#There s a thermostat that stops neurons from spazzing out Brandeis University rightoriginal Studyposted by Leah Burrows-Brandeis on October 17 2013for the first time scientists have seen evidence in a living animal of a hermostatthat controls
with remarkable precision how often neurons fire. Neurons make new pathways and connections as our brain processes new information.
In order to do this individual neurons use an internal gauge to maintain a delicate balance that keeps our brains from becoming too excitable.
Scientists have theorized long a larger internal system monitors these individual gauges like a neural thermostat regulating average firing rates across the whole brain.
Without this thermostat they reasoned our flexible neurons would fire out of control making bad connections or none at all.
Turrigiano and colleagues observed in vivo that neocortical neurons cells that control higher functions such as sight language
This study demonstrated that during this period neurons are constantly elf-tuningto adjust for changes in environmental inputs says postdoctoral fellow Keith Hengen the paper s first author. f something is disturbed during that critical period
of early childhood development functioning neurons can self-adjust and return to their set-point average firing ratehengen says.
In this study published in the journal Neuron researchers studied young rats that temporarily lost vision in one eye.
But within the next 48 hours those neurons rebounded back to their set-point rateâ##like a cold house heating up.
This homeostatic mechanism keeps neurons on an even keel even as they change in response to learning development
The technique speeds up protein production at synapses. These proteins are required to make a memory.
Researchers have discovered that in nerve cells the production process for memory proteins is preassembled already at the synapse
when it s the wrong timesays Wayne Sossin a neuroscientist at the Montreal Neurological Institute and Hospital at Mcgill University and senior investigator on the paper. his is especially important with nerve cells in the brain as you only want the brain to make precise
They did so by suspending the animals in a harness then using implants to electrically stimulate neurons in their lower spinal cord.
##This simulates living bodies where neurons sense and deliver stimuli to the muscles and the muscles provide motion.##
possibly even including damaged nerve cells and spinal chord injuries. Via Dvice Share Thissubscribedel. icio. usfacebookredditstumbleupontechnorat t
but within 40 years neurons made from nanomaterials could enable humans to survive even the most horrendous accident,
##Researchers at#USC s Viterbi School of Engineeringhave created a#functioning synapse#using neurons made from carbon nanotubes.
In tests, their synapse circuits perform similar to normal biological neurons. Of course, duplicating synapse firings in nanotube circuits does not mean that scientists are ready to replace the human brain,
but a new interdisciplinary research center at#MIT#aims at nothing less than unraveling the mystery of intelligence;
##The human cortex has about 22 billion neurons and 220 trillion synapses.####Today, computers capable of crunching this amount of data do not exist,
and instructions for nanobots to form new neurons and position them next to existing brain cells to be replaced.
While zinc is more stable, the water-based electrolytes in conventional zinc batteries cause zinc to form dendrites,
#Researchers discover gene that stimulates growth of new brain cells in adults City of Hope researchers have found that over-expressing a specific gene could prompt growth in adults of new neurons in the hippocampus,
and the growth of new neurons or neurogenesis is an important step in developing therapies to address impaired learning
however, scientists have found evidence of neurogenesis in later adulthood occurring mostly in the hippocampus,
Abstract of Proceedings of the National Academy of Sciences paper The role of the nuclear receptor TLX in hippocampal neurogenesis and cognition has begun just to be explored.
Transgenic TLX expression led to mice with enlarged brains with an elongated hippocampal dentate gyrus and increased numbers of newborn neurons.
Specific expression of TLX in adult hippocampal dentate gyrus via lentiviral transduction increased the numbers of Brdu+cells and Brdu+Neun+neurons.
Consistent with increased neurogenesis in the hippocampus the TLX transgenic mice exhibited enhanced cognition with increased learning and memory.
These results suggest a strong association between hippocampal neurogenesis and cognition, as well as significant contributions of TLX to hippocampal neurogenesis, learning,
and memory y
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and strengthen the connections between nerve cells, called synapses. We can form a memory, erase that memory
Analyses showed chemical changes within the optically stimulated nerve synapses, indicative of synaptic strengthening. In the next stage of the experiment, the research team demonstrated the ability to weaken this circuitry by stimulating the same nerves with a memory-erasing, low-frequency train of optical pulses.
or weaken the synapses, said Sadegh Nabavi, a postdoctoral researcher in the Malinow lab and the study s lead author.
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,
the mice got smarter, perhaps due to increased connections between nerve cells. This could provide a promising avenue of research for tackling Alzheimer disease.
the Independent reports that scientists have been able to more effectively shut down the neurons: r Deisseroth team has engineered now re its light-sensitive proteins to switch cells much more adequately than before.
The researchers found that p25 is required for synaptic plasticity, the ability of brain connections to change over time;
especially for the process called long-term depression (LTD) that selectively weakens sets of synapses and is associated with memory extinction.
a graduate student in Patel lab, the researchers also showed for the first time how nerve cells in this part of the brain make
which allowed very detailed visualization at individual synapses, or gaps between nerve cells. e know where the receptors are,
we know their function, we know how these neurons make their own cannabinoids, Patel said. ow can we see how that system is affected by stress and chronic (marijuana) use?
It might fundamentally change our understanding of cellular communication in the amygdala. i
#Millennials see financial institutions as irrelevant Scratch polled 10,000 millennials to find out which industry was most prime for disruption.
"but it can simulate millions of the brain's neurons and perform complex tasks using very little energy.
that is capable of simulating 1 million neurons and 256 million neural connections, or synapses. In addition to mimicking the brain's processing by themselves,
or"axons"(the cablelike part of a nerve cell that transmits electrical signals) and 256 output lines, or"neurons."
the artificial neurons only send signals, or spikes, when electrical charges reach a certain threshold.
A group at Stanford university developed a system called"Neurogrid"that can simulate a million neurons and billions of synapses.
the IBM chip can simulate the same number of neurons with only a single chip,
IBM created the chip as part of DARPA's Synapse program (short for Systems of Neuromorphic Adaptive Plastic Scalable Electronics.
which contains about 86 trillion neurons and 100 trillion synapses.""We've come a long way,
Lein's team saw these genes were turned on in newly generated excitatory neurons (which activate other neurons) in the prenatal cortex suggesting autism may start in the womb as opposed to later in life.
Taken together these brain maps paint a picture of where and when different genes become active in the brain.
The genes encode proteins that perform all the vital tasks inside neurons giving rise to the complex cognition of the human brain.
It is hoped that the cells will lay down sheaths of myelin an insulator essential for conducting nerve impulses around injured neurons,
as well as stimulating nerve cells to regenerate. The cells have demonstrated both capabilities in animals. 1 The company said it expects to begin enrolment early this summer at up to seven US medical centres.
in turn, generate perfectly matched specialized tissues#replacement neurons, say#for cell therapy. Although the number of published papers from ips-cell research has not yet caught up with that of ES-cell work (see Inducing a juggernaut),
which she finds much easier to prompt into neurons than ips cells.""I am excited and relieved by this decision,
And Huganir s mice showed normal levels of long-term potentiation#the strengthening of synapses between two neurons that is thought to underlie learning and memory."
At that point, neurons are still migrating to their final destinations; the first connections between upper brain areas are snapping into place;
The chip helps generate at least partial vision by stimulating intact nerve cells in the retina. The nerve impulses from these cells are led then via the optic nerve to the visual cortex where they create impressions of sight.
The molecules lie on the outer membranes of nerve cells; when drugs or neurotransmitters lock into the receptors from outside the cell,
suggesting that it is not crazy to map every neuron in the brain of an animal.
which contains about 85,000 times more neurons than the zebrafish brain. The resolution offered by the zebrafish study will enable researchers to understand how different regions of the brain work together,
000 neurons at once is difficult, so researchers must pick and choose which to look at, and extrapolate.
The fish's neurons make a protein that fluoresces in response to fluctuations in the concentration of calcium ions,
which occur when nerve cells fire. A microscope sends sheets of light rather than a conventional beam through the fish's brain,
the researchers were able to see populations of neurons in distinct regions that correlated to their activity (see video above).
whether a neuron has fired once or several times in quick succession. But Fetcho says that it is fast enough to start to understand how activity flows through the brain.#"
The processor inside the device amplifies the electrical signals emitted by neurons, then translates the information into digital codes,
and show that electrical signals emitted by neurons inside the cortex could be recorded, then used to steer a wheelchair
#Genetic Brain disorders Converge at the Synapse Several genetic disorders cause intellectual disability and autism. Historically, these genetic brain diseases were viewed as untreatable.
and intellectual disability disrupt protein synthesis at synapses, and that a treatment developed for one disease produced a cognitive benefit in the other.
Bear and others discovered that the loss of this gene results in exaggerated protein synthesis at synapses, the specialized sites of communication between neurons.
Some of the 27 affected genes play a role in protein synthesis regulation, leading Bear and colleagues to wonder if 16p11.2 microdeletion syndrome and fragile X syndrome affect synapses in the same way.
by removing a biochemical lampthat prevents connections between nerve cells in the brain from growing stronger.
A report on the discovery appears Jan 7 in the journal Neuron. Animals learn and form memories
when connections called synapses among brain cells form and grow stronger. Researchers have known long that a crucial step in the process is the flow of calcium ions into the synapse area,
but hat happens next has been a mystery for 25 years, says Rick Huganir, Ph d.,director of the Solomon H. Snyder Department of Neuroscience at the Johns hopkins university School of medicine.
added chemicals to lab-grown neurons to spur them to form stronger connections and saw that at rest,
a protein called Syngap was concentrated in so-called dendritic spines that form synapses with other cells a pattern previous experiments also had identified.
But once the synapse-strengthening process began Syngap flooded out of the dendritic spines. The spines then grew larger,
strengthening the synapses, Huganir says. The research team found that Syngap is clamped usually to the caffoldingthat gives dendritic spines their structure.
An influx of calcium into the synapse activates Camkii, which in turn unhooks Syngap from the cellsscaffolding
Compared to normal neurons, there was less Syngap in synapses when they were at rest, but activating Camkii did not noticeably change anything. his gives us a much clearer idea of how some Syngap mutations cause problems in the brain,
Huganir says. The findings may one day lead to drugs or other interventions that would lessen the effects of the mutations,
made up of two groups of cells known as Agrp and POMC neurons, senses long-term changes in the body hormone and nutrient levels,
and that the activation of Agrp neurons directly drives eating. But the new work shows that the Agrp-POMC circuit responds within seconds to the mere presence of food,
and that Agrp neurons motivate animals to seek and obtain food, rather than directly prompting them to consume it. o one would have predicted this.
and more recently on Agrp and POMC neurons, two small populations of cells within that nucleus. These two groups of cells,
when Agrp neurons are active, POMC neurons are not, and vice versa. Hundreds of experiments in which scientists added hormones or nutrients to brain slices
while recording the activity of Agrp and POMC neurons have laid the foundation of the dominant model of how the hunger circuit works.
As we grow hungry, this view holds, gradual changes in hormone levels send signals that begin to trigger Agrp neurons, the activity
of which eventually drives us to eat. As we become sated, circulating nutrients such as glucose activate POMC neurons,
which suppresses the desire to eat more food. Yiming Chen a graduate student in Knight lab, was expecting to build on the prevailing model of the hunger circuit
when he began experiments using newly developed fiber optic devices that allowed him to record Agrp-POMC activity in real time as mice were given food after a period of fasting. o one had recorded actually the activity of these neurons in a behaving mouse,
and we would see these neurons slowly change their activity, Knight said. hat we found
almost immediately the neurons reversed their activation state. This happens when the mouse first sees
and Agrp neurons again beginning to fire, if the food were taken away. The magnitude of the transition from Agrp to POMC activity was correlated also directly with the palatability of the food offered:
while slow, hunger-induced changes in hormones and nutrients activate Agrp neurons over the long term,
these neurons are inactivated rapidly by the sight and smell of food alone. A major implication of this discovery
is that the function of Agrp neurons is to motivate hungry animals to seek and find food,
The fact that more accessible and more palatable, energy-rich foods engage POMC neurons and shut down Agrp activity more strongly suggests that the circuit also has nticipatoryaspects, by
which these neurons predict the nutritional value of a forthcoming meal and adjust their activity accordingly.
and the desire to seek additional nutrition. volution has made these neurons a key control point in the hunger circuit,
including a large proportion of specialised neurons, some blood vessel cells and glial cells, which take care of waste products,
protect against infection and supply nerve cells with nutrients. With the help of this detailed map, the scientists were able to identify hitherto unknown cell types,
including a nerve cell in the most superficial cortical layer, and six different types of oligodendrocyte,
which are cells that form the electrically insulating myelin sheath around the nerve cells. The new knowledge the project has generated can shed more light on diseases that affect the myelin
such as multiple sclerosis (MS). e could also confirm previous findings, such as that the pyramidal cells of the cerebral cortex are organised functionally in layers,
Nerve cells are approximately 20 micrometres in diameter, glial cells about 10 micrometres. A micrometre is equivalent to a thousandth of a millimetre.
These oligomers are highly toxic to nerve cells and are thought now to be responsible for the devastating effects of Alzheimer disease.
Scientists at The Scripps Research Institute (TSRI) have found diverse genomic changes in single neurons from the brains of Alzheimer s patients pointing to an unexpected factor that may underpin the most common form of the disease.
A new study published February 4 2015 in the online journal elife shows that Alzheimer s brains commonly have many neurons with significantly more DNA and genomic copies of the Alzheimer s-linked gene APP than normal brains.#
#Our findings open a new window into the normal and diseased brain by providing the first evidence that DNA variation in individual neurons could be related to brain function
Next the researchers used a technique called single-cell qpcr to determine the numbers of APP copies in 154 individual neurons from Alzheimer s and normal brains.
They also tested the neurons using a technique called FISH as an independent method to assess APP copies using fluorescent probes.
The tests showed that neurons from patients with sporadic Alzheimer s disease were four times as likely to contain more than the normal two copies of APP with some Alzheimer s neurons containing up to 12 copies of APP a phenomenon never seen in the controls.#
and disease the causes of mosaicism and potential new disease drug targets present in the millions of extra base-pairs found in single Alzheimer s disease neurons.
In addition to Chun Kaeser and Bushman other authors of the study#Genomic mosaicism with increased amyloid precursor protein (APP) gene copy number in single neurons from sporadic Alzheimer s disease brains#were Jurgen
Full open access research for#Genomic mosaicism with increased amyloid precursor protein (APP) gene copy number in single neurons from sporadic Alzheimer s disease brains#by Diane M Bushman
#Previous reports have shown that individual neurons of the brain can display somatic genomic mosaicism of unknown function.
In this study we report altered genomic mosaicism in single sporadic Alzheimer s disease (AD) neurons characterized by increases in DNA content and amyloid precursor protein (APP) gene copy number.
Two independent single-cell copy number analyses identified amplifications at the APP locus. The use of single-cell qpcr identified up to 12 copies of APP in sampled neurons.
These data identify somatic genomic changes in single neurons affecting known and unknown loci which are increased in sporadic AD
repair damaged spinal cords or even connect parts of the brain like an artificial synapse. The key finding is that the sensor
with the idea of establishing a kind of direct wireless connection to neurons. DNEWS: Brain-To-Brain Networking Takes First Baby Stepsthe agnetoelectricnanoparticles (MENS) injected in the mice have several special properties.
Secondly, the particles can be triggered by an outside magnetic field to produce an electric field when adjacent to individual neurons.
Moreover, their brains had fewer new neurons than other mice. Thirty days later, however, when the protein had been cleared from their bodies,
or whether a neuron is active at a certain time. If you could turn the DNA inside a cell into a little memory device on its own
Furthermore the researchers found that they could reverse the emotional association of specific memories by manipulating brain cells with optogenetics a technique that uses light to control neuron activity.
In this study the researchers set out to explore that malleability with an experimental technique they recently devised that allows them to tag neurons that encode a specific memory or engram.
First they used their engram-labeling protocol to tag neurons associated with either a rewarding experience (for male mice socializing with a female mouse) or an unpleasant experience (a mild electrical shock.
and the critical underlying biological processes such as an impaired ability of neurons to communicate with each other.
and comprehensively measure the dynamic activity of genes in living cells including lab-grown neurons produced by new stem-cell technologies.
#Noninvasive brain control Optogenetics, a technology that allows scientists to control brain activity by shining light on neurons,
MIT engineers have developed now the first light-sensitive molecule that enables neurons to be silenced noninvasively, using a light source outside the skull.
has become a common laboratory tool for shutting off or stimulating specific types of neurons in the brain,
The neurons to be studied must be engineered genetically to produce light-sensitive proteins known as opsins, which are channels
such as an optical fiber, into the brain to control the selected neurons. Such implants can be difficult to insert,
these molecules, found in the bacteria Haloarcula marismortui and Haloarcula vallismortis, did not induce a strong enough photocurrent an electric current in response to light to be useful in controlling neuron activity.
which could be controlled by shutting off misfiring neurons that cause seizures, Boyden says. ince these molecules come from species other than humans,
#Illuminating neuron activity in 3-D Researchers at MIT and the University of Vienna have created an imaging system that reveals neural activity throughout the brains of living animals.
The team used the new system to simultaneously image the activity of every neuron in the worm Caenorhabditis elegans,
as well as the entire brain of a zebrafish larva, offering a more complete picture of nervous system activity than has been previously possible. ooking at the activity of just one neuron in the brain doesn tell you how that information is being computed;
for that, you need to know what upstream neurons are doing. And to understand what the activity of a given neuron means,
you have to be able to see what downstream neurons are doing, says Ed Boyden, an associate professor of biological engineering and brain and cognitive sciences at MIT and one of the leaders of the research team. n short,
if you want to understand how information is being integrated from sensation all the way to action, you have to see the entire brain.
High-speed 3-D imaging Neurons encode information sensory data motor plans, emotional states, and thoughts using electrical impulses called action potentials,
scientists can visualize this electrical firing of neurons. However, until now there has been no way to image this neural activity over a large volume, in three dimensions,
Neurons in action The researchers used this technique to image neural activity in the worm C. elegans, the only organism for
This 1-millimeter worm has 302 neurons, each of which the researchers imaged as the worm performed natural behaviors, such as crawling.
The current resolution is high enough to see activity of individual neurons but the researchers are now working on improving it so the microscope could also be used to image parts of neurons,
such as the long dendrites that branch out from neuronsmain bodies. They also hope to speed up the computing process,
which currently takes a few minutes to analyze one second of imaging data. The researchers also plan to combine this technique with optogenetics,
By stimulating a neuron with light and observing the results elsewhere in the brain, scientists could determine which neurons are participating in particular tasks.
Other co-authors at MIT include Nikita Pak, a Phd student in mechanical engineering, and Gordon Wetzstein, a research scientist at the Media Lab. The work at MIT was funded by the Allen Institute for Brain science;
the national BRAIN INITIATIVE aims to revolutionize our understanding of cognition by mapping the activity of every neuron in the human brain,
Tracking dopamine Dopamine is one of many neurotransmitters that help neurons to communicate with each other over short distances.
#Seeking a parts list for the retina New technique classifies retinal neurons into 15 categories,
many types of neurons in our retinas interact to analyze different aspects of what we see
Neuroscientists believe there are 20 to 30 types of these specialized neurons, known as retinal ganglion cells,
Using a computer algorithm that traces the shapes of neurons and groups them based on structural similarity,
the researchers sorted more than 350 mouse retinal neurons into 15 types, including six that were unidentified previously.
This technique, described in the March 24 online edition of Nature Communications, could also be deployed to help identify the huge array of neurons found in the brain cortex,
which relay visual input through several layers of neurons in the retina. The final layer is composed of ganglion cells,
which aimed to create a system that would accurately classify known neurons and also assign unknown neurons to the correct groups.
To begin the researchers used a light microscope to image individual neurons in the brains of mice that had been engineered genetically so that one class of ganglions,
such as the J cell, is tagged with a fluorescent protein. They also obtained images of unidentified neurons using mice genetically engineered
so that only a few of their ganglion neurons fluoresce. In total, the researchers imaged 363 cells 111 that were known genetically
and 252 that were selected randomly. Using a computer algorithm, they traced along the many branches, known as dendrites,
that extend from each cell to connect with other cells. These dendrites form clusters called arbors
which were the key to the researchersclassification system. After each neuron arbor was diagrammed, the researchers used a computer program to align
and condense each one so that the arbors were represented by smaller, but still distinctive, shapes. By comparing these shapes,
the computer program correctly classified all of the known neurons. Among the randomly selected neurons, some ended up being grouped with the known types,
while others formed six new clusters yet to be identified. This approach is an important contribution to efforts to create a arts listfor the retina,
each neuron dendrites travel to other layers to interact with other cells. This stratification is very specific to each cell type,
ensuring that the neurons are communicating with the correct partners as they relay visual information.
The researchers believe there may be still more types of neurons that did not appear in their data set
In future work, they hope to examine larger sets of neurons in hopes of finding some of these other neuron types.
They also hope to use their technique to study parts of the brain that have many layers of neurons especially the neocortex
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