Author Archives: Samantha Adler

About Samantha Adler

Sam is a neuroscience PhD candidate at the University of Texas Health Science Center at San Antonio. She hopes that by writing and editing for ZME Science she can contribute to making science more accessible to the general public.

Music can be used to estimate political ideology to an “accuracy of 70%”, researchers say

Do you like Pharrell’s “Happy”? Then you’re probably a conservative.

If you’ve ever tried to argue with a stranger on the Internet about politics (or with your family at Thanksgiving dinner), you’re well aware that it’s a recipe for disaster: political ideology is often so deeply rooted that it feels hard-wired into our DNA. Political ideology strongly influences our views on things like economics and social policies, but could it also have far-reaching influences on things we aren’t even aware of? The Fox Lab at New York University believes the answer is yes.

Their theory?

“Ideology fundamentally alters how we perceive a neutral stimulus, such as music,” said Caroline Myers, who presented her research at the 2018 Society for Neuroscience Meeting.

To examine the influence of political ideology on musical preference, participants self-reported their political ideology as liberal, conservative, or center, and then listened to clips from 192 songs. For each song clip, they would rate how familiar they were with the song and then how much they liked or disliked it. These songs included the top 2 songs each year from the Billboard Top 40, iconic songs across certain genres, and a selection of more obscure music. Participants additionally ranked how often they believed they listened to certain genres of music — which led to some surprising findings.

For example, 60% of individuals who identified as liberals said that they listen to R&B music, and yet they weren’t any more familiar with these songs than any other group — and they actually liked R&B songs less than their conservative counterparts. Liberals also stated they listen to jazz but were not any more familiar with jazz music than the other groups.

They also looked at individual song preference across the various ideologies. Some did not showcase any major differences, with classical music being the least divisive of all the musical genres. The most polarizing song, however, was “Happy” by Pharrell Williams. Conservatives love it, while liberals hate it. And there’s actually evidence of this in the real world — just two weeks ago, Pharrell issued President Donald Trump a cease and desist order for using the song at one of his rallies.

While we can use this information to create a kick-ass playlist for our like-minded friends, is there any evidence that we can guess an individual’s political ideology purely based on musical taste? Surprisingly, the answer is yes.

“We were able to estimate individual’s ideological leanings to an accuracy of 70%,” said Myers.

Myers is currently working on addressing the limitations of her study such as the limited number of conservative participants due to heavy on-campus recruiting for the study. However, the results are still striking, and quite concerning, from a personal data standpoint. It goes to show that, even if we’re not actively posting personal details on social media, companies may still have other means to gain insight into our personal preferences – and we might not even be aware of it.

The Wonderful World of Bacteriophages

We all know that the primary types of infection are viral and bacterial, but what about a virus that infects bacteria? Enter the bacteriophage, a virus that infects bacteria.

Read on to learn all about bacteriophages, how they infect their bacterial hosts, and how they might be used to solve the problem of antibiotic resistance in the near future.

A head-tail bacteriophage. Credit: Adenosine on WIkimedia Commons

What Does a Bacteriophage Look Like?

All bacteriophages infect bacteria, but the way they’re structured can be quite different. First of all, their genomes (their genetic material) can be made up of either DNA or RNA. Their genome can also vary in size. The smallest known bacteriophage genome actually contains only twenty genes, but they can contain hundreds. That means that they can function quite simply or their functioning can be incredibly complex.

The most well-studied bacteriophages look like the image above, called the head-tail phage. But some lack a tail, while others are shaped like a long strand (called filamentous phages). Bacteriophages have adapted over time to take on the shape best suited to infect their host bacteria of choice.

In fact, bacteriophages are so diverse that there’s an entire field to exploring their diversity. Metagenomics is the study of genetic material obtained from environmental samples, letting scientists examine bacteriophages that have some environmental significance.

How Does a Bacteriophage Infect Its Host?

Just like viruses, bacteriophages must infect a host so they can carry on their lineage. Now, bacteriophages have two possible ways to infect their host. They can either undergo what is called the lytic cycle, which ultimately kills the host bacteria, or the lysogenic cycle, which does not kill the host bacteria. Some bacteriophages, like lambda bacteriophages, can even switch between the two.

A visual depiction of the first two steps of host infection by a bacteriophage. Credit: Graham Colm on Wikimedia Commons

The first two steps are the same: the bacteriophage’s tail attaches to the surface of the bacterium, and the phage then injects its genome inside. In the lytic cycle, the genome copies itself once inside the bacterium. The DNA contains instructions for the bacteria to create proteins required to form more bacteriophages, called capsids. By hijacking the bacteria’s internal machinery, it creates many new bacteriophages.

Once enough have been made, these new bacteriophages poke holes in the membrane. Water rushes in until the bacterium expands and bursts, allowing these new bacteriophages to be free. Now they can go out and repeat the process. It’s called the lytic cycle because the cell bursting open is a process known as lysis.

It’s easy to see the pros and cons of this process. One bacteriophage can use a host bacterium to create tons of copies. But this process also kills its host, meaning that if a new suitable bacterium is not located, the new bacteriophages will soon die.

To overcome this, some bacteriophages have adapted by using the lysogenic cycle. Once the bacteriophage’s genome is inside the bacteria, it integrates into the host bacterium’s genome in a process called integration, creating what is called a prophage. This contains the information required to undergo the replication cycle of the bacteriophage. And this change is permanent: once the bacterium divides, the offspring will also have the prophage integrated into their genome.

This process keeps the bacteriophage’s genome safe until it’s time for replication. When the conditions are right, the prophage will exit the bacterium’s genome. Once the prophage exits, the lytic cycle begins in order to release a new set of bacteriophages.

A visual depiction of the two cycles of bacteriophage infection. Credit: Suly12 on Wikimedia Commons

Bacteriophages in Medicine

It may surprise you to learn that bacteriophages might be the answer to antibiotic resistance. In fact, long before we learned how to make and produce antibiotics, we used bacteriophages to treat bacterial infections. And this makes a lot of sense: bacteriophages target and kill bacteria via the lytic cycle, and they don’t target human cells.

So, why did we stop using them? Well, this treatment was started in the Soviet Union, so the Cold War almost certainly played some role in our reluctance to adopt them. Additionally, a lot of the research published on the subject was in Russian, so the international community wasn’t very familiar with these publications. Finally, antibiotics were simply easier to make, store, and administer.

Russia and several Eastern European countries still use these methods today. And while some may scoff at the idea of using medical techniques derived almost 100 years ago, these just might be the answer to our antibiotic woes. And a recent study presented at ASM Microbe shows that this idea is starting to catch on in America, too.

While bacteria can adapt to resist certain bacteriophages as well, researchers believe that resistance to a bacteriophage is actually a temporary trait. This means that any resistance formed will not force genetic divergence and therefore will not be relevant after a resting period of time, nor will it generalize to all types of phages.

Bacteriophages are all around us. In fact, there are estimated to be ten million trillion trillion. That’s more than every other organism on earth (including bacteria) put together. It just goes to show that when looking for the next big thing in medicine, maybe all we need to do is look at the diverse world around us.

We’re all familiar with DNA, but what about its lesser-known brother, RNA? Close in concept, but very different in purpose, these two types of nucleic acid areessential to our biology. So, what is RNA, or, Ribonucleic acid?

A visual representation of RNA coding. Credit: Thomas Splettstoesser on Wikimedia Commons

RNA’s Purpose

While DNA encodes your genes, RNA is important for how those genes get expressed. During the process of transcription, RNA is created by reading DNA with something called RNA polymerase.

The most important subtype of RNA is mRNA, which stands for messenger RNA. This type of mRNA carries the information from the DNA and goes over to ribosomes in order to create proteins. And proteins are the molecules that actually go forth and make changes in the body.

The central dogma of molecular biology. Credit: Madprime on Wikimedia Commons.

So, it’s sort of like DNA is a booklet containing all possible instructions for how to make things in the body, RNA are copies of only the relevant information for what the body needs right now, and proteins are the workers that go out and make it happen. This is known as the central dogma of molecular biology.

RNA vs DNA

A visual representation of the primary differences between RNA and DNA. Credit: Verwendete Bilder on Wikimedia Commons.

RNA and DNA have a surprising number of similarities. And it makes sense: RNA is literally copying itself from that main template.

For example, RNA and DNA both are made up of four nucleotide building blocks. DNA is made up of G, T, A, and C. RNA is similar, but substitutes the T (thymine) for U (uracil). Uracil actually looks just like thymine but lacks one methyl (CH3) group that thymine has.

DNA is double-stranded, but RNA is just one strand (it can form double strands but this isn’t RNA’s normal state). It’s easier to stay this way because it’s a much shorter strand of molecules. Why? In its single-stranded form, it’s genetically cheaper to make (half the material) while still containing all of the information (after all, if one always pairs with the other then you know exactly what that other strand had to be). Also, it’s easier to read. We actually have to unzip the DNA helix in places in order to access the code within, while RNA already comes in a form that’s open and easy to read.

Finally, they have different backbones. DNA is held together by deoxyribose, the sugar-phosphate backbone holding all of those nucleotides in order. RNA’s backbone is made up of ribose. Ribose is a lot like deoxyribose but has an additional hydroxyl (OH) group. So, deoxyribose is just de-oxygenated ribose, because it doesn’t have that oxygen.

Special Types of RNA

When most people think of RNA, they think of mRNA. But there are several additional subtypes of RNA that each have special functions.

The process of creating mRNA wouldn’t be possible without other forms of RNA. Transfer RNA (tRNA) is required to bring amino acids to the ribosome. In the ribosome, ribosomal RNA (rRNA) links together amino acids so they can create proteins. Taken together, tRNA, rRNA, and mRNA are referred to as coding RNAs because they all work together to encode proteins.

A visual depiction of translation machinery. Credit: NHS HEE Genomics Education Programme on Flickr.

Most noncoding RNA performs regulatory functions. The most popular of this category are microRNA (called miRNA or miR). These miRNAs can pair with single-stranded mRNA. When it does so, these mRNAs are tagged to be degraded. Therefore, miRNA can tag mRNA and shut down protein translation. So miRNA is usually used to control the amount of protein being produced from mRNA.

There’s also a very similar subtype called small interfering RNA (siRNA) which tags RNA for degradation right after transcription. It can be used to prevent any protein from being created. In addition, siRNA is often artificially used in labs to prevent certain proteins from being created and then see how this affects other biological processes.

siRNA mechanism of action. Credit: Singh135 on Wikimedia Commons.

Enhancer RNA (eRNA) was only first discovered in 2010. They are transcribed from “enhancer” regions of DNA – regulatory sites known to enhance gene expression. These eRNAs are also used to up-regulate the amount of mRNA produced from that DNA segment.

Small nucleolar RNA, called snoRNA, helps chemically modify other groups of RNA. They may help add either a methyl group (CH3), a process called methylation. Or they can turn one of the nucleotides into a uridine, a process called pseudouridylation.

Finally, there are long non-coding RNAs (lncRNAs). They are thought to silence long stretches of DNA. They also are thought to be involved in regulating stem cell division very early on in life.

What is RNA? Now You Know!

Now you’ve learned all about the mysteries of RNA. While not as widely known as DNA and not as flashy as protein function, it still remains one of the three cores of molecular biology. Life couldn’t exist without it. In fact, RNA is often thought to potentially be responsible for forming all life.

Brain-lentine: Valentine’s gifts for your brainy loved one

Are you looking for a gift to get the neuroscientist in your life? Try one of these gifts to show your partner you are just as brainy as they are.

Brain Specimen Coasters

These brain specimen coasters will make your significant other the envy of all of his or her coworkers! And when they’re stacked up, they look like a 3D brain — I personally know a lot of people who have gotten these as gifts, and they’ve all loved it.

Appeal to Their Creative Side with a Neuroscience Coloring Book

Adult coloring books are all the rage, but what if you could color something you love and learn something, too? These two coloring books let you color the brain and learn a bit about its structure in the process.

There’s also more than one option here — here’s another really cool alternative!

Or Buy Her Some Brain Art

 

Coloring is definitely not for everyone, and why go through the extra effort when you can just buy an amazing piece of brainy art? These beautiful brain-themed art pieces will appeal to her right brain (just kidding, that’s not actually a thing).

Here’s another option (buy on Amazon):

Or maybe you’d rather get her some beautiful neuron-themed art pieces?

Brainy clothes

A Neuroscience-Themed Wardrobe? Yes, please! It’s cold in February, so what about this beautiful scarf:

Or, get them something they can show off to all of their coworkers. Check out this whimsical shirt:

Jewelry is Always Nice

And, of course if you want to go for the safe bet, get them some jewelry – but make it brain-themed!

Try neurons:

Or this bracelet:

Or if all else fails, a brain necklace is always a safe bet. Right?

These gifts will definitely make that brainy guy or girl in your life release some oxytocin and help your pair-bonding! Have you made up your mind yet?

Disclaimer: Purchasing these products may earn ZME Science a commission. This helps support our team at no additional cost to you. We will never advertise products if we don’t think they’re good. If something is here, it’s because we like it — period.

Why do people self-harm? New study offers surprising answers

If you’ve seen HBO’s newest miniseries, Sharp Objects, you’re well familiar with what doctors call NSSI: non-suicidal self-injury. NSSI is a serious mental health condition, but despite years of research, we’re still not quite sure why individuals engage in this type of behavior. A new study performed at St. Edward’s University in Austin, Texas, sought the answer to this question by drawing on existing theories in the literature.


Previous studies have shown that individuals who exhibit NSSI have low levels of β-endorphin, which is produced to mediate stress-induced analgesia (the inability to feel pain) — and high ratings of clinical dissociation, which is a feeling of disconnection with oneself and one’s surroundings. The researchers hypothesized that NSSI individuals are attempting to restore these imbalances using self-harm. To test their hypothesis, researchers recruited participants from the university. Using saliva samples and surveys, they assessed β-endorphin levels and psychological state before and after a procedure called the cold-pressor test.

[panel style=”panel-info” title=”Cold-Pressor Test” footer=””]During the cold-pressor test, an individual immerses his or her hand in a bucket of ice water. Researchers then note how long it takes the individual to feel pain (their pain threshold) and how long until the pain is unbearable (pain tolerance), at which point the test ends.
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They discovered that non-suicidal self-injurers have lower levels of arousal than people without these tendencies (the control group). After the pain challenge, their arousal levels matched the baseline of the control group — in other words, experiencing pain was able to correct their low levels of arousal. The pain challenge also decreased symptoms of dissociation. However, these changes weren’t exclusive to the NSSI group: the control group also experienced an increase in arousal and a decrease in dissociative symptoms after the cold-pressor test.

Next, the researchers sorted the NSSI group by symptom severity. They found that the more severe the individual’s NSSI symptoms, the stronger their dissociative symptoms were. However, only the most severe cases experienced a reduction in these symptoms after the pain challenge. Another interesting finding is that the NSSI individuals with moderate symptom severity actually had higher levels of β-endorphins (both before and after the pain challenge). This wasn’t seen in those with low or high symptom severity.

However, perhaps the most surprising part of the study was the high percentage of NSSI participants. 

“The literature states that there’s a 5% prevalence of NSSI in the general population, and we found this in 17 out of 65 participants, which is way above what we would expect, even when taking into consideration that university students tend to have a higher NSSI rate than the general population,” said Haley Rhodes, who presented the research at the 2018 Society for Neuroscience Meeting.

Rhodes admits that a bigger sample size is necessary before we can draw full conclusions from the data, but it’s intriguing that there seems to be a minor psychological benefit to the pain — though it most definitely doesn’t warrant any self-harming practices.

Understanding the imbalances in individuals that partake in NSSI might help us find a way to provide for their psychological needs, and allow them to get the same benefits without needing to resort to self-injury.

 

 

Using only light, scientists can manipulate memory — it’s called optogenetics

It may sound like science fiction, but neuroscientists are currently able to manipulate the activity of specific neurons in the brain — with light alone.

Image Credits: Geralt / Pixabay

Using certain wavelengths of light, researchers can turn neurons on and off at will, thanks to a technique called optogenetics. Even better —  they’re already able to use this technique to manipulate memory in animals. Let’s dive into how this technique works and see how optogenetics is used to manipulate memory – and what it could mean for the rest of us.

What is Optogenetics?

Erasing memories with a flash of light à la Men in Black might not be that far off — and we have algae to thank for this.

It’s been known for quite a while that unicellular algae are able to control ion flow across their membrane by using light. That’s particularly relevant for neuronal activity, which is also determined by the flow of positive and negative charge. If the inside of the neuron becomes sufficiently positively charged, it “activates” the neuron. Conversely, if the inside is negatively charged, the neuron will be unable to activate. So by applying the algae’s technique, neurons are able to be switched on and off using nothing more than light.

However, the mechanism for this process wasn’t well understood until 2002, when researchers identified the key protein that makes this work: channelrhodopsin. When exposed to blue light, channelrhodopsin allows positive charge to enter the neuron, leading to the cell’s “activation”.

It only took three years for scientists at Stanford to successfully insert this newly-identified channel into neuronal cells and control their activity — so by 2005, the earliest form of optogenetics was already available. It’s stunning how quickly things have developed, but it just goes to show that scientific discoveries can have far-reaching, unpredictable consequences.

But this is only the beginning.

Getting these channels into animals is no easy feat because they need to be expressed in their DNA. This is done either by breeding animals that are engineered to express the protein or by introducing a virus that can change DNA in a region of interest — and this is where it gets really interesting.

Image credit: qimono / Pixabay

 

Some viruses can change the DNA of cells they’re injected into. In this case, researchers inject the virus into their brain region of interest and, after 1-2 months, the protein will be fully expressed. The most amazing aspect of the technique is its simplicity. When it’s time to manipulate brain activity, researchers simply shine a laser light onto the area of the brain they want to manipulate. We can even do this in fully awake, functioning animals – the light itself doesn’t bother them in any way.

What can we use this for?

Since 2005, optogenetics has grown and developed, no longer being limited to rhodopsin channels — but the basic principles remain the same. Researchers have access to several photoactivatable proteins and channels, most of which have been developed form a variety of light-sensitive plants and bacteria.

For example, Dr. Klaus Hahn at UNC Chapel Hill developed a photoactivatable protein, called Rac1, that uses a light-sensitive protein domain found in a plant that keeps the protein non-functional until it is exposed to light. Dr. Haruo Kasai at the University of Tokyo took things one step further, modifying the protein so that it works in the brain.

Dr. Kasai and colleagues found that prolonged activation of the protein Rac1 shrinks synaptic spines — neuronal protrusions which help transmit electrical signals to the neuron’s cell body. It’s speculated that the formation or the enlargement of spines is essential for long-term memory storage.

In a groundbreaking Nature paper, Dr. Kasai modified this protein so it would only be expressed in spines that had recently created or modified in size — the idea was to target newly formed memories. Kasai’s team trained mice expressing this protein to improve performance on a task. After subsequently shining blue light onto their brains, the mice behaved as though they had never trained in the first place.

You might be wondering why we would even want to develop technology that erases memory. Well, one potential application is to erase “bad” memories — such as trauma experienced in patients with PTSD. Work on this has already started.

[panel style=”panel-success” title=”Fear conditioning” footer=””]In rodents, fear is tested using a technique called fear conditioning. Typically, this is done by making the rodent associate an unpleasant event, a foot shock, with a particular cue, such as a tone. However, in work done by Dr. Roberto Malinow at UC San Diego, they skipped the “middleman” and instead stimulated a pathway from the auditory cortex (used for processing sounds) to the amygdala (used to create a fear memory) using channelrhodopsin to “mimic” a tone-shock pairing. After showing the rats had developed fear, the researchers used a process called long-term depression to weaken this connection and found that when they tested animals again, they behaved like they had never learned the fear in the first place.

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A reminder

Of course, it makes much more sense to think about the opposite — bringing back lost memories. Here, optogenetics shines once again.

Just last year, Dr. Christine Denny and her team at Columbia University demonstrated that they could bring back memories in a mouse model suffering from Alzheimer’s disease. They were able to do this by using mice that, through genetic programming, are able to permanently “tag” neurons under certain conditions. Some researchers believe that the network of neurons connected with one another are what actually stores long-term memories — and activating all of these neurons at the same time was able to “remind” the mice of that memory. In other words, optogenetics can “tag” this group of neurons, activating it later to reinstate those connections and return the memory.

Image credits: Stefanie Kaech & Gary Banker, OHSU / ZEISS Microscopy

To sum things up, scientists are using the new tool of optogenetics, and it’s impressive how far they’ve been able to come in such a short time. Optogenetics is making great strides in the field of memory research, and it shows a great deal of potential. Although the creation and destruction of memories may sound dangerous, it also has great therapeutic potential for a wide variety of neuropsychiatric diseases. Who knows — perhaps one day we’ll just go to the doctor to receive our “laser treatments” to combat the memory loss associated with old age.

Articles:

Wu, Y. I., et al. (2009). “A genetically encoded photoactivatable Rac controls the motility of living cells.” Nature 461(7260): 104-108.

Hayashi-Takagi, A., et al. (2015). “Labelling and optical erasure of synaptic memory traces in the motor cortex.” Nature 525(7569): 333-338.

Nabavi, S., et al. (2014). “Engineering a memory with LTD and LTP.” Nature 511(7509): 348-352.

Perusini, J. N., et al. (2017). “Optogenetic stimulation of dentate gyrus engrams restores memory in Alzheimer’s disease mice.” Hippocampus 27(10): 1110-1122.