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Great minds may think alike, but all minds look alike -- ScienceDaily

The (skeleton) structure of the brain is like a road map consisting of many narrow streets (i.e., weak links), and a small fraction of highways each containing thousands of lanes (i.e., very strong links). Such a diverse road map could either be a spontaneous outcome of a random brain activity, or alternatively could be directed by a meaningful learning activity, where the "highways" direct the information flow in the brain. "A byproduct of dendritic learning is the wide spectrum of link strengths. The dendritic learning enables us to offer an explanation for an additional universal phenomenon observed in all brains and indicates its important role," said Prof. Kanter, whose research team includes Herut Uzan, Shira Sardi, Amir Goldental and Roni Vardi. The underlying mechanism is a fast response of a neuron to its strong entry compared to a slow response to a weak one. "The mechanism is similar to a pool filled through a wide pipe or through a narrow one. The wide pipe fills the pool faster," explained the research team.

Fundamental Rule of Brain Plasticity Discovered - Neuroscience News

Our brains are famously flexible, or “plastic,” because neurons can do new things by forging new or stronger connections with other neurons. But if some connections strengthen, neuroscientists have reasoned, neurons must compensate lest they become overwhelmed with input. In a new study in Science, researchers at the Picower Institute for Learning and Memory at MIT demonstrate for the first time how this balance is struck: when one connection, called a synapse, strengthens, immediately neighboring synapses weaken based on the action of a crucial protein called Arc. Senior author Mriganka Sur said he was excited but not surprised that his team discovered a simple, fundamental rule at the core of such a complex system as the brain, where 100 billion neurons each have thousands of ever-changing synapses. He likens it to how a massive school of fish can suddenly change direction, en masse, so long as the lead fish turns and every other fish obeys the simple rule of following the fish right in front of it.

Absence epilepsy: When the brain is like 'an orchestra without a conductor' -- ScienceDaily

"Normally the human brain, like an orchestra, is playing beautiful music and every player can understand what the others are playing. We thought that when a seizure started, the 'orchestra of neurons' would play extremely loud and intense music. And when the seizure ended, the neurons would go back to playing monotonous music," Maheshwari said. "Instead, we found that during an absence seizure the volume of the music went down and the 'musicians' were playing music without coordinating with others. Most of them were not playing at all, as if the conductor was not there anymore. When the seizure ended, it was like the conductor had returned and organized the musicians to play harmoniously again."

Acupuncture alters key neurotransmitters

Steffensen is going beyond the previous claims and is studying the neuroscience behind acupuncture. He has shown it to be an effective method of activating pathways from the peripheral nervous system to the central nervous system. Here's how: Those suffering from withdrawal have dysregulated dopamine levels in the midbrain reward/pleasure system This causes dysregulation of GABA neurons in this system, and they become hyperactive, inhibiting dopamine neurons and lowering dopamine levels during withdrawl Lowered dopamine levels is the driving force for relapse Accupuncture stimulation inhibits GABA neurons This restores dopamine levels and effectively lowers the driving force for relapse

Melatonin in Synaptic Impairments of Alzheimer's Disease. - PubMed - NCBI

It is reported that both the melatonin deficit and synaptic impairments are present in the very early stage of AD and strongly contribute to the progress of AD. In the mammalian brains, the effects of melatonin are mainly relayed by two of its receptors, melatonin receptor type 1a (MT1) and 1b (MT2). To have a clear idea on the roles of melatonin in synaptic impairments of AD, this review discussed the actions of melatonin and its receptors in the stabilization of synapses, modulation of long-term potentiation, as well as their contributions in the transmissions of glutamatergic, GABAergic and dopaminergic synapses, which are the three main types of synapses relevant to the synaptic strength. The synaptic protective roles of melatonin in AD treatment were also summarized. Regarding its protective roles against amyloid-β neurotoxicity, tau hyperphosphorylation, oxygenation, inflammation as well as synaptic dysfunctions, melatonin may be an ideal therapeutic agent against AD at early stage.

New findings explain how melatonin promotes sleep: Discovery may lead to new therapy for insomnia -- ScienceDaily

The experiments singled out one receptor, MT1, as the mechanism via which melatonin acts to inhibit the specific orexin neurons that wake you up. This discovery could help lead to medications that target only the MT1 receptor instead of multiple receptors, which could lead to fewer side effects for those who take sleep-promoting drugs. "Melatonin has been used as a sleep drug for many years, but people didn't know how it worked," Thakkar said. "Our research suggests that if you target the melatonin MT1 receptor, you will get the most sleep with minimal side effects."

The Brain Learns Completely Differently than We've Assumed Since the 20th Century - Neuroscience News

The newly suggested learning scenario indicates that learning occurs in a few dendrites that are in much closer proximity to the neuron, as opposed to the previous notion. “Does it make sense to measure the quality of air we breathe via many tiny, distant satellite sensors at the elevation of a skyscraper, or by using one or several sensors in close proximity to the nose? Similarly, it is more efficient for the neuron to estimate its incoming signals close to its computational unit, the neuron,” says Kanter. Hebb’s theory has been so deeply rooted in the scientific world for 70 years that no one has ever proposed such a different approach. Moreover, synapses and dendrites are connected to the neuron in a series, so the exact localized site of the learning process seemed irrelevant. Another important finding of the study is that weak synapses, previously assumed to be insignificant even though they comprise the majority of our brain, play an important role in the dynamics of our brain. They induce oscillations of the learning parameters rather than pushing them to unrealistic fixed extremes, as suggested in the current synaptic learning scenario.

Attention deficit disorders could stem from impaired brain coordination: Researchers uncover link absent between brain regions in attention deficit hyperactivity disorder, schizophrenia -- ScienceDaily

When the researchers attached probes to the mice to measure brain activity, they found mice without ErbB4 had brain regions that were acting independently, rather than together in synchrony. In particular, the researchers studied the prefrontal cortex -- normally associated with decision-making -- and the hippocampus -- a region that supports memory. These two regions coordinate for a variety of brain tasks, including memory and attention. "We found top-down attention, previously thought to be controlled by the prefrontal cortex, also involves the hippocampus in a manner where the two regions are highly synchronized when attention is high," says Mei. "Our findings give importance to synchrony between the prefrontal cortex and hippocampus in top-down attention and open up the possibility that attention deficit disorders, like ADHD, might involve impairments in the synchrony between these two regions." According to the new study, ErbB4 coordinates a cascade of brain signals that "bridge" the two regions. ErbB4 itself encodes a receptor found on the surface of brain cells. The study found that when a protein (neuregulin-1) attaches to the ErbB4 receptor, it triggers a chain reaction that ultimately determines neurotransmitter levels in the prefrontal cortex and hippocampus. Without ErbB4, neurotransmitter levels go awry. The researchers discovered mice lacking ErbB4 have low levels of a particular neurotransmitter -- GABA, or gamma-aminobutyric acid -- in their brain. Low GABA levels can lead to impaired top-down attention in the prefrontal cortex, and impairs how the prefrontal cortex can efficiently coordinate with the hippocampus. The researchers concluded that ErbB4 helps link the two brain regions to maintain attention.

Older adults grow just as many new brain cells as young people -- ScienceDaily

The researchers from Columbia University and New York State Psychiatric Institute found that even the oldest brains they studied produced new brain cells. "We found similar numbers of intermediate neural progenitors and thousands of immature neurons," they wrote. Nevertheless, older individuals form fewer new blood vessels within brain structures and possess a smaller pool of progenitor cells -- descendants of stem cells that are more constrained in their capacity to differentiate and self-renew.

When the brain's wiring breaks: Key molecular details of a common type of brain injury and a possible new treatment strategy -- ScienceDaily

"Neurologists know this," said Taylor, a member of the UNC Neuroscience Center. "It's why they promote physical therapy and retraining for people who suffer head injury. During this extended period of excitability, PT and retraining can help guide injured neurons along beneficial pathways."

Is your stress changing my brain? Stress isn't just contagious; it alters the brain on a cellular level -- ScienceDaily

The study's lead author, Toni-Lee Sterley, a postdoctoral associate in Bains' lab said, "What was remarkable was that CRH neurons from the partners, who were not themselves exposed to an actual stress, showed changes that were identical to those we measured in the stressed mice."

Birth of new neurons in the human hippocampus ends in childhood: Adult 'neurogenesis,' observed in other species, appears not to occur in humans -- ScienceDaily

The researchers found plentiful evidence of neurogenesis in the dentate gyrus during prenatal brain development and in newborns, observing an average of 1,618 young neurons per square millimeter of brain tissue at the time of birth. But the number of newborn cells sharply declined in samples obtained during early infancy: dentate gyrus samples from year-old infants contained fivefold fewer new neurons than was seen in samples from newborn infants. The decline continued into childhood, with the number of new neurons declining by 23-fold between one and seven years of age, followed by a further fivefold decrease by 13 years, at which point neurons also appeared more mature than those seen in samples from younger brains. The authors observed only about 2.4 new cells per square millimeter of DG tissue in early adolescence, and found no evidence of newborn neurons in any of the 17 adult post-mortem DG samples or in surgically extracted tissue samples from 12 adult patients with epilepsy.

Understanding the smallest brain circuits: Researchers reveal how anatomically distinct microcircuit brain networks suppress each other, compete and collaborate -- ScienceDaily

"We observe that when some neurons speed up, others slow down-and they do this in a coordinated fashion over several seconds," Galán said. "What we are discovering here, revealing for the first time, is a mode of operation of the brain circuits that shows you cannot have all of your networks operating at once," he said. Galán and his team explain those two anatomically distinct and competing networks in the smallest of the brain's microcircuits, calling them "anti-correlated cortical networks," in a recent issue of Scientific Reports. Co-authors include biology Professor Hillel Chiel and undergraduate students Nathan Kodama (first author), Tianyi Feng, James Ullett and Siddharth Sivakumar. Galán said the discovery was especially gratifying because it culminates the testing of a mathematical model he developed a decade ago. "That was a theoretical prediction-the idea that the wiring of brain circuits could be inferred from their spontaneous activity," he said. "When we were finally able to test this idea experimentally, we discovered the competing neural networks; it all came together in this study."

New neurons in the adult brain are involved in sensory learning -- ScienceDaily

The scientists from the Institut Pasteur and the CNRS observed that the new neurons were able to react differently to an odor depending on the consequences associated with that sensory experience, such as whether or not there would be a reward. They also demonstrated that olfactory learning, in which the mice had to associate an odor with positive reinforcement, became easier once the new neurons had been activated. Finally, simply activating these adult-born neurons could be assimilated with a reward-predicting odor. In short, this research shows that adult-born neurons are involved in the value associated with sensory stimuli rather than just the identification of the nature of a given sensory stimulus. It demonstrates that reward-motivated learning depends largely on adult neurogenesis.

Memories and recursion to the mean

The behavioral data revealed that as the rat awaited the second stimulus of the trial, the memory of the first stimulus shifted towards the mean of preceding stimuli. The experiment thus confirmed the sliding of memory towards the expected value, a phenomenon that earlier studies have termed 'contraction bias.'

Neurons get the beat and keep it going in drumrolls -- ScienceDaily

The researchers recorded the activities of individual neurons in the hippocampus, which is located in the lower center of the brain, with a robotic device called a patch clamp. It's a hollow glass needle one micron in diameter that latches onto a single neuron via suction and measures its electrical activity. The researchers observed electrical rumblings, symbolized here by a drumroll. And they observed spikes, symbolized here by a cymbal crash. Though the pattern of rumblings wasn't uniform, it rose and fell like a drumroll undulating between softer and louder volumes. Spikes occurred much more rarely than drumbeats, but with notable timing. "The spikes repeated in the same spots with high precision, so they weren't just random," Singer said. "They came around the peaks of rumblings, not always right on top of a peak but within a hair of it." It would be like a cymbal crash hitting not every time, but every few times the undulating drumroll topped a volume peak. And the drumroll-cymbal-crash patterns sustained themselves for surprisingly long periods. "The time periods of activity that was structured like this were much longer than we expected," Singer said. "People have shown sustained periods of signaling like this for 100 to 300 milliseconds before, but this appears to be the first time it's been seen for 900 milliseconds (nearly a full second), and it may go on even longer."

Midbrain 'start neurons' control whether we walk or run -- ScienceDaily

The researchers identify populations of 'start neurons' and show, for the first time, how the two regions in the midbrain can act both in common or separately to control speed and to select context dependent locomotor behaviours. "By identifying the midbrain 'start' neurons we complement a previous study where we found 'stop cells' in the brainstem that halt locomotion. Together, the start and stop cells define the episodic nature of locomotion," says Ole Kiehn. The study breaks new grounds in locomotor control and is important for understanding the normal brain function in mice. And the authors believe that the results might benefit humans with disabled locomotion as well.

Neurons aren't binary

In an article published today in the journal Scientific Reports, the researchers go against conventional wisdom to show that each neuron functions as a collection of excitable elements, where each excitable element is sensitive to the directionality of the origin of the input signal. Two weak inputs from different directions (e.g., "left" and "right") will not sum up to generate a spike, while a strong input from "left" will generate a different spike waveform than that from the "right." "We reached this conclusion using a new experimental setup, but in principle these results could have been discovered using technology that has existed since the 1980s. The belief that has been rooted in the scientific world for 100 years resulted in this delay of several decades," said Prof. Kanter and his team of researchers, including Shira Sardi, Roni Vardi, Anton Sheinin, and Amir Goldental.

Some video games are good for older adults' brains -- ScienceDaily

"3-D video games engage the hippocampus into creating a cognitive map, or a mental representation, of the virtual environment that the brain is exploring.," said West. "Several studies suggest stimulation of the hippocampus increases both functional activity and gray matter within this region." Conversely, when the brain is not learning new things, gray matter atrophies as people age. "The good news is that we can reverse those effects and increase volume by learning something new, and games like Super Mario 64, which activate the hippocampus, seem to hold some potential in that respect," said West. Added Belleville: "These findings can also be used to drive future research on Alzheimer's, since there is a link between the volume of the hippocampus and the risk of developing the disease."

Spatial and Sex-Dependent Responses of Adult Endogenous Neural Stem Cells to Alcohol Consumption: Stem Cell Reports

hronic alcohol abuse results in alcohol-related neurodegeneration, and critical gaps in our knowledge hinder therapeutic development. Neural stem cells (NSCs) are a subpopulation of cells within the adult brain that contribute to brain maintenance and recovery. While it is known that alcohol alters NSCs, little is known about how NSC response to alcohol is related to sex, brain region, and stage of differentiation. Understanding these relationships will aid in therapeutic development. Here, we used an inducible transgenic mouse model to track the stages of differentiation of adult endogenous NSCs and observed distinct NSC behaviors in three brain regions (subventricular zone, subgranular zone, and tanycyte layer) after long-term alcohol consumption. Particularly, chronic alcohol consumption profoundly affected the survival of NSCs in the subventricular zone and altered NSC differentiation in all three regions. Significant differences between male and female mice were further discovered.

Your brain does not process information and it is not a computer | Aeon Essays

Worse still, even if we had the ability to take a snapshot of all of the brain’s 86 billion neurons and then to simulate the state of those neurons in a computer, that vast pattern would mean nothing outside the body of the brain that produced it. This is perhaps the most egregious way in which the IP metaphor has distorted our thinking about human functioning. Whereas computers do store exact copies of data – copies that can persist unchanged for long periods of time, even if the power has been turned off – the brain maintains our intellect only as long as it remains alive. There is no on-off switch. Either the brain keeps functioning, or we disappear. What’s more, as the neurobiologist Steven Rose pointed out in The Future of the Brain (2005), a snapshot of the brain’s current state might also be meaningless unless we knew the entire life history of that brain’s owner – perhaps even about the social context in which he or she was raised.

'Multi-dimensional universe' in brain networks: Using mathematics in a novel way in neuroscience, scientists demonstrate that the brain operates on many dimensions, not just the 3 dimensions that we are accustomed to -- ScienceDaily

Using algebraic topology in a way that it has never been used before in neuroscience, a team from the Blue Brain Project has uncovered a universe of multi-dimensional geometrical structures and spaces within the networks of the brain. The research, published today in Frontiers in Computational Neuroscience, shows that these structures arise when a group of neurons forms a clique: each neuron connects to every other neuron in the group in a very specific way that generates a precise geometric object. The more neurons there are in a clique, the higher the dimension of the geometric object. "We found a world that we had never imagined," says neuroscientist Henry Markram, director of Blue Brain Project and professor at the EPFL in Lausanne, Switzerland, "there are tens of millions of these objects even in a small speck of the brain, up through seven dimensions. In some networks, we even found structures with up to eleven dimensions." Markram suggests this may explain why it has been so hard to understand the brain. "The mathematics usually applied to study networks cannot detect the high-dimensional structures and spaces that we now see clearly."

Diverse populations make rational collective decisions -- ScienceDaily

The team found that individual ants had different yet consistent preferences. Some of the ants were happy to feed on either of the two solutions. Picky ants refused to feed from either. A third "middle" group consistently chose the solution with a higher concentration. These varied choices demonstrated that individual ants had individual thresholds to the sucrose concentration and made yes/no binary decisions accordingly. The researchers then fed each colony again with the differing sucrose solutions and found that the majority of the ants in all six experimental colonies chose the 4.0% sucrose solution, without being influenced by other ants in the colony. The "collective" decision of the colony was thus for the more nourishing solution. "Importantly, neither ants with a low threshold and high threshold contributed to the collective decision making, since the former didn't care about the concentration and the latter refused both concentrations. Thus, the decision maker was the middle group which preferred the higher concentration," says Hasegawa. "The study demonstrates simple yes/no judgements by individuals can lead to a collective rational decision, without using quality-graded responses, when they have diverse thresholds in the population," he continued. This mechanism can be applied to various fields including brain science, behavioural science, swarm robotics and consensus decision-making in human societies, conclude the researchers.

What Is This Thing Called Consciousness?

Yet the cerebellum has everything you expect of neurons. It has gorgeous neurons. In fact, some of the most beautiful neurons in the brain, so-called Purkinje cells, are found in the cerebellum. Why does the cerebellum not contribute to consciousness? It has a very repetitive and monotonous circuitry. It has 69 billion neurons, but they have simple feed-forward loops. So I believe the way the cerebellum is wired up does not give rise to consciousness. Yet another part of the brain, the cerebral cortex, seems to be wired up in a much more complicated way. We know it’s really the cortex that gives rise to conscious experience.

Bipolar disorder: New method predicts who will respond to lithium therapy -- ScienceDaily

Wondering whether the differences could be predictive, the team trained a computer program to recognize the variations between the profiles of responders and nonresponders using the firing patterns of 450 total neurons over six independent training rounds. In each round, they started fresh with the neurons of five of the patients to train the system. They then tested the system with the neurons of the sixth patient, whose lithium status was known to the team but not to the program. They repeated the process five more times, which allowed them to build essentially six independent models. Each model was trained on the data from five out of the six patients, leaving a different patient out of the training data each time, and then letting the model classify this remaining patient as a responder or nonresponder. Using the firing patterns of just five of any patient's neurons, the system identified the person as a responder or nonresponder with 92 percent accuracy.

Mouse study identifies new method for treating depression: Inhibiting brain enzyme alleviates depression, and does it much faster than conventional antidepressants -- ScienceDaily

Palmer and team unraveled a previously underappreciated molecular process that can influence mouse models of depression. Here's how the process works: Cells generate energy. In doing so, they produce a byproduct. That byproduct inhibits neurons and thus influences various behaviors. Typically, the enzyme GLO1 removes this byproduct, but inhibiting GLO1 can also increase the activity of certain neurons in a beneficial way. In mice, Palmer and others have shown that more GLO1 activity makes mice more anxious, but less was known about the system's effect on depression. Palmer and team wondered if they could reduce signs of depression by inhibiting the GLO1 enzyme. The researchers used several different antidepressant tests. They compared responses in three groups of mice: 1) untreated, 2) treated by inhibiting GLO1, either genetically or with an experimental compound, and 3) treated with Prozac, a selective serotonin reuptake inhibitor commonly used to treat depression. The first tests they used were the tail suspension test and the forced swim tests, which are often used to determine whether or not a compound is an antidepressant. In this case, the answer was yes. The other tests -- chronic forced swim test, chronic mild stress paradigm and olfactory bulbectomy -- are well-established measures that can also be used to measure how long it takes for an antidepressant to take effect. In each of these tests, inhibiting the GLO1 enzyme reduced depression-like symptoms in five days, whereas it took 14 days for Prozac to have the same effect. While this new approach to treating depression has so far only been tested in mice and it will take many years of development before a GLO1 inhibitor could be tested in humans, the researchers are excited to find that new, unexplored approaches to treating depression are out there.