#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
For example the Kv2. 1 channel that this probe binds to leads to epilepsy when it s not functioning properly. n addition the ability to better observe electrical signaling could help researchers map the brain at its most basic levels. nderstanding the molecular
mechanisms of neuronal firing is a fundamental problem in unraveling the complexities of brain functioncohen says.
The NIH and the Milton L. Shifman Endowed Scholarship for the Neurobiology Course at Woods Hole supported the project.
#Light makes mice forget scary memories University of California Davis rightoriginal Studyposted by Andy Fell-UC Davis on October 14 2014to test a longstanding idea about how the brain retrieves memories about specific places
and the hippocampus reproduces this pattern of activity during retrieval allowing you to re-experience the eventsays Brian Wiltgen of the University of California Davis
. If the hippocampus is damaged patients can lose decades of memories. Normally mice placed in a new environment will nose around
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.
They followed fibers from the hippocampus to specific cells in the cortex and showed that turning off other cells in the hippocampus did not affect retrieval of that memory. he cortex can t do it alone it needs input from the hippocampuswiltgen says. his has been a fundamental assumption in our field for a long time
and the data provides the first direct evidence that it is true. hey could also see how the specific cells in the cortex were connected to the amygdala a structure in the brain that is involved in emotion
and in generating the freezing response. 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.
Source: UC Davisyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
#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
Autism has also been linked to dysfunction of the amygdala a brain structure involved in processing emotions.
In this study we wanted to figure out how the brain does thatanderson says. Anderson and his colleagues discovered two intermingled
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
(which release the neurotransmitter glutamate an amino acid). To study the relationship between these two cell types
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
However the current study helps to provide a needed link between gene activity brain activity and social behaviors nd if you don t understand the circuitry you are never going to understand how the gene mutation affects the behavior. oing forward he says such a complete understanding will be necessary for the development of future therapies.
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.
As reported in Nature the researchers found for the first time that there are limitations on how adaptable the brain is during learning
Understanding how the brain s activity can be lexedduring learning could eventually be used to develop better treatments for stroke and other brain injuries.
and cookies but it would be difficult to make hamburger patties with the existing ingredientssadtler says. e found that the brain works in a similar way during learning.
or the study the research team trained animals (Rhesus macaques) to use a brain-computer interface (BCI) similar to ones that have shown recent promise in clinical trials for assisting quadriplegics
and amputees his evolving technology is a powerful tool for brain researchsays Daofen Chen program director at the National Institute of Neurological disorders
and Stroke (NINDS) part of the National institutes of health. t helps scientists study the dynamics of brain circuits that may explain the neural basis of learning. he researchers recorded neural activity in the subject s motor cortex
which required them to generate the patterns of neural activity that the experimenters had requested. If the subjects could move the cursor well that meant that they had learned to generate the neural activity pattern that the researchers had specified.
The results showed that the subjects learned to generate some neural activity patterns more easily than others
since they only sometimes achieved accurate cursor movements. The harder-to-learn patterns were different from any of the preexisting patterns
whereas the easier-to-learn patterns were combinations of preexisting brain patterns. 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
when you learn and also how its activity cannot change. Cognitive flexibility has a limit
for novel rehabilitation procedures for the many neural disorders that are characterized by improper neural activityyu says. estoring function might require a person to generate a new pattern of neural activity.
what were used in this study to coach patients to generate proper neural activity. he researchers are part of the Center for the Neural Basis of Cognition (CNBC) a joint program between Carnegie mellon University and the University of Pittsburgh.
Lead researcher Kaye Morgan from Monash University says the imaging method allows doctors to look at soft tissue structures for example the brain airways
The new imaging method which was developed using a synchrotron x-ray source may also open up possibilities in assessing how effective treatments were for other lung heart and brain diseases.
Our brains are able to judge the trustworthiness of a face even when we cannot consciously see it. he results are consistent with an extensive body of research suggesting that we form spontaneous judgments of other people that can be largely outside awarenessexplains Jonathan Freeman an assistant professor in New york University's psychology department.
The researchers focused on the workings of the brain's amygdala a structure that is important for humans social and emotional behavior.
if the amygdala is capable of responding to a complex social signal like a face's trustworthiness without that signal reaching perceptual awareness.
To gauge this part of the brain's role in making such assessments the study s authors conducted a pair of experiments in which they monitored the activity of subjects amygdala
Their findings appear in the Journal of Neuroscience. These images included both standardized photographs of actual strangers faces as well as artificially generated faces
In the experiments a new set of subjects viewed the same faces inside a brain scanner
which is thought to terminate the brain's ability to further process the face and prevent it from reaching awareness.
In the first experiment the researchers examined amygdala activity in response to three levels of a face's trustworthiness:
In the second experiment they assessed amygdala activity in response to a fully continuous spectrum of trustworthiness.
Across the two experiments the researchers found that specific regions inside the amygdala exhibited activity tracking how untrustworthy a face appeared
and other regions inside the amygdala exhibited activity tracking the overall strength of the trustworthiness signal
(whether untrustworthy or trustworthy) even though subjects could not consciously see any of the faces. hese findings provide evidence that the amygdala's processing of social cues in the absence of awareness may be more extensive than previously understoodobserves Freeman who as lead author conducted the study as a faculty member at Dartmouth
#See into living brain with lasers and nanotubes Stanford university rightoriginal Studyposted by Bjorn Carey-Stanford on August 7 2014by injecting carbon nanotubes into the bloodstream scientists can use near-infrared lasers to see blood flow in a living animal s brain.
The new technique which is almost completely noninvasive was developed for mice but could offer insight into human ailments such as strokes migraines and possibly Alzheimer s and Parkinson s diseases.
Some of the most damaging brain diseases can be traced to irregular blood delivery in the brain.
or activity of the brain or even stimulate an immune response. Meanwhile noninvasive techniques such as CT SCANS or MRI visualize function best at the whole-organ level
but can t visualize individual vessels or groups of neurons. The first step of the new technique called near infrared-IIA imaging
Furthermore it does not appear to have any adverse affect on innate brain functions. he NIR-IIA light can pass through intact scalp skin
and skull and penetrate millimeters into the brain allowing us to see vasculature in an almost noninvasive waysays first author Guosong Hong who conducted the research as a graduate student in Dai s lab
First the light penetration depth needs to be increased to pass deep into the human brain. Second injecting carbon nanotubes needs approval for clinical application;
#or be caused in part by#changes in blood flow to certain parts of the brain.
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 bio-markers
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
if you look to map long axons or sparse cell populations such as stem cells or tumor cellsshe says.
and her collaborators to create a transparent whole-brain specimen. With the CLARITY method a rodent brain is infused with a solution of lipid-dissolving detergents
and hydrogel#a water-based polymer gel that provides structural support #thus learingthe tissue but leaving its three-dimensional architecture intact for study.
so that it can be used to clear other organs besides the brain and even whole organisms.
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.
or fine axons you want to see#without slicing and realigning individual sections#it frees up the time of the researcher.
a cranial volume reported as only 380 milliliters (23.2 cubic inches) suggesting a brain less than one third the size of an average modern human s and short thighbones
Here too the brain size they estimate is within the range expected for an Australomelanesian human with Down syndrome.
#EEG reveals image in short-term memory Researchers have tapped the rhythm of memories as they occur in near real time in the human brain.
a team led by University of Oregon psychology doctoral student David E. Anderson captured synchronized neural activity while they held a simple oriented bar located within a circle in short-term memory.
and use that brain activity to predict which individuals could store memories with the highest quality or precision.
Although past research has decoded thoughts via brain activity standard approaches are limited expensive and in their ability to track fast-moving mental representations,
says Edward Awh, a professor in the department of psychology and Institute of Neuroscience. The new findings show that EEG measures of synchronized neural activity can precisely track the contents of memory at almost the speed of thought,
he says. hese findings provide strong evidence that these electrical oscillations in the alpha frequency band play a key role in a person ability to store a limited number of items in working memory,
BRAIN STORAGE The findings come from a basic research project led by Awh and coauthor Edward K. Vogel that seeks to understand the limits of storing information. t turns out that it quite restricted,
has established that brain activity can track the content of memory. EEG, however, provides a much less expensive approach
It should provide us with new insights into how rhythmic brain activity supports core memory processes.
#eurogrid chips mimic the brain to use less energy Compared to the human brain, today computers are ridiculously slow
the brain is hard to match, says Kwabena Boahen, associate professor of bioengineering at Stanford university. Boahen and his team have developed a circuit board consisting of 16 custom-designed eurocorechips.
Together these 16 chips can simulate 1 million neurons and billions of synaptic connections. The team designed these chips with power efficiency in mind.
Their strategy was to enable certain synapses to share hardware circuits. The result was called a device Neurogrid.
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.
But it still a power hog compared to the brain. he human brain, with 80,000 times more neurons than Neurogrid, consumes only three times as much power,
explains Boahen. chieving this level of energy efficiency while offering greater configurability and scale is the ultimate challenge neuromorphic engineers face.
Comparison aside, Neurogrid speed and low power characteristics make it ideal for more than just modeling the human brain.
Boahen is working with other Stanford scientists to develop prosthetic limbs for paralyzed people that would be controlled by a Neurocore-like chip. ight now
you have to know how the brain works to program one of these, says Boahen, gesturing at the $40,
000 prototype board on the desk of his office. e want to create a neurocompiler so that you would not need to know anything about synapses
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,
Boahen offers an overview of other ongoing neuromorphic research efforts, including the European union Human brain Project,
which aims to simulate a human brain on a supercomputer. By contrast the US BRAIN Projecthort for Brain Research through Advancing Innovative Neurotechnologiesas taken a tool-building approach by challenging scientists to develop new kinds of tools that can read out the activity of thousands
or even millions of neurons in the brain as well as write in complex patterns of activity.
Zooming from the big picture, Boahen article focuses on two projects comparable to Neurogrid that attempt to model brain functions in silicon and/or software.
IBM OLDEN GATECHIP One of these efforts is IBM Synapse Projecthort for Systems of Neuromorphic Adaptive Plastic Scalable Electronics.
As the name implies Synapse involves a bid to redesign chips, code-named Golden gate, 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
to enable researchers to model drug interactions that might take months to play out in a compressed time frame.
At present, the HICANN system can emulate 512 neurons each equipped with 224 synaptic circuits, with a roadmap to greatly expand that hardware base.
Each of these research teams has made different technical choices, such as whether to dedicate each hardware circuit to modeling a single neural element (e g.,
, a single synapse) or several (e g.,, by activating the hardware circuit twice to model the effect of two active synapses.
These choices have resulted in different trade-offs in terms of capability and performance. In his analysis, Boahen creates a single metric to account for total system costncluding the size of the chip,
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.
LOWER COST FROM $40, 000 TO $400 But much work lies ahead. Each of the current million-neuron Neurogrid circuit boards cost about $40
000. Boahen believes dramatic cost reductions are possible. Neurogrid is based on 16 Neurocores, each of which supports 65,536 neurons.
Those chips were made using 15-year-old fabrication technologies. By switching to modern manufacturing processes
and fabricating the chips in large volumes, he could cut a Neurocore cost 100-folduggesting a million-neuron board for $400 a copy.
With that cheaper hardware and compiler software to make it easy to configure, these neuromorphic systems could find numerous applications.
For instance, a chip as fast and efficient as the human brain could drive prosthetic limbs with the speed
and complexity of our own actionsut without being tethered to a power source. The National institutes of health is funding the project a
#Small tuning fork lets device find greenhouse gas Scientists have created a highly sensitive portable sensor to test the air for the most damaging greenhouse gases.
The device uses a thumbnail-sized quantum cascade laser (QCL) as well as tuning forks that cost no more than a dime to detect very small amounts of nitrous oxide and methane.
#This gene helps some of us never forget a face Emory University rightoriginal Studyposted by Lisa Newbern-Emory on December 24 2013the oxytocin receptor a gene known to influence mother-infant bonding also plays a role in the ability to remember faces.
According to study author Larry Young of the department of psychiatry at Emory University this is the first study to demonstrate that variation in the oxytocin receptor gene influences face recognition skills.
He and colleagues point out the implication that oxytocin plays an important role in promoting our ability to recognize one another yet about one-third of the population possesses only the genetic variant that negatively impacts that ability.
Researchers had previously found the oxytocin receptor is essential for olfactory-based social recognition in rodents like mice
They examined the influence of subtle differences in oxytocin receptor gene structure on face memory competence in the parents non-autistic siblings
and autistic child and discovered a single change in the DNA of the oxytocin receptor had a big impact on face memory skills in the families.
This finding implies that oxytocin likely plays an important role more generally in social information processing
Skuse credits Youngâ#previous research that found mice with a mutated oxytocin receptor failed to recognize mice they previously encountered. his led us to pursue more information about facial recognition and the implications for disorders in
Approximate computing could endow computers with a capability similar to the human brain s ability to scale the degree of accuracy needed for a given task.
and out of cellssays Sebastien Perrier professor at the University of Warwick. uch of this work is done by channel proteins for example in our nervous system where they modulate electrical signals by gating the flow of ions across the cell membranehe says.
#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
but act more like tiny computers multiplying the brain s processing power. uddenly it s
as if the processing power of the brain is much greater than we had originally thoughtsays Spencer Smith an assistant professor in the University of North carolina at Chapel hill s School of medicine.
His team s findings published in the journal Nature could change the way scientists think about longstanding scientific models of how neural circuitry functions in the brain
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.
Previous research using dissected brain tissue had demonstrated that dendrites can use those molecules to generate electrical spikes themselves
but it was unclear whether normal brain activity involved those dendritic spikes. For example could dendritic spikes be involved in how we see?
The answer Smith s team found is yes. Dendrites effectively act as mini-neural computers actively processing neuronal input signals themselves.
Directly demonstrating this required a series of intricate experiments that took years and spanned two continents beginning in senior author Michael Hausser s lab at University college London
They used patch-clamp electrophysiology to attach a microscopic glass pipette electrode filled with a physiological solution to a neuronal dendrite in the brain of a mouse.
The idea was to directly istenin on the electrical signaling process. ttaching the pipette to a dendrite is tremendously technically challengingsmith says. ou can t approach the dendrite from any direction.
And you can t see the dendrite. So you have to do this blind. t s like fishing
Once the pipette was attached to a dendrite Smith s team took electrical recordings from individual dendrites within the brains of anesthetized and awake mice.
As the mice viewed visual stimuli on a computer screen the researchers saw an unusual pattern of electrical signalsâ##bursts of spikesâ##in the dendrite.
Smith s team then found that the dendritic spikes occurred selectively depending on the visual stimulus indicating that the dendrites processed information about
To provide visual evidence of their finding Smith s team filled neurons with calcium dye which provided an optical readout of spiking.
This revealed that dendrites fired spikes 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;
they seem to be a computational unit as well. is team plans to explore what this newly discovered dendritic role may play in brain circuitry and particularly in conditions like Timothy syndrome in
which the integration of dendritic signals may go awry. Several fellowships and grants helped fund the project including support from the Wellcome Trust the European Research Council and Gatsby Charitable Foundation.
Source: UNC-Chapel Hillyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license C
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