Herd Immunity Is The Idea That If Enough People Get Immunized Against A Disease, They’ll Create Protection

Redrawing the brain’s motor map

Neuroscientists at Emory have refined a map showing which parts of the brain are activated during head rotation, resolving a decades-old puzzle. Their findings may help in the study of movement disorders affecting the head and neck, such as cervical dystonia and head tremor.

The results were published in Journal of Neuroscience.

In landmark experiments published in the 1940s and 50s, Canadian neurosurgeon Wilder Penfield and colleagues determined which parts of the motor cortex controlled the movements of which parts of the body.

Penfield stimulated the brain with electricity in patients undergoing epilepsy surgery, and used the results to draw a “motor homunculus”: a distorted representation of the human body within the brain. Penfield assigned control of the neck muscles to a region between those that control the fingers and face, a finding inconsistent with some studies that came later.

Using modern functional MRI (magnetic resonance imaging), researchers at Emory University School of Medicine have shown that the neck’s motor control region in the brain is actually between the shoulders and trunk, a location that more closely matches the arrangement of the body itself.

“We can’t be that hard on Penfield, because the number of cases where he was able to study head movement was quite limited, and studying head motion as he did, by applying an electrode directly to the brain, creates some challenges,” says lead author Buz Jinnah, MD, professor of neurology, human genetics and pediatrics at Emory University School of Medicine.

The new location for the neck muscles makes more sense, because it corresponds to a similar map Penfield established of the sense of touch (the somatosensory cortex), Jinnah says.

Participants in brain imaging studies need to keep their heads still to provide accurate data, so volunteers were asked to perform isometric muscle contraction. They attempted to rotate their heads to the left or the right, even though head movement was restricted by foam padding and restraining straps.

First author Cecilia Prudente, a graduate student in neuroscience who is now a postdoctoral associate at the University of Minnesota, developed the isometric head movement task and obtained internal funding that allowed the study to proceed.

She and Jinnah knew that isometric exercises for the wrist activated the same regions of the motor cortex as wrist movements, and used that as a reference point in their study. During brain imaging, they were able to check that particular muscles were being tensed by directly monitoring volunteers’ muscles electronically.

When volunteers contracted their neck muscles, researchers were able to detect activation in other parts of the brain too, such as the cerebellum and the basal ganglia, which are known to be involved in movement control. This comes as no surprise, Jinnah says, since these regions also control movements of the hands and other body parts.

Prudente, Jinnah and colleagues have conducted a similar study with cervical dystonia patients, with the goal of comparing the patterns of brain activation between healthy volunteers and the patients. Cervical dystonia is a painful condition in which the neck muscles contract involuntarily and the head posture is distorted.

“These results may help guide future studies in humans and animals, as well as medical or surgical interventions for cervical dystonia and other disorders involving abnormal head movements,” Prudente says.

TYPES OF COLOR-BLINDNESS

1. Normal vision

2.  Deuteranopia 

3.  Tritanopia

4. Monochromacy - An extremely rare type of color-blindness in which sufferers can see only in shades of grey, and perceive no color at all. About 1 in 33,000 people is born with this condition.

(Source)

Mars in the Loop : This composite of images spaced some 5 to 9 days apart, from late April (bottom right) through November 5 (top left), traces the retrograde motion of ruddy-colored Mars through planet Earth’s night sky. To connect the dots and dates in this 2018 Mars retrograde loop, just slide your cursor over the picture (and check out this animation). But Mars didn’t actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the motion of the Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. On July 27, Mars was near its favorable 2018 parihelic opposition, when Mars was closest to the Sun in its orbit while also opposite the Sun in Earth’s sky. For that date, the frame used in this composite was taken during the total lunar eclipse. via NASA

Flying to New Heights With the Magnetospheric Multiscale Mission

A mission studying Earth’s magnetic field by flying four identical spacecraft is headed into new territory. 

The Magnetospheric Multiscale mission, or MMS, has been studying the magnetic field on the side of Earth facing the sun, the day side – but now we’re focusing on something else. On February 9, MMS started the three-month-long process of shifting to a new orbit. 

One key thing MMS studies is magnetic reconnection – a process that occurs when magnetic fields collide and re-align explosively into new positions. The new orbit will allow MMS to study reconnection on the night side of the Earth, farther from the sun.

Magnetic reconnection on the night side of Earth is thought to be responsible for causing the northern and southern lights.  

To study the interesting regions of Earth’s magnetic field on the night side, the four MMS spacecraft are being boosted into an orbit that takes them farther from Earth than ever before. Once it reaches its final orbit, MMS will shatter its previous Guinness World Record for highest altitude fix of a GPS.

To save on fuel, the orbit is slowly adjusted over many weeks. The boost to take each spacecraft to its final orbit will happen during the first week of April.

On April 19, each spacecraft will be boosted again to raise its closest approach to Earth, called perigee. Without this step, the spacecraft would be way too close for comfort – and would actually reenter Earth’s atmosphere next winter! 

The four MMS spacecraft usually fly really close together – only four miles between them – in a special pyramid formation called a tetrahedral, which allows us to examine the magnetic environment in three dimensions.

But during orbit adjustments, the pyramid shape is broken up to make sure the spacecraft have plenty of room to maneuver. Once MMS reaches its new orbit in May, the spacecraft will be realigned into their tetrahedral formation and ready to do more 3D magnetic science.

Learn more about MMS and find out what it’s like to fly a spacecraft.

The Hubble Space telescope just sent back a new photo of the Twin Jet Nebula. Here’s what it looked like in 1997:

And now …

Whoa. But wait, we also got an updated image of the merging galaxies NGC 6240. What it looked like in 2008:

And today:

Science, you’re the best. Oh, and the explanation behind those merging galaxies and their black holes is wild.

I saw this and thought of @fleamontpotter.

Why we need GMOs to survive climate change

Genetically modified organisms get a bad rap for many reasons, but we’ve actually been genetically altering what we eat since the dawn of human history.

“For 10,000 years, we have altered the genetic makeup of our crops,”explains UC Davis plant pathology professor Pamela Ronald.

“Today virtually everything we eat is produced from seeds that we have genetically altered in one way or another.” (You can read more about Ronald’s thoughts on genetically engineered food here.)

Right now her focus is on rice. It’s one of our basic crops and without it, we would struggle to feed much of the world.

With climate change, we’re seeing an increase in flooding in places like India and Bangladesh, which makes it harder to grow this important food staple.

So Ronald and her lab have developed a flood-tolerant strain of rice. It’s known as Sub1a or “scuba rice” and millions of farmers in South Asia are now growing it in their fields. 

Today is National Food Day, a day dedicated to hunger awareness. But as we focus on food insecurity, we need to talk more about how global warming will make the problem worse.

As our climate continues to heat up, it has huge impacts on what foods we are able to grow. Will our crops be able to survive droughts and floods? The University of California leads six labs that are working to develop other climate-resilient crops including chickpea, cowpea and millet.

Find out what other scientists are doing to improve our food.

fMRI differences in brain activity in prefrontal cortex.