying brain cells cue new brain cells to grow in songbird

Brain cells that multiply to help birds sing their best during breeding season are known to die back naturally later in the year. For the first time researchers have described the series of events that cues new neuron growth each spring, and it all appears to start with a signal from the expiring cells the previous fall that primes the brain to start producing stem cells.

If scientists can further tap into the process and understand how those signals work, it might lead to ways to exploit these signals and encourage replacement of cells in human brains that have lost neurons naturally because of aging, severe depression or Alzheimer’s disease, said Tracy Larson, a University of Washington doctoral student in biology. She’s lead author of a paper in the Sept. 23 Journal of Neuroscience on brain cell birth that follows natural brain cell death.

Neuroscientists have long known that new neurons are generated in the adult brains of many animals, but the birth of new neurons – or neurogenesis – appears to be limited in mammals and humans, especially where new neurons are generated after there’s been a blow to the head, stroke or some other physical loss of brain cells, Larson said. That process, referred to as “regenerative” neurogenesis, has been studied in mammals since the 1990s.

This is the first published study to examine the brain’s ability to replace cells that have been lost naturally, Larson said.

“Many neurodegenerative disorders are not injury-induced,” the co-authors write, “so it is critical to determine if and how reactive neurogenesis occurs under non-injury-induced neurodegenerative conditions.”

The researchers worked with Gambel’s white-crowned sparrows, a medium-sized species 7 inches (18 centimeters) long that breeds in Alaska, then winters in California and Mexico. Sometimes in flocks of more than 100 birds, they can be so plentiful in parts of California that they are considered pests. The ones in this work came from Eastern Washington.

Like most songbirds, Gambel’s white-crowned sparrows experience growth in the area of the brain that controls song output during the breeding season when a superior song helps them attract mates and define their territories. At the end of the season, probably because having extra cells exacts a toll in terms of energy and steroids they require, the cells begin dying naturally and the bird’s song degrades.

Gambel’s white-crowned sparrows are particularly good to work with because their breeding cycle is closely tied to the amount of sunlight they receive. Give them 20 hours of light in the lab, along with the right increase of steroids, and they are ready to breed. Cut the light to eight to 12 hours and taper the steroids, the breeding behavior ends.

“As the hormone levels decrease, the cells in the part of the brain controlling song no longer have the signal to ‘stay alive,’” Larson said. “Those cells undergo programmed cell death – or cell suicide as some call it. As those cells die it is likely they are releasing some kind of signal that somehow gets transmitted to the stem cells that reside in the brain. Whatever that signal is then triggers those cells to divide and replace the loss of the cell that sent the signal to begin with.”

The next spring, all that’s needed is for steroids to ramp up and new cells start to proliferate in the song center of the brain.

“This paper doesn’t describe the exact nature of the signals that stimulate proliferation,” Larson said. “We’re just describing the phenomenon that there is this connection between cells dying and this stem cell proliferation. Finding the signal is the next step.”

“Tracy really nailed this down by going in and blocking cell death at the end of the breeding season,” said Eliot Brenowitz, UW professor of psychology and of biology, and co-author on the paper. “There are chemicals you can use to turn off the cell suicide pathway. When this was done, far fewer stem cells divided. You don’t get that big uptick in new neurons being born. That’s important because it shows there’s something about the cells dying that turns on the replacement process.’

“There’s no reason to think what goes on in a bird brain doesn’t also go on in mammal brains, in human brains,” Brenowitz said. “As far as we know, the molecules are the same, the pathways are the same, the hormones are the same. That’s the ultimate purpose of all this, to identify these molecular mechanisms that will be of use in repairing human brains.”

In mammals, the area of the brain that controls the sense of smell and the one that is thought to have a role in memories can produce tiny numbers of new brain cells but it is not understood how or why. The numbers of new cells is so low that trying to identify and quantify whether dying cells are being replaced and if so, the steps that are involved, is much more difficult than when using a songbird like Gambel’s white-crowned sparrow, Larson and Brenowitz said.

Muy interesante

photomgraphy:

beben-eleben:

How to get a boyfriend

lol

That’s funny

sosuperawesome:

Mini paintings on cedar by Cathy McMurray on Etsy

(via photomgraphy)

ultrafacts:

Source If you want more facts, follow Ultrafacts

theartofanimation:

Stephan Martiniere

Interesting graphic designs

(via broadacre)

mortisia:

Classic Horror Films 1 / 2
edit by me / click pictures to enlarge

1. Dracula (1931)
2. Frankenstein (1931)
3. The Phantom of the Opera (1925)

4. The Mummy (1932)
5. The Invisible Man (1933)
6. The Wolf Man (1941)
7. Creature from the Black Lagoon (1954)
8. 
London After Midnight (1927)
9. House of Usher (1960)
10. Dr. Jekyll and Mr. Hyde (1931)

The order is not chronological or alphabetical. Truly irrelevant when you have to deal with masterpieces. 

(via broadacre)

neurosciencestuff:

Scientists “fingerprint” a culprit in depression, anxiety and other mood disorders

According to the World Health Organization, such mood disorders as depression affect some 10% of the world’s population and are associated with a heavy burden of disease. That is why numerous scientists around the world have invested a great deal of effort in understanding these diseases. Yet the molecular and cellular mechanisms that underlie these problems are still only partly understood.

The existing anti-depressants are not good enough: Some 60-70% of patients get no relief from them. For the other 30-40%, that relief is often incomplete, and they must take the drugs for a long period before feeling any effects. In addition, there are many side effects associated with the drugs. New and better drugs are clearly needed, an undertaking that requires, first and foremost, a better understanding of the processes and causes underlying the disorders.

The Weizmann Institute’s Prof. Alon Chen, together with his then PhD student Dr. Orna Issler, investigated the molecular mechanisms of the brain’s serotonin system, which, when misregulated, is involved in depression and anxiety disorders. Chen and his colleagues researched the role of microRNA molecules (small, non-coding RNA molecules that regulate various cellular activities) in the nerve cells that produce serotonin. They succeeded in identifying, for the first time, the unique “fingerprints” of a microRNA molecule that acts on the serotonin-producing nerve cells. Combining bioinformatics methods with experiments, the researchers found a connection between this particular microRNA, (miR135), and two proteins that play a key role in serotonin production and the regulation of its activities. The findings appeared today in Neuron.

The scientists noted that in the area of the brain containing the serotonin-producing nerve cells, miR135 levels increased when antidepressant compounds were introduced. Mice that were genetically engineered to produce higher-than-average amounts of the microRNA were more resistant to constant stress: They did not develop any of the behaviors associated with chronic stress, such as anxiety or depression, which would normally appear. In contrast, mice that expressed low levels of miR135 exhibited more of these behaviors; in addition, their response to antidepressants was weaker. In other words, the brain needs the proper miR135 levels – low enough to enable a healthy stress response and high enough to avoid depression or anxiety disorders and to respond to serotonin-boosting antidepressants. When this idea was tested on human blood samples, the researchers found that subjects who suffered from depression had unusually low miR135 levels in their blood. On closer inspection, the scientists discovered that the three genes involved in producing miR135 are located in areas of the genome that are known to be associated with risk factors for bipolar mood disorders.

These findings suggest that miR135 could be a useful therapeutic molecule – both as a blood test for depression and related disorders, and as a target whose levels might be raised in patients. Yeda Research and Development Co. Ltd., the technology transfer arm of the Weizmann Institute, has applied for a patent connected to these findings and recently licensed the rights to miCure Therapeutics to develop a drug and diagnostic method. After completing preclinical trials, the company hopes to begin clinical trials in humans.

spring-of-mathematics:

Geometry & Physics: Rolling - A type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact with each other without sliding.

Image 1: Four objects racing down a plane while rolling without slipping. From back to front: spherical shell (red), solid sphere (orange), cylindrical ring (green) and solid cylinder (blue). The time for each object to reach the finishing line depends on their moment of inertia around the rolling axis.

Image 2, 3: Common moments of inertia &  Rolling Farms by Jason Arney.

Source: Rolling on Wikipedia & Common moments of inertia at ph.utexas.edu

nice!!

(via mathmajik)

instagram:

The Whimsically Macabre Scenes of @__remmidemmi

To see more of Sandro’s explorations of “bodies with no regret,” follow @__remmidemmi on Instagram.

In his macabre, tragicomic photo series, Italian photographer Sandro Giordoan (@__remmidemmi) explores the willingness of people to put the safety of material objects before their own well-being.

When conceiving the project, _IN EXTREMIS (bodies with no regret), Sandro drew from personal experience. “Last summer I had a small but tough bicycle accident,” he explains. “I lost 30% of my right hand’s functions because I never let go of the object I was holding as I fell.”

When, shortly after, a friend broke his leg to prevent his smartphone from falling in water, Sandro became concerned. “We live in a time where we risk material things becoming more important than our own lives, and this is really worrying.”

Sandro channeled his concern into crafting meticulous and whimsical photos. “I immediately felt the urgency to capture the moment of impact. I wanted to talk about obsessions, neurosis and frailties of our times through my personal experience.” The resulting photos are at once humorous and haunting.

Many think that the wildly contorted bodies in Sandro’s photos are dolls or dummies. Not so, says Sandro. “I work exclusively with professional actors who are able to position themselves in anatomically impossible poses because they are trained to use their bodies to communicate.”