Neuron

Axon (111)
Dendrite (77)
Interneuron (10)
Motor neuron (37)
Neurogenesis (11)
Neuron (1102)
Synapse (106)

Synopsis: Domenii: Neuroscience: Neuroscience generale: Nervous system: Neuron: Neuron:

either boost or curb levels of circulating neurotransmitters, the chemicals that relay signals between nerve cells in the brain.

In the case of scent receptors, specialised neurons send messages to the brain so we know what we have sniffed.

no one had been able to isolate the specific types of nerve cells in the TRN from others nearby,

when a cellular receptor called Erbb4 was repressed experimentally in certain neurons of the TRN. They learned that the ability of the mice to switch attention between conflicting sensory cues was impaired.

"highly sensitive whole-genome sequencing of single neurons and a new technology that identifies inserted bits of DNA caused by retrotransposons,

"There is a lot of genetic diversity from one neuron to the other, and this work gets at how somatic mutations are distributed in the brain,

which developed methods to sequence the genomes of single neurons, and represents the first time single neurons have been sequenced in their entirety.

The single-cell technique is better at detecting subtle mosaicism than usual DNA sequencing methods,

study published by Walsh's lab in 2014 used single-neuron sequencing to detect copy number variants--another type of mutation affecting the number of copies of chromosomes or chromosome fragments.

Parkinson disease is characterized by impairment or deterioration of neurons in an area of the brain known as the substantia nigra In the familial form of the disorder,

Researchers found that asyn contacting the neuron membrane in that site immediately and deeply penetrated it,

such as neurons firing in the rodent brain, crawling fruit fly larvae, and single cells in the zebrafish heart while the heart is actually beating spontaneously--this has not been possible until now."

even delivering neurons that flash as they fire in the living brain. Yet imaging techniques that can capture these dizzying dynamic processes have lagged behind.

acquiring enough of these layers to form a 3d image at fast enough rates to capture events like neurons actually firing has become a frustrating road-block.

and read by the electrodes. s soon as we have understood the electroencephalography patterns produced by the groups of neurons in the brain,

and also prevent the loss of neurons, says Gómez-Nicola. e selectively targeted the CSF1R with a small-molecule inhibitor delivered systemically,

"Cells that divide have different functions and shapes muscle cells, neuron cells and so on. When they divide they pass on their DNA,

They kept track of the energy required to run a nerve cell and kept count of the ions passing into and out of the cells.

They were motivated by previous Penn State experiments that showed the very sensitive link between oxygen concentration with reliable and rapid changes in nerve cell behavior.

and spreading depression were all part of a spectrum of nerve cell behavior. It appeared that decades of observations of different phenomena in the brain could share a common underlying link.

#Team makes spiny neurons without stem cells Washington University in St louis rightoriginal Studyposted by Julia Evangelou Strait-WUSTL on October 30 2014scientists have figured outâ#howâ#to convert human skin cells

##The investigators produced a specific type of brain cell called medium spiny neurons which are important for controlling movement.

They knew from past work that exposure to two small molecules of RNA a close chemical cousin of DNA could turn skin cells into a mix of different types of neurons.

Though the investigators still are unraveling the details of this complex process these micrornas appear to be opening up the tightly packaged sections of DNA important for brain cells allowing expression of genes governing development and function of neurons.

Knowing exposure to these micrornas alone could change skin cells into a mix of neurons the researchers then started to fine tune the chemical signals exposing the cells to additional molecules called transcription factors that they knew were present in the part of the brain where medium spiny

neurons are common.####We think that the micrornas are really doing the heavy lifting##says co-first author Matheus B. Victor a graduate student in neuroscience.##

##They are priming the skin cells to become neurons. The transcription factors we add then guide the skin cells to become a specific subtype in this case medium spiny neurons.

We think we could produce different types of neurons by switching out different transcription factors.####Yoo also explains that the micrornas

but not the transcription factors are important components for the general reprogramming of human skin cells directly to neurons.

His team including co-first author Michelle C. Richner senior research technician showed that when the skin cells were exposed to the transcription factors alone without the micrornas the conversion into neurons wasn t successful.

The researchers performed extensive tests to demonstrate that these newly converted brain cells did indeed look

and behave like native medium spiny neurons. The converted cells expressed genes specific to native human medium spiny neurons and did not express genes for other types of neurons.

When transplanted into the mouse brain the converted cells showed morphological and functional properties similar to native neurons.

To study the cellular properties associated with the disease the investigators now are taking skin cells from patients with Huntington s disease

and reprogramming them into medium spiny neurons using the approach described in the new paper.

The work appears in the journal Neuron. Funding came from a National Science Foundation Graduate Research fellowship a fellowship from Cognitive Computation and Systems neuroscience Pathway grants from the National institutes of health and awards from the Mallinckrodt Jr.

and nerve cells the researchers demonstrate. This special type of connection called a ribbon synapse allows extra-rapid communication of signals that travel back and forth across tiny gaps between the two types of cells.##

and insert the needle used to destroy the misbehaving neurons through the top of the head.

because it makes the neurons in this part of the brain sensitive to glucose. The neurons sense the increase in glucose levels

and then tell the pancreas to release insulin, which is the hormone that maintains a steady level of glucose in the blood,

the neurons were no longer sensitive to increased glucose levels and could not control the release of insulin from the pancreas,

Diano says the next step in this research is to identify the targets of this enzyme by understanding how the enzyme makes the neurons sense changes in glucose levels. f we succeed in doing this

but can visualize individual vessels or groups of neurons. The first step of the new technique, called near infrared-IIA imaging,

Hong says. e could also label different neuron types in the brain with biomarkers and use this to monitor how each neuron performs.

Eventually we might be able to use NIR-IIA to learn how each neuron functions inside of the brain.

Other coauthors of the study are from Stanford, Massachusetts General Hospital, and Harvard Medical school a

For example, the neurons of the peripheral nervous system could be mapped throughout a whole body, as could the distribution of viruses, such as HIV, in an animal model.

including activity of neurons, blood vessels, the respiratory tract, and bladder. The alcohol-insensitive mutation does not disrupt these functions at all. e got pretty lucky and found a way to make the channel insensitive to alcohol without affecting its normal function,

what you see is the fatty outer covering of the nerve cells within, which blocks microscopes from taking images of the intricate connections between deep brain cells.

##In that early developmental gestational period the brain is developing synapses the spaces between neurons where electrical impulses are turned into neurotransmitting chemicals that leap from one neuron to another to pass messages along##Â#Hertz

#These neurons order stem cells to crank out new neurons Is it possible that your brain can repair itself from within?

The discovery of a new type of neuron that tells stem cells to make new neurons opens that tantalizing possibility.

Neuroscientists have suspected for some time that the brain has some capacity to direct the manufacturing of new neurons,

In a study with mice, his team found a previously unknown population of neurons within the subventricular zone (SVZ) neurogenic niche of the adult brain, adjacent to the striatum.

These neurons expressed the choline acetyltransferase (Chat) enzyme which is required to make the neurotransmitter acetylcholine.

With optogenetic tools that allowed the team to tune the firing frequency of these Chat+neurons up and down with laser light,

REGIONS OF THE HUMAN BRAIN The mature Chat+neuron population is just one part of an undescribed neural circuit that apparently talks to stem cells

and tells them to increase new neuron production, Kuo says. Researchers don know all the parts of the circuit yet

but by controlling Chat+neuronssignals Kuo and his colleagues have established that these neurons are necessary and sufficient to control the production of new neurons from the SVZ niche. e have been working to determine how neurogenesis is sustained in the adult brain.

a neural circuit that can directly instruct the stem cells to make more immature neurons,

The young neurons produced by these signals were destined for the olfactory bulb in rodents, as the mouse has a large amount of its brain devoted to process the sense of smell and needs these new neurons to support learning.

But in humans, with a much less impressive olfactory bulb, Kuo says it possible new neurons are produced for other brain regions.

One such region may be the striatum which mediates motor and cognitive controls between the cortex

Postdoctoral fellow Brent Asrican made a key observation that orders from the novel Chat+neurons were heard clearly by SVZ stem cells.

And just last month in the journal Cell, a Swedish team observed newly made control neurons called interneurons in the human striatum for the first time.

The questions ahead are both upstream from the new Chat+neurons and downstream, Kuo says.

Upstream, what brain signals tell Chat+neurons to start asking the stem cells for more young neurons?

and these chemicals cause pain by acting on an equally diverse group of receptors on the surface of pain-sensing neurons. big problem in our field is that it is impractical to block each of these receptors with a mixture of drugs,

how do we alter PIP2 levels in the neurons that sense pain? Zylka says. f we could lower the level of PIP2,

The researchers then used a mouse model to show that PIP5K1C was responsible for generating at least half of all PIP2 in these neurons.

Wright is first author of the paper that is published in the journal Neuron. hat told us that a 50 percent reduction in the levels of PIP5K1C was sufficient to reduce PIP2 levels in the tissue we were interested inhere pain-sensing neurons are located,

softer micropost carpets turned into nerve cells much faster and more often than those they grew on the stiffer surfaces.

After 23 days, the colonies of spinal cord cellsotor neurons that control how muscles movehat grew on the softer micropost carpets were four times more pure and 10 times larger than those growing on either traditional plates

Researchers like Feldman believe stem cell therapiesoth from embryonic and adult varietiesight help patients grow new nerve cells.

She using Fu technique to try to make fresh neurons from patientsown cells. At this point, theye examining how

The researchers verified that the new motor neurons they obtained on soft micropost carpets showed electrical behaviors comparable to those of neurons in the human body.

a process where nerve cells become specialized for their specific functions based on their physical location in the body,

Working with mice that mimic schizophrenia and related disorders, the researchers were able to partially restore disabled neurons

so they could connect to other nerve cells. The findings in adolescent mice are an especially promising step in efforts to develop better therapies for schizophrenia in humans,

as it is called, makes a protein that appears to regulate neurons in the cerebral cortex responsible for igher-orderfunctions, like information processing.

In studies of rodent brain cells, the researchers found that a DISC1 deficit caused deterioration of vital parts of the neuron called spines

which help neurons communicate with one another. Reduced amounts of DISC1 protein also impact the development of a protein called Kalirin-7 (KAL7),

and ultimately turned them into neurons. The team then compared those neurons to cells taken from people without bipolar.

The comparison revealed very specific differences in how these neurons behave and communicate with each other,

and identified striking differences in how the neurons respond to lithium, the most common treatment for bipolar disorder.

The team used a type of stem cell called induced pluripotent stem cells, or ipscs.

With further coaxing, the cells became neurons. his gives us a model that we can use to examine how cells behave as they develop into neurons.

how they differentiate into neurons, how they communicate, and how they respond to lithium, says Sue Ohea,

WHAT DIFFERENT ABOUT BIPOLAR NEURONS? The skin samples were used to derive the 42 ipsc lines.

and then reevaluated the cells once they had become neurons, very specific differences emerged between the cells derived from bipolar disorder patients and those without the condition.

Specifically, the bipolar neurons expressed more genes for membrane receptors and ion channels than non-bipolar cells,

Calcium signals are known already to be crucial to neuron development and function. So the new findings support the idea that genetic differences expressed early during brain development may have a lot to do with the development of bipolar disorder symptomsnd other mental health conditions that arise later in life, especially in the teen and young adult years.

the neurons made from bipolar disorder patients also differed in how they were ddressedduring development for delivery to certain areas of the brain.

and obtain mature neurons that can be studied. They will share their cell lines with other researchers via the Prechter Repository.

#Tarantula venom probe shows neurons in action University of California Davis rightoriginal Studyposted by Carole Gan-UC Davis on October 24 2014a cellular probe that combines a tarantula toxin

with a fluorescent compound can help scientists observe electrical activity in neurons and other cells.

They perform a critical function generating an electrical current in neurons muscles and other cells.

These channels are expressed in most if not all neurons yet their regulation and activity are complex

so that when nerve cells are activated they both fluoresce green and express a protein that allows the cells to be switched off by light.

which nerve cells in the cortex and hippocampus were activated in learning and memory retrieval and switch them off with light directed through a fiber-optic cable.

By switching off the specific nerve cells in the hippocampus they showed that the mice lost their memories of the unpleasant event.

The findings are published in the journal Neuron. Grants from the Whitehall Foundation Mcknight Foundation Nakajima Foundation and the National Science Foundation funded the work.

#Scientists use light to make mice asocial California Institute of technology rightoriginal Studyposted by Jessica Stoller-Conrad-Caltech on September 19 2014scientists have discovered antagonistic neuron populations in the mouse amygdala that control

but distinct populations of neurons in the amygdala a part of the brain that is involved in innate social behaviors.

Interestingly these two populations are distinguished according to the most fundamental subdivision of neuron subtypes in the brain:

the ocial neuronsare inhibitory neurons (which release the neurotransmitter GABA or gamma aminobutyric-acid acid) while the elf-grooming neuronsare excitatory neurons

In optogenetics neurons are altered genetically so that they express light-sensitive proteins from microbial organisms. Then by shining a light on these modified neurons via a tiny fiber optic cable inserted into the brain researchers can control the activity of the cells as well as their associated behaviors.

Using this optogenetic approach Anderson s team was able to selectively switch on the neurons associated with social behaviors

and those linked with asocial behaviors. With the social neurons the behavior that was elicited depended upon the intensity of the light signal.

That is when high-intensity light was used the mice became aggressive in the presence of an intruder mouse.

When the neurons associated with asocial behavior were turned on the mouse began self-grooming behaviors such as paw licking

The researchers could also use the light-activated neurons to stop the mice from engaging in particular behaviors.

For example if a lone mouse began spontaneously self-grooming the researchers could halt this behavior through the optogenetic activation of the social neurons.

Surprisingly these two groups of neurons appear to interfere with each other s function: the activation of social neurons inhibits self-grooming behavior

while the activation of self-grooming neurons inhibits social behavior. Thus these two groups of neurons seem to function like a seesaw one that controls

whether mice interact with others or instead focus on themselves. It was unexpected completely that the two groups of neurons could be distinguished by

whether they were excitatory or inhibitory. f there was ever an experiment that carves nature at its joints'says Anderson his is it. his seesaw circuit Anderson

and his colleagues say may have some relevance to human behavioral disorders such as autism. n autismanderson says here is a decrease in social interactions

or self-oriented behaviors#a phenomenon known as perseveration. ere by stimulating a particular set of neurons we are both inhibiting social interactions

but if you found the right population of neurons it might be possible to override the genetic component of a behavioral disorder like autism by just changing the activity of the circuits#tipping the balance of the seesaw in the other directionhe says.

#Neurons reveal the brain s learning limit Scientists have discovered a fundamental constraint in the brain that may explain why it s easier to learn a skill that s related to an ability you already have.

Because the existing brain patterns likely reflect how the neurons are interconnected the results suggest that the connectivity among neurons shapes learning. e wanted to study how the brain changes its activity

but can t visualize individual vessels or groups of neurons. The first step of the new technique called near infrared-IIA imaging

NIR-IIA imaging might offer a means of better understanding the role of healthy vasculature in those diseases Hong says. e could also label different neuron types in the brain with biomarkers

and use this to monitor how each neuron performs. Eventually we might be able to use NIR-IIA to learn how each neuron functions inside of the brain. ther coauthors of the study are from Stanford Massachusetts General Hospital and Harvard Medical school.

Source: Stanford Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license

For example the neurons of the peripheral nervous system could be mapped throughout a whole body as could the distribution of viruses such as HIV in an animal model.

Together these 16 chips can simulate 1 million neurons and billions of synaptic connections. The team designed these chips with power efficiency in mind.

It about the size of an ipad and can simulate many more neurons and synapses than other brain mimicking devices using only about the power it takes to run a tablet computer.

with 80,000 times more neurons than Neurogrid, consumes only three times as much power, explains Boahen. chieving this level of energy efficiency

and neurons to able to use one of these. OTHER ATTEMPTS TO MIMIC THE BRAIN In an article published in the Proceedings of the IEEE,

or even millions of neurons in the brain as well as write in complex patterns of activity.

to emulate the ability of neurons to make a great many synaptic connections feature that helps the brain solve problems on the fly.

At present a Golden gate chip consists of 256 digital neurons each equipped with 1, 024 digital synaptic circuits,

with IBM on track to greatly increase the numbers of neurons in the system. HICANN CHIP FOR BRAIN SIMULATORS Heidelberg University Brainscales project has the ambitious goal of developing analog chips to mimic the behaviors of neurons and synapses.

Their HICANN chiphort for High Input Count Analog Neural Networkould be the core of a system designed to accelerate brain simulations

At present, the HICANN system can emulate 512 neurons each equipped with 224 synaptic circuits, with a roadmap to greatly expand that hardware base.

how many neurons it simulates and the power it consumes. Neurogrid was by far the most cost-effective way to simulate neurons,

in keeping with Boahen goal of creating a system affordable enough to be used widely in research.

Each of the current million-neuron Neurogrid circuit boards cost about $40 000. Boahen believes dramatic cost reductions are possible.

of which supports 65,536 neurons. Those chips were made using 15-year-old fabrication technologies. By switching to modern manufacturing processes

he could cut a Neurocore cost 100-folduggesting a million-neuron board for $400 a copy.

#Dendrites are like minicomputers in your brain University of North carolina at Chapel hill rightoriginal Studyposted by Mark Derewicz-UNC on October 30 2013the branch-like projections of neurons called dendrites are not just passive wiring

The implications are exciting to think about. xons are where neurons conventionally generate electrical spikes but many of the same molecules that support axonal spikes are also present in the dendrites.

To provide visual evidence of their finding Smith s team filled neurons with calcium dye which provided an optical readout of spiking.

while other parts of the neuron did not meaning that the spikes were the result of local processing within the dendrites.

Study co-author Tiago Branco created a biophysical mathematical model of neurons and found that known mechanisms could support the dendritic spiking recorded electrically further validating the interpretation of the data. ll pointed the data to the same conclusionsmith says. he dendrites are not passive integrators of sensory-driven input;

#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

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,

##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.

#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

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.

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