McGill researchers uncover crucial link between hippocampus and prefrontal cortex
A clue to understanding certain cognitive and mental disorders may involve two parts of the brain which were previously thought to have independent functions, according to a McGill University team of researchers led by Prof. Yogita Chudasama, of the Laboratory of Brain and Behavior, Department of Psychology. The McGill team discovered a critical interaction between two prominent brain areas: the hippocampus, a well-known memory structure made famous by Dr. Brenda Milner’s patient H.M., and the prefrontal cortex, which is involved in decision-making and inhibiting inappropriate behaviours.
“We had always thought that the hippocampus and the prefrontal cortex functioned independently,” says Prof. Chudasama. “Our latest study provides the first indication that that is not the case.”
The team’s finding, just published in the Journal of Neuroscience, reveals a critical interaction between these two brain areas and the control of behavior, and may advance the treatment of some cognitive and mental disorders including schizophrenia, and depression. The interaction between the hippocampus and the prefrontal cortex shows that brain circuits function not just as specific parts of the brain, but are linked together and work as a system.
“Although the prefrontal cortex has long been known to be the driving force that steers our behavior, pushing us to make good decisions and withhold improper actions, it turns out that it can’t do this unless it interacts with the hippocampus,” added Prof. Chudasama. “We found that when we prevented these two structures from communicating with each other, like humans with compulsive disorders, rats persisted with behaviours that were not good for them; they didn’t correct their errant behaviours and could not control their natural urges.
The ability to control impulsive urges or inhibit our actions allows us to interact normally in personal or social situations, and this type of behaviour depends on the normal interaction of the hippocampus and the prefrontal cortex. This result provides a means for understanding the neural basis for social and cognitive deficits in disorders of brain and behaviour, such as those with frontotemporal dementia”, concludes Prof. Chudasama.
Research from Washington University in St. Louis has identified variations in brain scans that they believe identify portions of the brain that are responsible for intelligence.
As suspected (and as explained by cartoons) brain size does play a small role; they said that brain size accounts for 6.7 percent of variance in intelligence. Recent research has placed the brain’s prefrontal cortex, a region just behind the forehead, as providing for 5 percent of the variation in intelligence between people.
Artificial jellyfish built from rat cells
Bioengineers have made an artificial jellyfish using silicone and muscle cells from a rat’s heart. The synthetic creature, dubbed a medusoid, looks like a flower with eight petals. When placed in an electric field, it pulses and swims exactly like its living counterpart.
“Morphologically, we’ve built a jellyfish. Functionally, we’ve built a jellyfish. Genetically, this thing is a rat,” says Kit Parker, a biophysicist at Harvard University in Cambridge, Massachusetts, who led the work.
When an electric field is applied across the structure, the muscle contracts rapidly, compressing the medusoid and mimicking a jellyfish’s power stroke. The elastic silicone then pulls the medusoid back to its original flat shape, ready for the next stroke.
When placed between two electrodes in water, the medusoid swam like the real thing. It even produced water currents similar to those that wash food particles into jellyfish’s mouths. “We thought if we’re really good at this, we’re going to recreate that vortex, and we did,” says Parker. “We took a rat apart and rebuilt it as a jellyfish.”
The team now plans to build a medusoid using human heart cells. The researchers have filed a patent to use their design, or something similar, as a platform for testing drugs.
Extract from Nature.com
Gif made from this Youtube video: Parker et al/ Nature Biotechnology
There’s one gif. Where’s my gifset?
Squeek Squeek Glub Glub
Sounds like a good band name, eh?
Simulations of how we think the universe is organized, astrophysically speaking, show patterns resembling nodes of clustered galaxies connected by filaments of dense matter. We’ve found plenty of the galaxy clusters, but the filaments have been harder to actually observe. That’s because they are likely made of dark matter, which neither emits or absorbs light (and is therefore invisible to we mere humans).
But scientists may have witnessed the effect of one of these filaments recently, marking the first time that dark matter has been observed connecting galaxy clusters. As Matthew Francis reports:
The researchers used archival data from the 8.2 meter Subaru telescope in Hawaii, which includes visible and infrared observations of the supercluster. These were scanned to look for subtle changes in the light from objects behind the clusters. These can be signs of weak gravitational lensing, which would reveal the distribution of dark matter near the clusters.
Gravitational lensing basically means that something invisible with mass, like dark matter, is bending the light from the cluster of galaxies. So although we can’t see the dark matter, we can see it affecting the light’s path and take a pretty good guess it is there.
I bet these guys wish they hadn’t announced this in the same week as the Higgs boson, but hey … can’t win ‘em all. It gives support to the idea that our universe could be built on enormous webs of dark matter, and where these filaments and strands intersect, there is where gravity pulls galaxies together to form the clusters of stars and visible matter that we see every time we look up at night.
If you keep going around the universe, will you end up where you started?
Is the universe flat or spherical or saddle-shaped, and what do any of these things really mean? Do we live in a Pac-Man universe, or an infinite one?
[ … ]
Why should our universe be curved at all? For the same reason that any sort of space-time gets curved in our crazy universe: there’s stuff in it. In case you’ve forgotten, one of the major predictions of Einstein’s theory of general relativity is that mass and energy curve space and time.
The same is true for the universe — our human 3-d universe — as a whole. If there’s too little stuff the universe is saddle-shaped. Put in too much, and the universe is spherical. But put in just the right amount (and this seems to be the case for us) and the universe will be flat. As we used to rather cheesily put it, “Density is destiny.”
[ … ]
String Theory says that all the notes on a vibrating string correspond to a particle. That to an electron is actually a rubber band; a very tiny rubber band. but if you twang this rubber band and the rubber band vibrates at a different frequency, it turns into a quark. And you twang it again and it turns into a neutrino. So, how many musical notes are there? An infinite. How many musical notes are there on a string? An infinite number. And that may explain why we have so many subatomic particles. They are nothing but musical notes.
So, physics are nothing but the laws of harmonies on a string. Chemistry is nothing but the melodies you can play on vibrating strings. And the mind of God, the mind of God that Einstein worked on for the last 30 years of his life, the mind of God would be cosmic music. Cosmic music resonating through 11 dimensional hyperspace.Micho Kaku, Theoretical Physicist (via randomglory)
UNDER the intense stare of the Kepler space telescope, more and more planets similar to our own are revealing themselves to us. We haven’t found one exactly like Earth yet, but so many are being discovered that it appears the galaxy must be teeming with habitable planets. These discoveries are bringing an old paradox back into focus. As physicist Enrico Fermi asked in 1950, if there are many suitable homes for life out there and alien life forms are common, where are they all? More than half a century of searching for extraterrestrial intelligence has so far come up empty-handed. Of course, the universe is a very big place. Even Frank Drake’s famously optimistic “equation” for life’s probability suggests that we will be lucky to stumble across intelligent aliens: they may be out there, but we’ll never know it. That answer satisfies no one, however. There are deeper explanations. Perhaps alien civilisations appear and disappear in a galactic blink of an eye, destroying themselves long before they become capable of colonising new planets. Or maybe life very rarely gets started even when conditions are perfect.
OR Intelligent civilizations have technology that has evolved beyond human comprehension, so much that our own technology would have trouble detecting it.