Tag Archives: neuron

Chinese woman completely lacks a cerebellum

A Chinese woman has shocked doctors when it was revealed that she reached 24 years without having a cerebellum. It is not the first time a person was living fine without having a cerebellum, but she entered an extremely select group, which only features 9 other people.

A hole at the back (top) where the cerebellum should be (Top image: Feng Yu et al.; Bottom image: Zephyr/Science Photo Library )

The woman checked in at the Chinese PLA General Hospital of Jinan Military Area Command in Shandong Province, reporting a severe case of dizziness and nausea. She told doctors that she always had a problem walking straight, and she only started talking at the age of 6, but nobody was expecting this. They did a CAT scan and quickly identified the problem: her entire cerebellum was missing, being filled with cerebrospinal fluid.

The cerebellum (Latin for “little brain”) is a region of the brain that plays a crucial role in the human body. In addition to its direct role in motor control, the cerebellum also is necessary for several types of motor learning, most notably learning to adjust to changes in sensorimotor relationships – your body’s sensors. It’s different structurally from the rest of the brain, consisting of smaller and more compact folds of tissue. It amounts for only 10 percent of the brain’s volume, but has almost half of all the brain’s neurons.

The condition is so rare that there is no clear description or theory of why it happens.

“These rare cases are interesting to understand how the brain circuitry works and compensates for missing parts,” says Mario Manto, who researches cerebellar disorders at the Free University of Brussels in Belgium. The patient’s doctors suggest that normal cerebellar function may have been taken over by the cortex – brain scans should reveal the answer.

 

 

Scientists successfully implant new neurons into the brain

Scientists from the University of Luxembourg have for the first time successfully grafted neurons reprogrammed from skin cells into the brains of mice, obtaining long term stability; six months after the procedure, the neurons were fully integrated into the brain. This procedure raises new hopes for replacing sick neurons with new ones, especially for patients suffering from degenerative diseases such as Parkinson’s.

The group was led by Prof. Dr. Jens Schwamborn and Kathrin Hemmer and is focused around finding solutions for people suffering from currently untreatable degenerative diseases. Their answer was to simply replace the old, sick neurons, with new ones, and see if it works. So far, their technique has proven successful in mice, but even with such promising results, there’s still a long way before human treatment can be discussed.

“Successes in human therapy are still a long way off, but I am sure successful cell replacement therapies will exist in future. Our research results have taken us a step further in this direction,” declares stem cell researcher Prof. Schwamborn, who heads a group of 15 scientists at LCSB.

In order to do this, they reprogrammed skin cells to act as neurons, creating stable nerve tissue in the brain. Their technique of using cells from the same mouse (skin cells) drastically improves the compatibility of the implanted cells. Even in the initial results, 6 months after the implantation, mice showed to signs of rejection or incompatibility. Furthermore, the neurons exhibited normal activity and were connected to the original brain cells via newly formed synapses, the contact points between nerve cells.

Again, these are just the initial results, but scientists are confident in further developing the technique and implementing it in humans – something which they believe will happen relatively soon. In the future, implanted neurons could produce dopamine and/or transport it in the brain. This is the next step in their research.

“Building upon the current insights, we will now be looking specifically at the type of neurons that die off in the brain of Parkinson’s patients – namely the dopamine-producing neurons,” Schwamborn reports.

Read the full paper here.

Scientific Reference: Hemmer K., Zhang M., van Wüllen, T., Sakalem M., Tapia N., Baumuratov A., Kaltschmidt C., KaltschmidtB, Schöler H. R., Zhang W., Schwamborn J. C. (2014) Induced neural stem cells achieve long-term survival and functional integration in the adult mouse brain. Stem Cell Reports, accepted, DOI: http://dx.doi.org/10.1016/j.stemcr.2014.06.017

 

 

Scientists erase memory (and then reactivate it) in rats

Researchers have erased and then reactivated memories in rats, profoundly impacting the animals’ reaction to past events. This is the first study ever to demonstrate the ability to selectively erase and then reactivate a memory by stimulating nerves in the brain at frequencies that strengthen synapses, the connection between neurons.

The Eternal Sunshine of the Spotless Mind

Quite possibly Jim Carrey’s best movie (and this says a lot), The Eternal Sunshine of the Spotless Mind deals with erasing memories and them bringing them back, and explores the very nature of memory – and love. I won’t spoil anything if you haven’t seen it yet, but you really should look at it.

I didn’t think we’d be dealing with anything like this anytime soon – and yet here we are. In this research, published on the 1st of June, scientists have erased, and then reactivated memories in rats.

“We can form a memory, erase that memory and we can reactivate it, at will, by applying a stimulus that selectively strengthens or weakens synaptic connections,” said Roberto Malinow, MD, PhD, professor of neurosciences and senior author of the study.

First of all, they genetically modified rats in order to make some of their optical nerves sensible to light. They then stimulated the nerves, then simultaneously delivered an electrical shock to the animal’s foot. This created a conditional reflex, and the animals soon learned to associate the optical nerve stimulation with pain; whenever they would experience this, they would feel fear.

They then analyzed these nerves, and found indications of synaptic strengthening.

In the next stage of the experiment, they stimulated the same nerves, but this time with a memory-erasing, low-frequency train of optical pulses. After this, no matter how they stimulated the nerves, the rats didn’t respond with fear, and showed no indication of remembering the initial association.

Recreating Memories

But this wasn’t all. In what is maybe the study’s most startling discovery, they then found a way to recreate the initial memories, by re-stimulating the same nerves with a memory-forming, high-frequency train of optical pulses. These re-conditioned rats once again responded to the original stimulation with fear, even though they had not had their feet re-shocked.

“We can cause an animal to have fear and then not have fear and then to have fear again by stimulating the nerves at frequencies that strengthen or weaken the synapses,” said Sadegh Nabavi, a postdoctoral researcher in the Malinow lab and the study’s lead author.

To me, this is simply mind blowing. Sure, it’s a simple memory, and it’s a memory that they created – but it’s a proof of concept. The researchers showed that it is possible to eliminate and then recreate a memory using certain stimuli – this is not something I was expecting to find out when I woke up.

Naturally, it’s much too premature to talk about actually altering memories in humans. There is still a long way (and many years) to go before we can even start discussing that – but as I said, it’s a proof of concept; and there are some closer clinical applications of this discovery, for example in Alzheimer’s disease.

“Since our work shows we can reverse the processes that weaken synapses, we could potentially counteract some of the beta amyloid’s effects in Alzheimer’s patients,” he said.

Journal Reference:
Sadegh Nabavi, Rocky Fox, Christophe D. Proulx, John Y. Lin, Roger Y. Tsien and Roberto Malinow. Engineering a memory with LTD and LTP. Nature, 2014 DOI: 10.1038/nature13294

New brain cells erase old memories

If you’re trying to hold on to old memories, then some new, fresh brain cells may be the last thing you need – a new research published in Science suggests that newly formed neurons in the hippocampus (an area in the brain responsible for memory formation) could remove previously stored information. This is perhaps the reason why childhood memories are so hard to recall.

“The finding was very surprising to us initially. Most people think new neurons mean better memory,” says Sheena Josselyn, a neuroscientist who led the study together with her husband Paul Frankland at the Hospital for Sick Children in Toronto, Canada.

In recent years, it was shown that humans, mice and many other mammals grow new neurons in the hippocampus throughout their lives – rapidly in youth, and slower as you age – especially if you don’t “train your brain”. However, this recent study has shown that this neuron formation could remove some of your old memories.

But why does this happen? Isn’t it a little counter intuitive for your own body to throw out your old memories? According to researchers, not so much.

“More neurons increase the capacity to learn new memories in the future,” she says. “But memory is based on a circuit, so if you add to this circuit, it makes sense that it would disrupt it.” Newly added neurons could have a useful role in clearing old memories and making way for new ones, says Josselyn.

Basically, your brain’s “hard drive” is starting to fill up, and it’s time to delete some of the old “files”.

In order to reach this conclusion, researchers studied newborn and adult mice on a conditioning task, training the animals to fear an environment in which they received repeated electric shocks. All the mice learned the task quickly, but whereas adult mice remembered it for several weeks, young mice only remembered it for about a day. This difference seems to correlate with differences in neural proliferation.

The researchers then tested the same thing in guinea pigs, which have a longer gestation period, and therefore, reduced brain development after birth (the brain does most of the developing during the gestation). Guinea pigs don’t have infantile amnesia (like mice and humans), but the researchers were able to mimic its effects in the animals through exercise or drugs that promote neuron growth.

“It’s incredibly impressive. They covered everything from genetic and pharmacological interventions, to behavioral interventions, to cross-species comparisons,” says Karl Deisseroth, a neuroscientist at Stanford University in California who is collaborating with the group on a separate project but did not contribute to the current study.

The work ethics in the study were indeed laudable, and hold valuable information about the relationship between neuronal development and long term memories.

Scientific Reference: Hippocampal Neurogenesis Regulates Forgetting During Adulthood and Infancy. Science 9 May 2014: DOI: 10.1126/science.1248903

Men and women’s brains are hard wired differently, study shows

Neural map of a typical man’s brain. Credits: National Academy of Sciences/PA

A new study which involved the analysis of over 1.000 brain scans confirmed what many intuitively believed for a long time: men and women’s brains are hard wired differently.

Maps of neural circuitry showed that on average women’s brains were highly connected across the left and right hemispheres, while men had better connections between the front and back areas of the brain. Surprisingly or not, these findings support the stereotypical ideas that men generally have improved perception and coordination, while women have better social skills.

Neural map of a typical woman’s brain. Photograph: National Academy of Sciences/PA

Ragini Verma, a researcher at the University of Pennsylvania, explains:

“If you look at functional studies, the left of the brain is more for logical thinking, the right of the brain is for more intuitive thinking. So if there’s a task that involves doing both of those things, it would seem that women are hardwired to do those better,” Verma said. “Women are better at intuitive thinking. Women are better at remembering things. When you talk, women are more emotionally involved – they will listen more.”

She then adds:

“I was surprised that it matched a lot of the stereotypes that we think we have in our heads. If I wanted to go to a chef or a hairstylist, they are mainly men.”

This is the biggest study to date that documents the differences between the brains of men and women. In addition from showing the gender differences, this also gave researchers a better picture of what happens in the brain for each sex at various ages. They hope that this can provide a better understanding of what happens at a neural level to patients suffering from brain disorders such as schizophrenia and depression.

Verma’s team used a technique called diffusion tensor imaging. Diffusion-weighted imaging (DWI) is a well-established magnetic resonance imaging (MRI) method for diagnosing problems such as cerebral ischemia. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively.

They looked at the brain scans of 428 males and 521 females aged eight to 22. The neural connections are basically a road system through which the brain carries out its traffic. The scans clearly showed significant differences, the most noticeable being greater connectivity between the left and right sides of the brain in women, while the connections in men were mostly confined to individual hemispheres. The only area of the brain where males had better inter-hemisphere connectivity is the cerebellum, which plays a vital role in motor control.

“If you want to learn how to ski, it’s the cerebellum that has to be strong,” Verma said.

The differences didn’t become noticeable by the age of 13, but clearly showed up on ages 14-17.

“It’s quite striking how complementary the brains of women and men really are,” Ruben Gur, a co-author on the study, said in a statement. “Detailed connectome maps of the brain will not only help us better understand the differences between how men and women think, but it will also give us more insight into the roots of neurological disorders, which are often sex-related.”

Journal Reference:

Madhura Ingalhalikar et al. Sex differences in the structural connectome of the human brain.  PNAS December 2, 2013, doi:10.1073/pnas.1316909110 

Memories Are Geo-tagged With Spatial Information

Kahana Videogame Still

A still from the game participants played. They made deliveries to stores, then were asked to recall what they had delivered. Copyright: Michael Kahana.

Trying to better understand how memories are stored inside a human brain, researchers from the University of Pennsylvania and Freiburg University used a video game in which people navigate through a virtual town delivering objects to specific locations; they found that brain cells add a geo-tag with spatial information to some memories, and this spacial information is activated immediately before the memory is recalled. Their work shows how spatial information is used in memories and why recalling a certain experience can quickly bring to mind the place where it happened.

“These findings provide the first direct neural evidence for the idea that the human memory system tags memories with information about where and when they were formed and that the act of recall involves the reinstatement of these tags,” said Michael Kahana, professor of psychology in Penn’s School of Arts and Sciences.

Michael Kahana.

Michael Kahana.

Prior to this experiment, Kahana and his colleagues had been studying epilepsy patients, trying to determine what happens inside of the patients’ brain, and the changes that occur during a seizure. In order to do this, they used patients which had electrode implanted in their brains, as part of their treatment, because the electrodes also transmit information from the patients’ brain.

Inspired by their previous research, they conducted a study which involved playing a simple video game on a bedside computer; the game was basically all about making deliveries to stores in a virtual city. Initially, volunteers had a period of time to make themselves familiar with the city, before the deliveries began. After that, the game began, and participants were only instructed where their next stop was, without being told what they were delivering. After they reached the destination, the game revealed what the item actually was and gave them the next stop.

After 13 deliveries, the game ended, and participants were asked to name as many items as possible, in whatever order they found easiest. Researchers tracked the neural activation associated with the formation of spatial memories (location of the stores), and the recall of episodic memories (the items that were delivered.

“A challenge in studying memory in naturalistic settings is that we cannot create a realistic experience where the experimenter retains control over and can measure every aspect of what the participant does and sees. Virtual reality solves that problem,” Kahana said. “Having these patients play our games allows us to record every action they take in the game and to measure the responses of neurons both during spatial navigation and then later during verbal recall.”

By asking participants to recall the items they delivered instead of the places they visited, they checked whether spatial memory systems were being activated even when episodic memories were being accessed. They found that the “place cells” were also activated, even though the volunteers were only thinking about the items.

“During navigation, neurons in the hippocampus and neighboring regions can often represent the patient’s virtual location within the town, kind of like a brain GPS device,” Kahana said. “These so-called ‘place cells’ are perhaps the most striking example of a neuron that encodes an abstract cognitive representation.”

migraine

Migraines linked with abnormal brain arteries

migraineWe’re all swept from time to time by the occasional migraine, and rest assured you don’t want anyone around you when that time comes. Some people, however, suffer from migraines more often than others in what’s recently been classified as chronic migraines. It’s still unclear what causes them. Some studies point to dilation of blood vessels in the head, it’s even been attributed to abnormal neuronal signals, while most recently researchers  in the Perelman School of Medicine at the University of Pennsylvania report that the network of arteries supplying blood flow to the brain is more likely to be incomplete in people who suffer migraine.

“People with migraine actually have differences in the structure of their blood vessels – this is something you are born with,” said the study’s lead author, Brett Cucchiara, MD, Associate Professor of Neurology. “These differences seem to be associated with changes in blood flow in the brain, and it’s possible that these changes may trigger migraine, which may explain why some people, for instance, notice that dehydration triggers their headaches.”

The arterial supply of blood to the brain is protected by a series of connections between the major arteries, termed the “circle of Willis” after the English physician who first described it in the 17th century.   People with migraine, particularly migraine with aura – a migraine that’s preceded or accompanied by sensory warning signs or symptoms, such as flashes of light, blind spots, or tingling in your hand or face –  are more likely to be missing components of the circle of Willis, according ot University of Pennsylvania researchers.

In a study of 170 people from three groups – a control group with no headaches, those who had migraine with aura, and those who had migraine without aura – the team found that an incomplete circle of Willis was more common in people with migraine with aura (73 percent) and migraine without aura (67 percent), compared to a headache-free control group (51 percent). The team used magnetic resonance angiography to examine blood vessel structure and a noninvasive magnetic resonance imaging method pioneered at the University of Pennsylvania, called Arterial spin labeling (ASL), to measure changes in cerebral blood flow.

“Abnormalities in both the circle of Willis and blood flow were most prominent in the back of the brain, where the visual cortex is located.  This may help explain why the most common migraine auras consist of visual symptoms such as seeing distortions, spots, or wavy lines,” said the study’s senior authorJohn Detre, MD, Professor of Neurology and Radiology.

Migraine affects an estimated 28 million Americans, causing significant disability in day to day activities. Both migraine and incomplete circle of Willis are common, and the observed association is likely one of many factors that contribute to migraine in any individual.

source

Scientists discover molecular trigger for itch

An itch is a sensation that causes the desire or reflex to scratch. Researchers have long tried to characterize itch, but in its typical annoying fashion, the sensation resisted any such attempts. For a very long time, the itch has been thought of as a low-level form of pain, but now, a new study conducted on mice suggests that it is indeed a distinct sensation, with a dedicated neural circuit linking cells in the periphery of the body to the brain.

itchNeuroscientists Mark Hoon and Santosh Mishra of the National Institute of Dental and Craniofacial Research in Bethesda, Maryland, tried to find the exact molecule which triggers the sensation of itch by screening genes in sensory neurons that are activated by touch, heat, pain and itch. They found that one particular protein, called natriuretic polypeptide b, or Nppb, was expressed in only a subset of these neurons.

Mutant mice lacking this this protein, did not respond to itch-inducing compound – but interestingly enough, they didn’t respond to heat and pain. But what’s even more interesting is that when Nppb was injected into the mice, it send them into a scratching frenzy. This occurred both in the mutants and in control mice.

“Our research reveals the primary transmitter used by itch sensory neurons and confirms that itch is detected by specialized sensory neurons,” says Hoon.

According to Glenn Giesler, a neuroscientist at the University of Minnesota in Minneapolis, the result “explains problems in the literature and provides a very testable hypothesis for how itch works”.

Previous research suggested that gastrin-releasing peptide, or GRP, was the neurotransmitter behind itches, but as Hoon and Misha showed (almost beyond the shadow of a doubt) is that GRP is not the primary trigger, but is still involved in the process, and injecting GRP into mice lacking either Nppb or its receptor did produce strong scratching responses.

Furthermore, mice in which GRP receptors were inhibited did not engage in scratching behaviour, even with spinal-cord injection of Nppb. This seems to suggest that GRP-releasing neurons are downstream of Nppb in the transmission of the itch sensation.

“This model fits better with what everyone else is seeing,” says Sarah Ross, a neuroscientist at the University of Pittsburgh in Pennsylvania.

The neural pathways are similar, though not identical, to those in mice. It remains to be seen if Nppb plays the same role in humans, or if there is something different involved.

“Antihistamines work for a few forms of itch, but for the vast majority they do nothing,” he says. “This research introduces a brand new target for clinical treatment.”

Via Nature

Flipping a single “molecular switch” makes an old mouse brain young

A single molecular switch can make the transition between the active, malleable brain of an adolescent and the mature, stable brain of an adult; yep, a single gene can turn us back to the childlike curiosity we exhibit as adolescents.

A neuron cultured for the study. Via Yale University.

A neuron cultured for the study. Via Yale University.

Researchers have known for quite a while that adolescent brains are typically more malleable (or plastic) than adult ones, allowing them  for example to learn foreign languages much faster and recover from any brain injuries. The relative rigidity of the adult brain stems (mostly) from the function of a single gene that slows the rapid change in synaptic connections between neurons. Now, Yale researchers have identified the key genetic switch for brain maturation a study released March 6 in the journal Neuron.

The Nogo Receptor 1 gene supresses the high levels of plasticity in the adolescent brain as you grow up. In mice without this gene, juvenile levels of brain plasticity persist throughout adulthood, allowing them to keep the young, learning-avid brain as they age. Furthermore, the supression of the gene in older mice also reset their brains to the adolescent levels of plasticity.

“These are the molecules the brain needs for the transition from adolescence to adulthood,” said Dr. Stephen Strittmatter. Vincent Coates Professor of Neurology, Professor of Neurobiology and senior author of the paper. “It suggests we can turn back the clock in the adult brain and recover from trauma the way kids recover.”

Not only can we recover from trauma the way children do, but we can also literally improve our minds, indirectly keeping the child-like curiosity avid as we age, leading to better and healthier lives. So far, this study has only been conducted on mice, and it will most likely take a while before it is adapted to humans, but I for one am holding my breath. To think that such a big change depends on a single gene…

“We know a lot about the early development of the brain,” Strittmatter said, “But we know amazingly little about what happens in the brain during late adolescence.”

Obama funds brain mapping, interesting questions arise

This week, the Obama administration has announced plans to pursue a 10-year, $3 billion research effort aimed at mapping the human brain in “its entirety”. The project, called the Brain Activity Map, is designed to help scientists better understand how the ~100 billion neurons interact in our brains. Initially, the announcement was met with applause, as  the study could prove extremely useful in fighting diseases such as Parkinson’s and Alzheimer’s and stimulate employment in the sciences. But as the dust settles in, some sticky questions are starting to pop up.

brains map

In terms of science funding, the Obama administration has been quite frugal and hesitant to commit to projects of this size. Brain research especially is not cheap, and some even question if we have the right technology to study it at the moment – given how nanotech is still in its early years.

It’s pretty safe to say that odds are artificial intelligence will have the most to gain following this research. Understanding how our brain works means we will be more able to create others in our image, and in a raport released by Obama’s cabinet, this initiative is expected to actually boost the economy, providing a $800 billion return for a $3 billion investment – much like the Human Genome Project did.

But there are more striking differences from the HGP. For starters, the mapping of the Human Genome had a clear (albeit misleaded) idea behind it: knowledge of the human genome would allow us to map human beings based on their distinct genetic codes. This project, the mapping of the brain – we’re so far from understanding the implications of such a map that the goals are just vague. But the biggest difference is probably the most worrying one.

A big part of the funding and research activities will be provided by DARPA: the Defense Advanced Research Projects Agency, a government organization responsible for the development of new and innovative military technologies, including drones. Now, the military had absolutely no involvement in the HGP, which makes a lot of sense. This involvement alone is enough to raise many question marks. Also, the American government was quite silent about the implications of this involvement The inclusion of money for DARPA clearly suggests the interest in military applications of this research, be it for AI drones or something else.

U-shaped trap

Slime can navigate using external memory, despite having no brain – a precursor to the nervous system?

The filaments created by a slime mold, along with the slime left behind on paths it discards.

The filaments created by a slime mold, along with the slime left behind on travel paths. These gooey deposits allows it to “remember” where it’s been before.

Scientists at University of Sydney have been studying for the past few years one of the most peculiar events in nature. It seems that a living slime, no less, no more, is capable of reading information and remembering its past “steps” acting on some sort of external memory, this despite the fact that it has no brain, not even one single neuron. The researchers believe that the slime’s mechanism might actually be one of the initial precursors of the most primitive nervous system.

The slime mold the Austrilian scientists studied is  Physarum polycephalum, an odd creature with a nucleus and complex cells, but still miles away from multicellular animals; for comparison its close cousin is the famous lab guinea pig the Amoeba. When there’s food about, the slime stays as a single cell organism, however when food is scarce, it binds to other such slime cells morphing into an multi-nuclei organism visible with the naked eye, with a single purpose and direction. Scientists have found this to be advantageous, as the slime is able to move more efficient and  increase its chances of finding food when sticking together.

“The slime mold leaves behind a trail of slime everywhere it goes, which it can then detect later to recognize areas it has already been,” said biologist Chris Reid.

You don’t need a brain to find your way around

What’s curious however, is despite it having absolutely no neurons whatsoever, the slime is capable of remembering where it’s been before, and more than that – it’s capable of moving through an optimal path and reach a food resource. Researchers were fascinated by this behavior and put the organism to the test in a control environment. First the slime was put at the edge of an Y shaped maze, where food was put on both ends of the container, but with one of the Y arms already covered in slime trail. The results were staggering – in 39 of the 40 tests they ran, the slime mold avoided the arm that was pre-slimed.

“Even an organism without a (central) nervous system can effectively navigate complex environments,” the researchers write.

U-shaped trap

Next, the researchers put the slime to a more difficult test, and placed it in a similar container, this time U shaped, a pattern usually used for testing robots.  Physarum starts at the top, middle portion of the U-shaped container and ss tasked with reaching its goal, located beneath the U container where a sugar rich food source is located. The whole set-up is placed in a jelly environment inside a petri-dish. Since sugar diffuses inside the jelly, it creates a gradient which the slime remarkably can sense and follow to reach the sugar rich food source.  On an untreated surface, 96 percent of the specimens were able to steer through the trap to find a sugar solution within before the time limit of 120 hours. Then, the researchers covered the entire setup in slime so the mold had no way of telling what areas it had already visited, only about a third of the organisms succeeded in making their way to the food.

“The slime mold’s behavioral response strongly suggests that it can sense extracellular slime upon contact, and uses its presence as an externalized spatial memory system to recognize and avoid areas it has already explored,” the researchers write.

What this tells us is that the slime mold has somehow developed the ability to read its tracks and tell if its been in a place before or not; this way it can save energy and not forage through locations where effort has already been put. The scientists believe this externalized spatial memory could have been used by primitive organisms to solve the same types of problems more complex organisms are confronted with. Previous research has shown that slime mold can also solve mazes and anticipate periodic events. Maybe a similar organism, one of our very first forefathers, developed the very first brain cells after expanding from a similar external memory.

Findings were documented in the journal PNAS.

 

insert neural node here

Tap into the cockroach’s neural activity with the SpikerBox

insert neural node here

insert neural node here

Neurons are the absolute core components of the nervous system that transmit information through electrical and chemical signals. I once wondered how neural activity might sound like, and I imagined something like a huge gridline sprinkled with electricity bolts though out. I didn’t know about the SpikerBox, back then, though. It’s a gadget, developed by educational entrepreneurs Timothy Marzullo and Gregory Gage, which can measure the neural activity of various insects and can be employed in some very interesting experiments, like observing how neural activity is affected by temperature, external electrical signals or … pokes. Beware, you need to cut off a cockroach leg for science!

It’s a very simple set-up made out of a microprocessor,  two neural probes, and a speaker, everything powered by a 9V battery. In a demo video for the gadget, its creators explain how it works and how to use it. Just find an invertebrate, like an insect, from under your local rock, cut off one of its legs (it grows back). Then stick one of the needle probes in the femur, and the other a bit higher on the leg. What you’ll hear next is the electrical activity of the still living neural network in the leg. If you’re looking for some graphical representation as well, the device can be tethered to an iPhone or Android phone. Find out more about the SpikerBox at Backyard Brains.

neuron

Why the brain gets slower as we get older

From a certain age onward, humans seem to process information at a slower pace – learning new things becomes more difficult, remembering where you put the car keys seems to give headaches, and it gets ever worse as we age even more. Neuroscientists at the University of Bristol studying dysfunctional neural communication in Alzheimer patients demonstrated that the number one likely culprit to blame are the sodium channels, which are integral membrane proteins that have a direct influence on the degree of neural excitation. Although, the research was targeted on Alzheimer patients, the scientists found that the same degradation of Na+ channels in the brains of older, otherwise healthy individuals causes a loss of cognitive performance .

To encode and transmit information, the brain uses electrical signals. The researchers, lead by Professor Andy Randall and Dr Jon Brown from the University’s School of Physiology and Pharmacology, studied the electrical activity of the brain by recording the electrical signal in the hippocampus‘ cells, which plays a crucial role in the consolidation of short-term memory to long-term memory and spatial navigation. What the researchers were basically looking for was to determine the degree of neural excitation, whose main characteristic is the action potential.

“Much of our work is about understanding dysfunctional electrical signalling in the diseased brain, in particular Alzheimer’s disease. We began to question, however, why even the healthy brain can slow down once you reach my age. Previous investigations elsewhere have described age-related changes in processes that are triggered by action potentials, but our findings are significant because they show that generating the action potential in the first place is harder work in aged brain cells”, said Professor Randall.

neuronAn action potential is a brief, large electrical signal which instantly branches out in the rest of the cell, until it reaches the edge and activates the synapses made with the myriad of neighboring neurons. As we age, these action potentials are harder to trigger, and this relative reluctance arises from changes to the activation properties of membrane proteins called sodium channels, which mediate the rapid upstroke of the action potential by allowing a flow of sodium ions into neurons.

With this in mind, scientists might be able to develop treatments or drugs which could open more sodium channels, and thus improve cognitive abilities.

“Also by identifying sodium channels as the likely culprit for this reluctance to produce action potentials, our work even points to ways in which we might be able modify age-related changes to neuronal excitability, and by inference cognitive ability.”

[SciGuru] image credit

Scientists create brain with 12 seconds memory

The purple round thing you are looking at is actually a microscopic brain derived from rat neurons, just about 50 of them. Developed by researchers from the University of Pittsburg, it only has a memory of 12 seconds, which is about 11 more than what researchers were hoping for.

The brain was created in an attempt to artificially nurture a working brain into existence, thus providing more information about how neural networks function so efficiently and how our brain transmits electrical impulses are transmitted and data is stored. They did this by attaching a layer of protein to a silicon disk and adding braing cells extracted from embrionic rats.

The study was extremely successful, and as if growing and nurturing the tiny, functioning, donut-shaped brain in a petri dish wasn’t enough, they found that when they stimulate the neurons with electricity, the pulse circulates through the brain for a good 12 seconds, which is much more than they expected.

Alcohol helps the brain remember

The effects alcohol has on our brain are still not perfectly understood, and the general opinion and even some studies are biased because… well, generally speaking, alcohol is bad for you, and we tend to forget that students drink, teachers drink, scientists and artists drink. But according to a study conducted by the Waggoner Center for Alcohol and Addiction Research at The University of Texas at Austin, it may not be all bad: drinking alcohol causes certain areas of our brain to learn and remember better.

Well not quite... but the picture is just too funny

“Usually, when we talk about learning and memory, we’re talking about conscious memory,” says Morikawa, whose results were published last month in The Journal of Neuroscience. “Alcohol diminishes our ability to hold on to pieces of information like your colleague’s name, or the definition of a word, or where you parked your car this morning. But our subconscious is learning and remembering too, and alcohol may actually increase our capacity to learn, or ‘conditionability,’ at that level.”

Morikawa’s study found that repeated ethanol exposure enhances synapticgo plasticity in a key area in the brain, which basically helps you learn and remember some things better. When you drink alcohol (or take cocaine or heroine, for example), the subconscious is learning to take more and more, and it wants more and more, but it doesn’t stop there. We become more and more receptive to subconscious memories and habits with respect to food, music, even people and social situations.

If you take alcoholics, they aren’t addicted to the pleasure and relief they get with drinking alcohol; it’s the environmental, behavarioral and social changes they want so badly and which trigger dopamine release in the brain.

“People commonly think of dopamine as a happy transmitter, or a pleasure transmitter, but more accurately it’s a learning transmitter,” says Morikawa. “It strengthens those synapses that are active when dopamine is released.”

But hey, don’t go shouting off to your friends that alcohol is good for you; just tell them that… maybe it’s not necessarily as bad as everybody things.

New imaging method reveals stunning methods of brain connections

The typical healthy human brain contains about 200 billion nerve cells, called neurons, all of which are connected through hundreds of trillions of small connections called synapses. One single neuron can lead to up to 10.000 synapses with other neurons, according to Stephen Smith, PhD, professor of molecular and cellular physiology.

Along with a team of researchers from the Stanford School of Medicine, he was able to quickly and accurately locate and count these synapses in unprecedented detail, using a new state of the art imaging system on a brain tissue sample. Because the synapses are so small and close to each other, it’s really hard to achieve a thorough understanding on the complex neuronal circuits that make our brain work. However, this new method could shed some new light on the problem; it works by combining high-resolution photography with specialized fluorescent molecules that bind to different proteins and glow in different colors. The computer power required to achieve the imagery was massive.

A synapse is less than a thousandth of a millimeter in diameter, and the spaces between them are not much bigger either. This method, array tomography, is at its starting years, but as time passes, it will probably become more and more reliable, and more and more efficient.

“I anticipate that within a few years, array tomography will have become an important mainline clinical pathology technique, and a drug-research tool,” Smith said. He and Micheva are founding a company that is now gathering investor funding for further work along these lines. Stanford’s Office of Technology Licensing has obtained one U.S. patent on array tomography and filed for a second.

Full study here.

Bacteria can make you happier AND smarter

Mycobacterium vaccae is a type of bacteria that naturally leaves in soil and has been in the attention of researchers for a while now, due to the fact that it decreases anxiety. Recent studies sugest that in fact, it also stimulates neuron growth and thus intelligence and the ability to learn.

smart-mouseDorothy Matthews and Susan Jenks from The Sage Colleges in Troy, New York believed this bacteria could have a beneficial impact on neurons too, and injected the bacteria in mice which, at first, led to a significantly increased serotonin production. However, researchers were interested in a more indirect effect.

“Since serotonin plays a role in learning we wondered if live M. vaccae could improve learning in mice.”

In order to assess this assumption, they took two groups and injected only one of them with the bacteria, and then tested them in a maze. The difference was easy to notice.

“We found that mice that were fed live M. vaccae navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice.”

The mice were then tested after the bacteria was removed from their organisms. When they were tested immediatly afterward, they still did better than their counterparts, but not as good as the first time. Three weeks later, they were tested again. The results were still slightly better, but not statistically relevant. This seems to suggest that the boost to learning is of temporary nature, but applied to humans with a greater cognitive capacity, the results might be more spectacular.

“This research suggests that M. vaccae may play a role in anxiety and learning in mammals. It is interesting to speculate that creating learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks.”

Learning keeps your brain healthy

brain-1Just like any muscle in your body, if not used, the brain starts to degrade as time passes; this has been known for quite a while, but recently, a team from UC Irvine provided the first visual evidence of how learning protects the brain, thus proving that mental stimulation fights against the degrading effects that aging has on your brain.

The team of neuroscientists led by Lulu Chen and Christine Gall developed a novel visualization technique and found that everyday forms of learning stimulate the neuron receptors that keep the brain cells going at top gear. The receptors are activated by a protein called brain-derived neurotrophic factor, which facilitates the growth and differentiation of the connections, or synapses, responsible for communication among neurons.

“The findings confirm a critical relationship between learning and brain growth and point to ways we can amplify that relationship through possible future treatments,” says Chen, a graduate researcher in anatomy & neurobiology.

Researchers find marijuana spreads and prolongs pain

We’ve all endured some kind of physical pain, more or less intense. When you hit your finger while hammering, for example, the pain is really intense, but passes away (at least mostly) in just a few moments. So scientists were trying to find out why is it that some intense pains pass so quickly and why some have to be endured for more time.

Researchers from the University of Texas Medical Branch of Galveston believe they have, at least partially, found the answer, which is, believe it or not, in a group of compounds that include cannabinoids, the active ingredients in marijuana, or weed, as anybody under 40 (and not only) knows it as. This proves to be very interesting, given the recent research and interest in medical use of marijuana for pain relief. According to this study, the results are the exact opposite, as endocannabinoids, which are produced by human body (and not only) prolong pain istead of damping it down.

“In the spinal cord there’s a balance of systems that control what information, including information about pain, is transmitted to the brain,” said UTMB professor Volker Neugebauer, one of the authors of the Science article, along with UTMB senior research scientist Guangchen Ji and collaborators from Switzerland, Hungary, Japan, Germany, France and Venezuela. “Excitatory systems act like a car’s accelerator, and inhibitory ones act like the brakes. What we found is that in the spinal cord endocannabinoids can disable the brakes.”

In order to get to this conclusion they applied a ‘biochemical mimic’ to the inhibitory neurons on slices they took from mouse spinal cord. Electrical signals that should have produced an inhibitory response were ignored. They then proceeded to analyze spinal cord slices taken from genetically engineered mice that lacked receptors for the endocannabinoid molecules and they found that the so called ‘brakes’ work.

“To sum up, we’ve discovered a novel mechanism that can transform transient normal pain into persistent chronic pain,” Neugebauer said. “Persistent pain is notoriously difficult to treat, and this study offers insight into new mechanisms and possibly a new target in the spinal cord.”

Brain neurons can remodel connections, MIT shows

interneuron

Representation of an interneuron

Contrary to almost a half of century of research, Elly Nedivi, associate professor of neurobiology at the Picower Institute for Learning and Memory and colleagues found that a certain type of neuron that plays a crucial part in autism spectrum disorders is able in fact to remodel itself. It can do this in a strip of brain tissue just 4 times thicker than your average paper.

“This work is particularly exciting because it sheds new light on the potential flexibility of cerebral cortex circuitry and architecture in higher-level brain regions that contribute to perception and cognition,” said Nedivi, who is also affiliated with MIT’s departments of brain and cognitive sciences and biology. “Our goal is to extract clues regarding the contribution of structural remodeling to long-term adult brain plasticity — the brain’s ability to change in response to input from the environment — and what allows or limits this plasticity.”

To prove this, she showed that genetics are not determinant for an internenuron’s capacity to remodel, but that it’s rather imposed by the circuitry within the layers of the cortex. So the genetic lineage would come in second place, thus meaning that this type of neurons could actually remodel.

“Our findings suggest that the location of cells within the circuit and not pre-programming by genes determines their ability to remodel in the adult brain,” Nedivi said. “If we can identify what aspect of this location allows growth in an otherwise stable brain, we can perhaps use it to coax growth in cells and regions that are normally unable to repair or adjust to a changing environment. Knowing that neurons are able to grow in the adult brain gives us a chance to enhance the process and explore under what conditions we can make it happen,” she adds. “In particular, we need to pay more attention to the unique interneuron population that retains special growth features into adulthood.”