magnetic-imaging

So there’s loads of different neuroimaging methods out there that are used depending on what it is you’re looking for! I’ve had the privilege of actually studying it and there’s so so many different types more than just functional MRI that people don’t really know about so here are a few and what they’re used for an how they work.

MRI - Magnetic Resonance Imaging

The most commonly used form of neuroimaging and for good reason. MRI uses the body’s tissue density and magnetic properties of water to visualise structures within the body. It has really incredible spatial and temporal quality and is predominantly used in neuroscience/neurology for looking for any structural abnormalities such as tumours, tissue degeneration etc. It’s fantastic a fantastic form of imaging and is used in numerous amounts of research.

Functional MRI (fMRI)

These images are captured the same way as MRI but the quality is a little bit lower because the aim is to capture function (those blobs you can see) as quickly and accurately as possible so the quality is compromised a little bit. Nonetheless, fMRI usually uses the BOLD response to measure function. It measures the amount of activity in different areas of the brain when doing certain things, so during a memory test for example, and it does that by measuring the amount oxygen that a certain area requires. The increased oxygen is believed to be sent to an area where there is more neuronal activity, so it’s not a direct measurement but rather we’re looking at a byproduct. There are numerous studies trying to find the direct link between the haemodynamic response and neuronal activity, particularly at TUoS (where I’m doing my masters!) but for the moment this is all we have. This sort of imaging is used a lot for research and checking the general function of the brain, so if you were to have had surgery on your brain, they may run one of these just to see which areas might be affected from it and how, or in research we’ve used this a lot to research cognition - which areas are affected during certain cognitive tasks (ie my MSc thesis - Cognition in schizophrenia and consanguinity). 

Diffusion Tensor Imaging (DTI)

This is my current favourite type of NI right now! DTI is beautiful, unique and revolutionary in this day and age, it’s almost like sci-fi stuff! DTI measures the rate of water diffusion along white matter tracts and with that calculates the directions and structural integrity of them to create these gorgeous white matter brain maps. They are FANTASTIC for finding structural damage in white matter - something that is making breakthroughs in research lately ie. schizophrenia, genetics and epilepsy. It measures the rate of diffusion which tells you about possible myelin/axonal damage and anisotropy, so the directions and if they are “tightly wound” or loosely put together - think of it like rope, good FA is a good strong rope, poor FA is when it starts to fray and go off in different directions - like your white matter tracts. My current research used DTI and it was honestly surreal to work with, the images are also acquired through an MRI scanner so you can actually get these images the same time you’re getting MRI’s done, functional or otherwise! 

Positron Emission Tomography (PET)

One of the “controversies” (if you could call it that) is the use of radioactive substances in PET scanning. It requires the injection of a nuclear medicine to have the metabolic processes in your brain light up like Christmas! It uses a similar functional hypothesis to BOLD fMRI, in that it is based on the assumption that higher functional areas would have higher radioactivity and that’s why it lights up in a certain way. It depends on glucose or oxygen metabolism, so high amounts of glucose/oxygen metabolism would show up red and less active areas would show up blue, perfect for showing any functional abnormalities in the overall brain. However it has incredibly poor temporal resolution and due to it’s invasive nature, MRI is chosen more often. (The pictures are gorgeous though!) 

Electroencephalography/Magnetoencephalography (EEG & MEG)

These are not “imaging” types in the stereotypical sense. They create a series of waves that you can physically see (think of the lines you get on a lie detector!). Electrodes/Tiny magnets are placed on the scalp/head in specific areas corresponding to certain brain structures. EEG picks up on electrical activity which is the basis of neuronal function, whereas MEG picks up on magnetic fields - the same property that is utilised by MRI. One of the biggest issues with EEG is that deeper structures passing through tissues get distorted, whereas MEG doesn’t because it only measures the magnetic properties. I’ve not had a lot of experience with either of these but I do know EEG is used in a lot of medical procedures to measure brain activity, from measuring seizures and sleep disorders to measuring brain activity in a coma. It’s fantastic and if you can actually figure out how to conduct and interpret results it’s an invaluable tool into looking at electrical activity. 

Grid of Id

Using a mapping technology called diffusion spectrum magnetic resonance imaging, Harvard University researcher Van Wedeen and colleagues show that the human brain may be wired more like a street map – a grid of pathways – rather than the presumed spaghetti-like tangle of neuronal connections.

The work, part of the Human Connectome Project, shows sheets of parallel neural fibers running at 90 degrees to each other, much like woven fabric, each sheet arranged at right angles to others to form a three-dimensional grid.

The Monstrous Active Galaxy NGC 1275

Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission. NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy’s core.

The reddish structure surrounding the galaxy are filaments.These filaments are cool despite being surrounded by gas that is around 55 million degrees Celsius hot. They are suspended in a magnetic field which maintains their structure and demonstrates how energy from the central black hole is transferred to the surrounding gas.

Credit: NASA, ESA and Andy Fabian (University of Cambridge, UK)

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BURMESE PYTHON EATS RAT
BURMESE PYTHON DIGESTS RAT
Noninvasive Imaging Technology Shows Animal Guts

Science is inherently cool, but gross science is even better.

Using a combination of computer tomography (CT) and magnetic resonance imaging (MRI), scientists Kasper Hansen and Henrik Lauridsen of Aarhus University in Denmark were able to visualize the entire internal organ structures and vascular systems (aka “guts”) of a Burmese Python digesting a rat.

  • A Burmese Python was scanned before ingesting a rat
  • and then at 2, 16, 24, 32, 48, 72 and 132 hours afterwards.
  • The succession of images reveals
    a gradual disappearance of the rat’s body,
  • with an overall expansion of the snake’s intestine,
  • shrinking of the gallbladder
  • and a 25 percent increase in heart volume.

(via Asylum.com)

While no pythons were harmed in making this series of images,
the same cannot be said about rats. We might take a moment to think about how rats have made great sacrifices to bring our understanding of the biological sciences to where it is today.

Effects of Anesthesia on the Fetal Brain

Exposure to anesthesia during labor and delivery results in morphological changes in the developing fetal brain. Photo credit: Bradley Peterson, MD, Institute of the Developing Mind, Children’s Hospital Los Angeles.

Recently recommended in F1000Prime, which identifies significant studies in biology and medicine based on recommendations from leadings scientists around the world, a study by researchers led by Bradley Peterson, MD of CHLA demonstrated significant effects of anesthesia used during labor and delivery on the developing fetal brain. Using high-resolution magnetic resonance imaging (MRI), Peterson and his team found infants exposed to anesthesia had areas in the frontal and occipital lobes of the brain that were larger in size compared to those who had not been exposed. The size of these areas of the brain increased with longer durations of anesthetic exposure. The effects of these differences in morphology based on anesthesia exposure are yet to be determined.

Scientists at Los Alamos National Laboratory are developing an ultra-low-field magnetic resonance imaging system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the world’s poorest regions.  

Read More - http://www.rdmag.com/news/2015/04/portable-mri-could-aid-wounded-soldiers-third-world

Imagine Erik Finding Out That You, His Young Daughter, Have Inherited His Powers

Originally posted by timestolaugh

“Slow down, Erik, what are you on about?” Charles frowned through the phone.

“Y/N has- she’s- she’s like me, Charles!” Erik sputtered. He had you in one arm, and you were squirming in an attempt to ‘do the magic’ again. You had always been very enchanted by your father when he did little magic tricks with his metallokinesis to entertain you, and you were only concerned with your joy of possessing ‘the magic’ as well.

“NO, Y/N, no, no no, we do not do that with those!” Erik said quickly, moving the silverware you had begun to float out of your sight. He pulled the phone back over to his ear to hear what Charles had to say about it. It didn’t quite matter if he had moved the dangerous utensils; you had found something else to play with.

“Just bring her to the mansion, I’ll run a few simple tests I do with the students, she’ll be fine, Erik.”

“Alright, alright, I’ll bring her up in the morning,” Erik sighed. He hung up the phone with a breath of relief, only to look down at you.

“Papa, look!” you giggled; his old, worn Magneto helmet rested loosely over your head. Memories around that helmet flooded his mind, both good and bad. He had tried to hurt in that headpiece. He had tried to kill, and he had wanted to keep that part of his past far away from you.

However, looking down at the innocence in your eyes, he felt a spark of hope. Maybe, where he had become a symbol of hate, you could be one of hope.

(For @silverwingedfox)

You’d stain your hands with
Blood so you could
Keep a hold of the sun
That always looks like it’s
Leaving you

(It’s day here but for you
I guess it’s twilight,
Can you see the moon?)

Why do you always look at
It with loathing? Is it because it
Reminds you of you?

“I wish I could understand you.”
As I said that, you looked as though you would shatter.
I’m sorry. The sun doesn’t know how to kind. If I
Was better than I am I’d have asked you
To explain.

If your gaze wasn’t so empty
Would you notice my hand
Reaching out for yours? (I wish you’d believe me
When I tell you I’m staying.)

We’re two sides of the same magnet, fused together
Yet kept apart;
We yearn for each other but we
Can never touch.

Is that why
You look up at the
Sky and say you want the sun, yet you’ll
Avert your eyes from it?
(If so, I’m the same.)

(Sometimes I get close to asking
What’s it like down your rabbit hole?
But I never do. I used to think it’s because
I was being considerate, but now I think
It’s mostly because I’m too scared to know
In case I let you know about mine.)

What a funny way to hold onto
Light; you tie it to your heart strings so
You can keep it
But you won’t look at it.
What a funny way to keep hold of
things.
Was the sun in your eyes
that irritating that you’d look away
from it so it wouldn’t be blinding?

(Still, what can I say when I look at the moon the same?)

Thinking inside the box – How our brain puts the world in order

Neuroscientists have investigated what happens when we put the world around us in order. They found out which areas of the brain help us to think inside the box.                    

Brain activity during categorisation

The world around is complex and changing constantly. To put it in order, we devise categories into which we sort new concepts. To do this we apply different strategies. A team of researchers at the Ruhr University Bochum (RUB) led by Prof. Dr. Boris Suchan, department of neuropsychology, and Prof. Dr. Onur Güntürkün, department of biopsychology, wanted to find our which areas of the brain regulate these strategies.

The results of their study using magnetic resonance imaging (MRI) show that there are indeed particular brain areas, which become active when a certain strategy of categorisation is applied.

When we categorise objects by comparing it to a prototype, the left fusiform gyrus is activated. This is an area, which is responsible for recognising abstract images. On the other hand, when we compare things to particular examples of a category, there is an activation of the left hippocampus. This field plays an important role for the storage or retrieval of memories.

Categories reduce information load

Thinking in categories or pigeonholing helps our brain in bringing order into a constantly changing world and it reduces the information load. Cognitive scientists differentiate between two main strategies which achieve this: the exemplar strategy and the prototype strategy.

When we want to find out, whether a certain animal fits into the category “bird” we would at first apply the prototype strategy and compare it to an abstract general “bird”. This prototype has the defining features of the class, like a beak, feathers or the ability to fly. But when we encounter outliers or exceptions like an emu or a penguin, this strategy may be of no use. Then we apply the exemplar strategy and compare the animal to many different known examples of the category. This helps us find the right category, even for “distant relations”.

Complex interaction

To find out where our brain is activated, when it is ordering the world, the neuroscientists in Bochum performed an MRI scan, while volunteers were completing a categorisation task. The functional imaging data showed that both strategies are triggered by different areas of the brain.

The scientists believe that there is a complex interaction between both learning patterns. “The results implicate that both strategies originate from distinct brain areas. We also observed that, during the learning process, the rhythm of activation in the two areas synchronised. This shows that both cognitive processes cannot be neatly separated,” explains Boris Suchan. Further modelling and research must now clarify this interaction.

Chemists offer enhanced 3-D look inside batteries

A team of chemists has developed a method to yield highly detailed, three-dimensional images of the insides of batteries. The technique, based on magnetic resonance imaging (MRI), offers an enhanced approach to monitor the condition of these power sources in real time.

“One particular challenge we wanted to solve was to make the measurements 3D and sufficiently fast, so that they could be done during the battery-charging cycle,” explains NYU Chemistry Professor Alexej Jerschow, the paper’s senior author. “This was made possible by using intrinsic amplification processes, which allow one to measure small features within the cell to diagnose common battery failure mechanisms. We believe these methods could become important techniques for the development of better batteries.”

The work, described in Proceedings of the National Academy of Sciences, focuses on rechargeable Lithium-ion (Li-ion) batteries, which are used in cell phones, electric cars, laptops, and many other electronics. Many see lithium metal as a promising, highly efficient electrode material, which could boost performance and reduce battery weight. However, during battery recharging it builds up deposits—or “dendrites"— that can cause performance loss and safety concerns, including fires and explosions. Therefore, monitoring the growth of dendrites is crucial to producing high-performance batteries with this material.

Read more.

Magnetic polaron imaged for the first time

Researchers at Aalto University and Lawrence Berkeley National Laboratory have demonstrated that polaron formation also occurs in a system of magnetic charges, and not just in a system of electric charges. Being able to control the transport properties of such charges could enable new devices based on magnetic rather than electric charges, for example computer memories.

Polarons are an example of emergent phenomena known to occur in condensed matter physics. For instance, an electron moving across a crystal lattice displaces the surrounding ions, together creating an effective quasi-particle, a polaron, which has an energy and mass that differs from that of a bare electron. Polarons have a profound effect on electronic transport in materials.

Artificial spin ice systems are metamaterials that consist of lithographically patterned nanomagnets in an ordered two-dimensional geometry. The individual magnetic building blocks of a spin ice lattice interact with each other via dipolar magnetic fields.

Researchers used material design as a tool to create a new artificial spin ice, the dipolar dice lattice.

‘Designing the correct two-dimensional lattice geometry made it possible to create and observe the decay of magnetic polarons in real-time,’ says postdoctoral researcher Alan Farhan from Lawrence Berkeley National Laboratory (USA).

‘We introduced the dipolar dice lattice because it offers a high degree of frustration, meaning that competing magnetic interactions cannot be satisfied simultaneously. Like all systems in nature, the dipolar dice lattice aims to relax and settle into a low-energy state. As a result, whenever magnetic charge excitations emerge over time, they tend to get screened by opposite magnetic charges from the environment,’ explains Dr. Farhan.

The researchers at Berkeley used photoemission electron microscopy, or PEEM, to make the observations. This technique images the direction of magnetization in individual nanomagnets. With the magnetic moments thermally fluctuating, the creation and decay of magnetic polarons could be imaged in real space and time. Postdoctoral researcher Charlotte Peterson and Professor Mikko Alava at Aalto University (Finland) performed simulations, which confirmed the rich thermodynamic behavior of the spin ice system.

‘The experiments also demonstrate that magnetic excitations can be engineered at will by a clever choice of lattice geometry and the size and shape of individual nanomagnets. Thus, artificial spin ice is a prime example of a designer material. Instead of accepting what nature offers, it is now possible to assemble new materials from known building blocks with purposefully designed functionalities,’ says Professor Sebastiaan van Dijken from Aalto University.

‘This concept, which goes well beyond magnetic metamaterials, is only just emerging and will dramatically shape the frontier of materials research in the next decade,’ adds Professor van Dijken.

Research article:
Alan Farhan, Andreas Scholl, Charlotte F. Petersen, Luca Anghinolfi, Clemens Wuth, Scott Dhuey, Rajesh V. Chopdekar, Paula Mellado, Mikko J. Alava & Sebastiaan van Dijken.
Thermodynamics of emergent magnetic charge screening in artificial spin ice.
Nature Communications 7 (2016). http://dx.doi.org/10.1038/ncomms12635