Tag: brains

Scientists Discover A New Type Of Brain Cell In Humans

An international team of 34 scientists has identified a new type of brain cell in humans not found in other well-studied species.

The discovery of “Rosehip” neurons, published today in the journal Nature Neuroscience, raises a number of questions: How does it influence human behavior and experience?

How does it differentiate us from other species? Can it be found in primates and other cognitively advanced species?

But there is one issue this discovery highlights immediately: there’s a neuron in human brains that is missing from the brains of mice and other animals used to model human brains in experiments.

Does this mean current animal models yield distorted results? “If we want to understand how the human brain works, we need to study humans or closely related species,” says Trygve Bakken, co-author of the paper and a neuroscientist at the Allen Institute for Brain Science.




The flow of info

Rosehip neurons are inhibitory neurons that form synapses with pyramidal neurons, the primary excitatory neurons in the prefrontal cortex.

We all have inhibitory neurons and excitatory neurons,” says Bakken, “but this particular type of inhibitory neuron is what’s new in this study. It’s special based on its shape and its connections and also the genes that it expresses.

When a traffic signal turns red it helps controls the flow of traffic. Similarly, inhibitory neurons help control the flow of electrochemical information.

The type of information rosehip neurons control, and why they appear particular to humans, is yet to be discovered. “It has these really discrete connections with [pyramidal] neurons,” says Bakken.

It has the potential to sort of manipulate the circuit in a really targeted way, but how that influences behavior will have to come in later work.”

Found in the neocortex of human brains

The researchers identified rosehip neurons by looking at brain samples from two males who died in their 50’s and donated their bodies to science.

The brain slabs were tissue from the neocortex, a most recent evolutionary development inside our skulls responsible for higher-order thinking.

The neocortex, the outermost layer of cells, is greatly expanded in humans–about a thousandfold compared to mice,” says Bakken.

From neurological studies, if you have a stroke in your neocortex for example, it really impacts your ability to do these sorts of high-order cognitive processing.

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The New CRISPR-Gold Technique Reduces Behavioral Autism Symptoms In Mice

A remarkable new study has successfully used the CRISPR-Cas9 gene editing technique to edit a specific gene in mice engineered to have fragile X syndrome (FXS), a single-gene disorder often related to autism.

The single gene edit in the live mice resulted in significant improvements in repetitive and obsessive behaviors, making this the first time gene editing has been used to effectively target behavioral symptoms related to autism spectrum disorder (ASD).

FXS is a genetic disorder associated with intellectual disability, seizures and exaggerated repetitive behavior.

Previous studies have shown that the repetitive behaviors associated with FXS are related to a specific excitatory receptor in the brain that, when dysregulated, causes exaggerated signaling between cells.




The CRISPR technique homes in on the gene that controls that excitatory receptor, the metabotropic glutamate receptor 5 (mGluR5), and essentially disables it, dampening the excessive signaling the corresponds with repetitive behaviors.

In mice treated with the new system, obsessive digging behavior was reduced by 30 percent and repetitive leaping actions dropped by 70 percent.

An even more fascinating element of this new research was the novel CRISPR-Cas9 delivery method, pioneered by a team at the University of California, Berkeley.

The most commonly used gene delivery technique for CRISPR harnesses the power of viruses to ferry the Cas9 enzyme to a targeted cell.

But viral gene delivery has its limitations. As well as battling the potential for a person’s immune system to develop antibodies against the virus, this delivery system makes it difficult to control how much Cas9 is ultimately delivered.

The effectiveness of this CRISPR-Gold system in accurately editing specific genes in brain cells could in the future be potentially applied to a broad assortment of different genetic diseases, as well as targeting other social interaction symptoms associated with ASD.

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Honey Bees Can Understand Nothing

Zero, zilch, nothing, is a pretty hard concept to understand. Children generally can’t grasp it until kindergarten. And it’s a concept that may not be innate but rather learned through culture and education.

Throughout human history, civilizations have had varying representations for it. Yet our closest animal relative, the chimpanzee, can understand it.

And now researchers in Australia writing in the journal Science say the humble honey bee can be taught to understand that zero is less than one.

The result is kind of astounding, considering how tiny bee brains are. Humans have around 100 billion neurons. The bee brain? Fewer than 1 million.

The findings suggest that the ability to fathom zero may be more widespread than previously thought in the animal kingdom — something that evolved long ago and in more branches of life.




It’s also possible that in deconstructing how the bees compute numbers, we could make better, more efficient computers one day.

Our computers are electricity-guzzling machines. The bee, however, “is doing fairly high-level cognitive tasks with a tiny drop of nectar,” says Adrian Dyer, a Royal Melbourne Institute of Technology researcher and co-author on the study.

Their brains are probably processing information in a very clever [i.e., efficient] way.”

But before we can deconstruct the bee brain, we need to know that it can do the complex math in the first place.

How to teach a bee the concept of zero

Bees are fantastic learners. They spend hours foraging for nectar in among flowers, can remember where the juiciest flowers are, and even have a form of communication to inform their hive mates of where food is to be found.

Researchers train bees like they train many animals: with food. “You have a drop of sucrose associated with a color or a shape, and they will learn to reliably go back to” that color or shape, Dyer explains.

With this simple process, you can start teaching bees rules. In this case, the researchers wanted to teach 10 bees the basic rules of arithmetic.

So they put out a series of sheets of paper that had differing numbers of objects printed on them. Using sugar as a reward, the researchers taught the bees to always fly to the sheet that had the fewest objects printed on it.

Once the bees learned this rule, they could reliably figure out that two shapes are less than four shapes, that one shape is smaller than three. And they’d keep doing this even when a sugary reward was not waiting for them.

And then came the challenge: What happens when a sheet with no objects at all was presented to the bees? Would they understand that a blank sheet — which represented the concept of zero in this experiment — was less than three, less than one?

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No, there Hasn’t Been A Human ‘Head Transplant’, And There May Never Be

Neurosurgeon Sergio Canavero is in the news again, claiming to have performed the first successful human head transplant. But even cursory analysis reveals that he hasn’t.

And scientific logic suggests he never will.

In February 2015, Sergio Canavero appeared in this very publication claiming a live human head will be successfully transplanted onto a donor human body within two years.

He’s popped up in the media a lot since then, but two years and nine months later, how are things looking?

Well, he’s only gone and done it! As we can see in this Telegraph story from today, the world’s first human head transplant has been successfully carried out.

Guess all those more timid neurobods who said it couldn’t be done are feeling pretty foolish right now, eh?

Well, not quite. Because if you look past the triumphant and shocking headlines, the truth of the matter becomes very clear, very quickly.




These “successful” procedures are anything but

Many of Canavero’s previous appearances in the media have been accompanied by claims of successful head transplant procedures.

But, how are we defining “successful” here? Canavero’s definition seems to be extremely “generous” at best.

For instance, he recently claimed to have “successfully” performed a head transplant on a monkey. But did he?

While the monkey head did apparently survive the procedure, it never regained consciousness, it was only kept alive for 20 hours for “ethical reasons” and there was no attempt made at connecting the spinal cord.

So even if the monkey had survived long-term it would have been paralysed for life. So, it was a successful procedure.

If you consider paralysis, lack of consciousness and a lifespan of less than a day as indicators of “success”.

There was also his “successful” rat head transplant, which involved grafting a severed rat head onto a different rat, a living one that still had its head.

Exactly how this counts as a “transplant” is anyone’s guess. It’s adding a (functionally useless) appendage onto an otherwise healthy subject.

And this recent successful human head transplant? It was on corpses!

Call me a perfectionist if you must, but I genuinely think that any surgical procedure where the patients or subjects die before it even starts is really stretching the definition of “success” to breaking point.

Maybe the procedure did make a good show of “attaching” the nerves and blood vessels on the broad scale, but, so what?

That’s just the start of what’s required for a working bodily system. There’s still a way to go.

You can weld two halves of different cars together and call it a success if you like, but if the moment you turn the key in the ignition the whole thing explodes, most would be hard pressed to back you up on your brilliance.

Perhaps the techniques used to preserve the heads and attach them have some scientific value, but it’s still a far cry from the idea of someone wandering around with a fully functional body that isn’t the one they were born with.

Canavero seems to have a habit of claiming barnstorming triumph based on negligible achievements, or even after making things much worse. He seems to be the neurosurgical equivalent of the UK Brexit negotiating team.

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Each Time You Recall An Event, Your Brain Distorts It

Remember the telephone game where people take turns whispering a message into the ear of the next person in line?

By the time the last person speaks it out loud, the message has radically changed. It’s been altered with each retelling.

Turns out your memory is a lot like the telephone game, according to a new Northwestern Medicine study.

Every time you remember an event from the past, your brain networks change in ways that can alter the later recall of the event.

Thus, the next time you remember it, you might recall not the original event but what you remembered the previous time. The Northwestern study is the first to show this.

A memory is not simply an image produced by time traveling back to the original event it can be an image that is somewhat distorted because of the prior times you remembered it,” said Donna Bridge, a postdoctoral fellow at Northwestern University Feinberg School of Medicine and lead author of the paper on the study recently published in the Journal of Neuroscience.




Your memory of an event can grow less precise even to the point of being totally false with each retrieval.”

Maybe a witness remembers something fairly accurately the first time because his memories aren’t that distorted,” she said. “After that it keeps going downhill.”

The published study reports on Bridge’s work with 12 participants, but she has run several variations of the study with a total of 70 people.

Every single person has shown this effect,” she said. “It’s really huge.

The reason for the distortion, Bridge said, is the fact that human memories are always adapting.

Memories aren’t static,” she noted.

If you remember something in the context of a new environment and time, or if you are even in a different mood, your memories might integrate the new information.

For the study, people were asked to recall the location of objects on a grid in three sessions over three consecutive days.

On the first day during a two-hour session, participants learned a series of 180 unique object-location associations on a computer screen.

The next day in session two, participants were given a recall test in which they viewed a subset of those objects individually in a central location on the grid and were asked to move them to their original location.

Then the following day in session three, participants returned for a final recall test.

The results showed improved recall accuracy on the final test for objects that were tested on day two compared to those not tested on day two.

However, people never recalled exactly the right location.

Most importantly, in session three they tended to place the object closer to the incorrect location they recalled during day two rather than the correct location from day one.

Our findings show that incorrect recollection of the object’s location on day two influenced how people remembered the object’s location on day three,” Bridge explained.

Retrieving the memory didn’t simply reinforce the original association. Rather, it altered memory storage to reinforce the location that was recalled at session two.

The results revealed a particular electrical signal when people were recalling an object location during session two.

This signal was greater when the next day the object was placed close to that location recalled during session two.

When the electrical signal was weaker, recall of the object location was likely to be less distorted.

The research was supported by National Science Foundation grant BCS1025697 and National Institute of Neurological Disorders and Stroke of the National Institutes of Health grant T32 NS047987.

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