Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Optogenetic probes to image brain electrical activity in laboratory mice

14.07.2010
RIKEN scientists have developed a genetically-encoded fluorescent sensor that can act as a direct optical indicator of signaling activity in the living brain.

This powerful tool, described in a new article from Nature Methods, promises to help neuroscientists identify and monitor the behavior of neural circuits involved in motor activity, sensory perception and other functions.

Researchers have historically analyzed the complex electrical activity of the brain using an invasive approach involving tiny electrodes, whose large size relative to individual nerve cells has limited the number of locations from which neuronal activity can be sampled. Optimal imaging methods overcome this limitation with molecular size probes that transform the electrical signals into an optical reporter signal.

The voltage-sensitive fluorescent proteins (VSFPs) developed by Thomas Knöpfel’s team at the RIKEN Brain Science Institute represent an important step in this direction. These are engineered proteins that reside within the membranes of neurons, each of which is fused to two different fluorescent proteins. Whenever a neuron receives a stimulatory signal, the resulting change in voltage potential in the cell membrane causes the VSFPs to rearrange into a configuration that causes a readily detectable change in the optical signal generated by the VSFP, in a phenomenon known as Förster Resonance Energy Transfer.

Knöpfel’s laboratory pionered the development of these sensors for more than 10 years but up to now the function of these probes was only demonstrated by recording electrical activity from 2-dimensional networks of cultured nerve cells. In the latest edition of Nature Methods, the team presents the first experimental confirmation that these probes are able to report electrical activity of nerve cells in the brains of living mice. The researchers used genetically modified mice to localize the VSFP probe within specific subsets of cortical neurons within a brain area called the somatosensory cortex. Each mouse whisker is wired to discrete neural circuits in the somatosensory cortex, and the researchers found that they could readily detect changes in the membrane voltage of these circuit elements as each whisker was manipulated. Based on these experiments, they were essentially able to reconstruct maps of the cell populations that operate as ‘receptive areas’ for individual whiskers.

Being genetically encoded, VSFPs offer several advantages over other commonly-used approaches to monitoring neuronal activity. They can essentially be ‘programmed’ for selective expression within specific subtypes of neurons or particular regions of the brain, and could be used to chart long-range neural circuits extending over considerable distances, unlike fluorescent dyes that label cells non-specifically and can only be applied within a relatively limited volume of the brain. Other genetically-encoded sensors have been developed that respond to calcium flux in the immediate aftermath of neuronal firing, but these represent indirect indicators and generally respond more slowly to neuronal activity.

Given the high degree of spatial and temporal resolution displayed by the VSFPs in this study, Knöpfel is confident that they will prove a useful tool for researchers hoping to understand how patterns of neuronal activity correlate with behavior or physiological changes in the living brain. “The ability of VSFPs to report faster signals, along with genetic targeting, will allow new approaches to the study of the dynamic interaction of assemblies of neurons,” he says. “This will facilitate the investigation of fundamental questions of information processing in the brain, such as the circuit operations involved in sensing our environment and generation of body movements, but will also be applicable to directly visualize cognitive functions.”

For more information, please contact:

Dr. Thomas Knöpfel
Laboratory for Neuronal Circuit Dynamics
RIKEN Brain Science Institute
Tel: +81-(0)48-467-9740 / Fax: +81-(0)48-467-9739
Ms. Tomoko Ikawa (PI officer)
Global Relations Office
RIKEN
Tel: +81-(0)48-462-1225 / Fax: +81-(0)48-462-4715
Email: koho@riken.jp

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht Ambush in a petri dish
24.11.2017 | Friedrich-Schiller-Universität Jena

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>