Dear readers of the Science Fix: real life is interfering with my online life in a big way (but in a good way) and it’s becoming increasingly difficult for me to write this blog in a timely fashion. I’m hoping to be able to still post a Science Fix at least a couple of times a month, but I may not be able to do in the future, because I’m going to get increasingly busy doing science as opposed to writing about it.
IMAGE OF THE WEEK
Hippocampus in a “brainbow” mouse, by Tamily Weissman, Harvard University: the photo shows individual neurons of the dentate gyrus, a layer of the hippocampus. You can see each individual neuron in a different color because the mouse carries engineered DNA expressing three different fluorescent proteins, but only one of them can be expressed per cell. I love the dendrites extending into the outer layer, in an explosion of different colors.
VIDEO OF THE WEEK
Midway trailer by Chris Jordan. I'm not telling you what this is about. You know. Warning: if you watch this and by the end your eyes are not at the very least moist, there is something wrong with you. Spread the video around, and always think about the consequences of your actions, even those that seem irrelevant or inconsequential in your every day living.
Courtesy of Michel who posted in Green Atheists. Please join the group.
But I’m not so cruel as to leave you with such sadness in your heart: watch this other video, courtesy of Michel once again. It will lift your spirits and remind you of the beauty of the plant kingdom and how very much alive it is.
The Human Connectome Project and the Brain Activity Map Project: We have discussed the HCP here and the BAM here. What are these two projects and why are they exciting? These are two large scale projects, involving multiple institutions, and they are being funded by the National Institutes of Health. They are similar in structure to the Human Genome Project, which a decade or so ago, resulted in the sequencing of the entire human genome. And before fiscal conservatives start screaming that Americans don't have any money to spend in this kind of projects, Obama reminded us that the HGP gave us $140 return for every dollar spent by the US government, through new technologies and job creations. I'm one of those people to have benefited from the HGP, my job is based on those discoveries and those technologies. The Human Connectome Project started in 2009 and its goal isto map the neural connections within the human in their entirety. A human brain contains ~100 billion neurons, each with about 10,000 connections, so it’s a daunting task. There are many institutions involved. The brains of 1,200 healthy adults are being scanned to map the neural architecture, and numerous publications have resulted from this project already Researchers are also collect genetic and behavioral data from the study subjects in order to correlate these factors with the neural architecture. The Brain Activity Map project will cost more >$300 million/year and will run for ten years. This project plans to use novel non-invasive methods derived from nanotechnology, to sense the activity of single neurons, combined with methods of neuroimaging, to map the activity (not just the connections) every neuron in the human brain. This is an ambitious project to say the least. It is expected that as the Human Genome Project was a boon for new technologies to sequence DNA, this project will do the same for nanotechnology and other technology development areas, not to mention for the study of mental illnesses. The ultimate goal would perhaps be to understand consciousness. We all know what that is, but it hasn't been described yet.
How to scare someone who knows no fear. The amygdala is a small area of our brain that mediates fear responses. People with a damaged amygdala cannot experience fear. There is an extremely rare genetic condition, Urbach-Wiethe disease, in which the amygdala hardens and shrivels up. Patients who suffer from this disease can watch horror movies, look at spiders and snakes, and other scary stuff, without feeling any fear. So when SM, a 44-year old woman suffering from Urbach-Wiethe disease, was told she was going to inhale a non-lethal dose of CO2, known to elicit a strong fear reaction in people and mice with intact amygdalas, she was not scared. However, within seconds of breathing in the CO2 mixture, she panicked and cried out, overwhelmed by feeling of suffocation, just like people with a normal amygdala. SM had not experienced fear since she was a child, when her amygdala became non-functional as a consequence of her disease. Neuroscientists just published the results of these experiments in Nature Neuroscience. They used the CO2 inhalation test on SM, two other patients with the same disease, and 12 healthy control volunteers. They were surprised to find that the patients with amygdala-damage were in fact, more panicky and fearful than the controls, after inhaling CO2, though the healthy volunteers were scared beforehand. These experiments clearly show that the amygdala does not mediate all fear responses, and that panic (a primal response when survival is at stake) and fear may be two separate responses mediated by different brain regions. The neuroscientists plan to use functional imaging to pinpoint the brain regions involved in the amygdala-independent panic response; they speculate that these may include the brainstem, diencephalon and the insular cortex, regions that mediate bodily awareness. The research can open new roads to understand and treat panic attacks and other anxiety-related disorders.
ENDLESS FORMS MOST BEAUTIFUL
Dolphins may call each other by name. Dolphins use “signature whistles” to identify themselves, that they learn from their mothers, but are they the equivalent of dolphin names? In a new study, published Feb. 19 in Proceedings of the Royal Society B, Scottish scientists addressed the possible meaning of the whistles. Are they a display of territorial aggression? Or used by males to court females guarded by other males? Or is it really an information exchange, similar to a dialog? They used dolphins captured for the purpose of population monitoring, in Florida. The animals were separated from other members of the pod but they could still hear each other. These dolphins used their captured friends’ and relatives’ signature whistles to keep in touch with each other. Interestingly, the copying wasn’t exact, but included modulations at the beginning and end of each call, seemingly adding additional information. This suggests that the animals are using learned, rather than instinctively understood sounds, to mentally represent other objects and individuals. This is similar to what we humans do. Of course, other explanations of the behavior are possible, this level of sophistication is possible, since these animals have rich social lives and are very intelligent.
Stereo smelling in moles. Stereo sensing is very common in mammals, but it's mostly restricted to stereovision or stereo hearing. The question of whether mammals can smell in stereo has been debated for a while, with some researchers thinking that both rats and humans have the capability of smelling in stereo, meaning, the ability to detect differences in smell between one nostril and the other. A team of neuroscientists at Vanderbilt has now demonstrated that the common American mole (Scalopus aquaticus) can smell in stereo. They built a chamber containing 15 food wells arrayed in a semicircle, and they placed a piece of earthworm (their main food source) in one of them. Moles took a very short time to smell their way through the chamber and zero in the one containing an earthworm. But if they plugged their left nostril, the moles got confused and kept moving to the right. If the right nostril was plugged, the adorable odd looking critters tended to move to the left. And it took them longer to find the tasty treat. When the investigators inserted nostril tubes that transposed the odors between the left and the right nostrils, the moles were totally confused and often could not find the earthworm at all. An underground tunnel built to test the same principle showed the same results. It is pretty clear that these animals are using the odors coming into their right and left nostrils as guides for localizing the source of the smell, in a very similar way as we use our stereo hearing to localize the source of a sound.
Unique proteins allow newts to regenerate their limbs. The red spotted newt (Notophthalmus viridescens) has an astonishing ability to regenerate lost tissue, including heart muscle, parts of its central nervous system and even the lens of its eye. The hypothesis is that the capacity for regeneration is common to all multicellular organisms, and thus ancient. If this was the case, we could learn how to regenerate human tissue or even organs or limbs by animals that are good at regeneration. But sequencing the transcriptome (the totality of protein-encoding RNAs expressed by an organism or cell) of this newt’s tissues, both primary and regenerating, threw a wet towel on that idea. It turns out that the newt's capacity for regeneration is of relatively recent evolution. The newt has > 800 RNAs that are unique to this animal, not found in any other vertebrate, and many of those exclusive to regenerating tissue. The scientists involved in the study say this is evidence that there may be no ancestral program that can be reawakened to achieve regeneration. However, this does not mean that mammal tissues cannot be induced to regenerate to a greater degree or speed, in the future. It’s also possible that there actually is an ancestral program for regeneration, but that newts have acquired extra abilities through evolution.
Russian meteor largest in a century. I assume you have all heard about the Russian meteor that exploded over the region of Chelyabinsk in Russia, near the southern Ural Mountains. The fireball was quite a blinding sight (if such a thing makes sense). The explosion was equivalent to a nuclear blast in power, it blew thousands of windows and ~ 700 reported injuries as a result. Check out the discussion for some awe-striking videos taken by the locals. In a way, I wish I'd been there to witness it, but not close enough to be hurt by exploding glass shards! No warning was possible because the meteor was too small (<100 meters) to be detected by telescopes until it hit the atmosphere. Fortunately it exploded in the upper atmosphere, or the damage would have been far worse. The region is not very populated either, so that is lucky too. Also this Nature News article is full of great information on this extraordinary event.
Nice Tweet from:
Finally, evidence for Hollywood that not all asteroids hit major cities of the United States.