(Press-News.org) Some neurons are more active than others, even when they are positioned right next to each other and are one and the same neuron type. Dr. Jean-Sébastien Jouhanneau and Dr. James Poulet of the Max Delbrück Center for Molecular Medicine (MDC) Berlin Buch have discovered the cause for this phenomenon. They found that the more active neurons in the somatosensory area of the brain respond to a broader receptive field and probably play a particularly important role in our sensory perception. The findings of the researchers, who also work at the NeuroCure Cluster of Excellence at Charité in Berlin, have now been published in the journal Neuron*.
Billions of neurons process signals in our brain. In the sensory part of our cerebral cortex, which is responsible for perceptions of the outside world, not all neurons are equally active: even neurons positioned directly next to each other can be differentially active. If there is input of a stimulus, some neurons respond more than their neighbors. Until now, the reason for this remained elusive. Are the more active neurons perhaps more strongly connected within the cortex? Or do they get more information from upstream areas of the brain?
To clarify this, the researchers stimulated the whiskers of mice and investigated how different neurons in the brain react. For this purpose, they measured the activity of two neurons simultaneously. The active cells are characterized by a high concentration of the protein cFos. Since this was coupled to the green fluorescent protein (GFP), the researchers were able to distinguish more active cells from less active ones.
First they stimulated only one central whisker. Surprisingly, no differences showed up between the two neurons. However, if the researchers stimulated many whiskers at the same time with a short airpuff, the response of the GFP-labeled neuron was significantly earlier and larger. Apparently, the more active neurons are distinguished by the fact that they respond to a wider receptive field. But where does this information come from?
Before we perceive a stimulus from our environment, it must pass through the thalamus in the brain. This area is therefore also called "the gateway to consciousness". In mice, the signals from the whiskers are processed in two areas of the thalamus, the so-called ventral posteromedial nucleus (VPM) and the area of the posteromedial nucleus (POm). Using optogenetic stimulation, the team led by James Poulet determined which of these two nuclei is responsible for the enhanced response of specific neurons. By means of light impulses in the brain, they could specifically activate the thalamic nuclei and thus selectively simulate a flow of information through one of the two nuclei.
If the scientists activated the VPM, both types of neurons showed an equally strong response. They behaved exactly as if only a single whisker was touched. This specific reaction is thus apparently mediated by the VPM. The POm, by contrast, elicited - just like the stimulation of several whiskers - a stronger and faster response of the GFP-labeled neurons.
The POm is known for covering a broad receptive field and for transmitting the signals to widely distributed areas in the cerebrum. According to current research, the most active neurons in the somatosensory (touch-sensitive) cortex are characterized by the fact that they not only get specific information from the VPM, but can also draw on the wide receptive field of the POm. This parallel processing of specific and large-scale stimulus information by separate groups of neurons could be a fundamental mechanism of sensory perception. The more active neurons may have a particularly important role in sensory perception.
INFORMATION:
* Cortical fosGFP Expression Reveals Broad Receptive Field Excitatory Neurons Targeted by POm
Jean-Sébastien Jouhanneau1,2, Leiron Ferrarese1,2, Luc Estebanez1,2, Nick J. Audette3, Michael Brecht2,4, Alison L. Barth3, James F.A. Poulet1,2,*
1 Department of Neuroscience, Max Delbrück Center for Molecular Medicine (MDC), Berlin-Buch, Robert-Rössle-Str. 10, 13092 Berlin, Germany
2 Cluster of Excellence NeuroCure, Neuroscience Research Center, Charité -Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
3 Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213, USA
4 Bernstein Center for Computational Neuroscience (BCCN), Humboldt University Berlin, Philippstrasse 13, 10115 Berlin, Germany
Contact:
Barbara Bachtler
Press Department
Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch
in the Helmholtz Association
Robert-Rössle-Straße 10
13125 Berlin
Germany
Phone: +49 (0) 30 94 06 - 38 96
Fax: +49 (0) 30 94 06 - 38 33
e-mail: presse@mdc-berlin.de
https://www.mdc-berlin.de/en
People and animals have been shown to discriminate between quantities. Lions, chimpanzees and hyenas, for example, will only approach a group of attackers if their own group outnumbers that of the intruders. These animals use numerical information to make decisions about their social life.
Testing numerical competence
In 2012 Friederike Range and Zsofia Virányi from the Messerli Research Institute at the University of Veterinary Medicine Vienna showed that wolves are capable of discriminating between different food quantities. In their present study, they asked ...
Stimulants use such as cocaine and amphetamine is associated with a nearly two-fold greater likelihood of suicidal behaviour amongst people who inject drugs, say researchers at the University of Montreal and the CHUM Research Centre. Drug addiction had already been identified as a major risk factor for suicide, and it is in fact the cause of ten percent of deaths among drug users. The data from this groundbreaking study could help develop and evaluate more appropriate suicide prevention efforts in this highly vulnerable population.
The researchers were able to explore ...
GPs should consider a more overt discussion with patients when referring them for further investigation of symptoms which may indicate cancer, according to a paper published in the British Journal of General Practice.
In an NIHR-funded study, researchers from the Universities of Bristol, Cambridge, Durham and Exeter conducted interviews with patients being referred for possible lung and colorectal cancer.
They found that patients were rarely involved in the decision to be referred for investigation and that reasons for referral tended to be couched in non-specific ...
WASHINGTON, Dec. 16, 2014 -- It's been a holiday decoration staple for decades, and it turns out that silver stuff hanging from your tree has quite a storied past. Tinsel has been made out of everything from real silver, to lead to other dangerously flammable materials. This week's Speaking of Chemistry decks your halls with the history of tinsel. Check it out at http://youtu.be/fql3aCuu1l0.
INFORMATION:
Speaking of Chemistry is a production of Chemical & Engineering News, a weekly magazine of the American Chemical Society. The program features fascinating, weird and ...
University of Guelph researchers hope their new discovery will help combat a disease killing honeybee populations around the world.
The researchers have found a toxin released by the pathogen that causes American foulbrood disease -- Paenibacillus larvae (P. larvae) -- and developed a lead-based inhibitor against it.
The study was published in the December issue of the Journal of Biological Chemistry.
The finding provides much-needed insight into how the infection occurs, said Rod Merrill, a professor in Guelph's Department of Molecular and Cellular Biology and a ...
PROVIDENCE, R.I. [Brown University] -- Newly published research provides the first demonstration of how a genetic mutation associated with a common form of albinism leads to the lack of melanin pigments that characterizes the condition.
About 1 in 40,000 people worldwide have type 2 oculocutaneous albinism, which has symptoms of unsually light hair and skin coloration, vision problems, and reduced protection from sunlight-related skin or eye cancers. Scientists have known for about 20 years that the condition is linked to mutations in the gene that produces the OCA2 protein, ...
JACKSONVILLE, Fla. -- It may not be necessary for experienced gastroenterologists to send polyps they remove from a patient's colon to a pathologist for examination, according to a large study conducted by physician researchers at the Jacksonville campus of Mayo Clinic.
Their 522-patient study, published in the December issue of Gastrointestinal Endoscopy, found that physicians correctly evaluated whether a polyp was precancerous or benign using high-definition optical lenses during a colonoscopy. Their assessment was 96 or 97 percent accurate -- depending on which of ...
There are consequences of the successful efforts worldwide to save beavers from extinction. Along with the strong increase in their population over the past 100 years, these furry aquatic rodents have built many more ponds, establishing vital aquatic habitat. In doing so, however, they have created conditions for climate changing methane gas to be generated in this shallow standing water, and the gas is subsequently released into the atmosphere. In fact, 200 times more of this greenhouse gas is released from beaver ponds today than was the case around the year 1900, estimates ...
Use of cigarettes, alcohol, and abuse of prescription pain relievers among teens has declined since 2013 while marijuana use rates were stable, according to the 2014 Monitoring the Future (MTF) survey, released today by the National Institute on Drug Abuse (NIDA). However, use of e-cigarettes, measured in the report for the first time, is high.
These 2014 results are part of an overall two-decade trend among the nation's youth. The MTF survey measures drug use and attitudes among eighth, 10th, and 12th graders, is funded by NIDA, and is conducted by researchers at the ...
EAST LANSING, Mich. --- Domestic violence can affect children even before they're born, indicates new research by Michigan State University scientists.
The study is the first to link abuse of pregnant women with emotional and behavioral trauma symptoms in their children within the first year of life. Symptoms include nightmares, startling easily, being bothered by loud noises and bright lights, avoiding physical contact and having trouble experiencing enjoyment.
"For clinicians and mothers, knowing that the prenatal experience of their domestic violence can directly ...
