Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neurons work like a chain of dominos to control action sequences

25.10.2010
MIT neuroscientists identify chain reactions within the brain

As anyone who as ever picked up a guitar or a tennis racket knows, precise timing is often an essential part of performing complex tasks. Now, by studying the brain circuits that control bird song, MIT researchers have identified a "chain reaction" of brain activity that appears to control the timing of song.

The song of the zebra finch is very stereotypic; each song lasts about 1 second, and consists of multiple syllables whose timing is almost precisely the same from one performance to the next. "It's a great model system for studying how the brain controls actions", says Michale Fee, senior author of the study and a member of the McGovern Institute for Brain Research.

The brain structures involved in bird song production have been identified, and Fee and colleagues had previously shown that the tempo of the song is controlled by a brain area known as HVC. During the 1-second song, individual neurons in HVC fire just one short burst of activity at a precise time point within the song. Different neurons fire at different times, so the activity of these neurons represents a 'time stamp' that causes the correct instructions to be sent to the vocal organs at each instant within the song.

But how does each HVC neuron know when to fire with such perfect timing? Several different ideas have been proposed, but one especially appealing idea is the "synfire chain" model, in which neurons fire in a chain reaction – each one triggering the next in the sequence, like a cascade of falling dominos.

In a new study, which appears in the October 24 online issue of Nature, Fee and colleagues have now tested this idea using intracellular recordings, an approach that can record tiny voltage fluctuations in individual HVC neurons. In a technical tour-de-force, they developed a method in which these recordings could be made while the bird was freely moving around his cage and engage in natural behaviors such as singing.

Their results support the chain of dominoes model. When individual HVC neurons fire, they do so suddenly, as if hit by the preceding domino. There was no prior build-up of activity; instead, each neuron remained silent until its turn came to fire, at which point it showed a sudden burst of activity, presumably caused by excitatory input from the previous neuron in the chain. In further experiments, the authors showed that this burst of activity is triggered suddenly by an all-or-none influx of calcium through specialized membrane channels that open in response to this excitatory input.

The MIT researchers also showed that the timing of neural bursts in HVC neurons is not easily disturbed by small electrical perturbations. That's important, explains first author Michael Long, who is now at New York University's Langone Medical Center. "If one neuron made a mistake in its timing, every subsequent neuron down the chain would also be off. It would be like a musician with no sense of rhythm."

"This is the first time we've been able to understand the generation of a learned behavioral sequence", says Fee. "We predict that similar mechanisms probably exist in other brains, including our own."

Dezhe Jin of Pennsylvania State University also contributed to the study.

Source: "Support for a synaptic chain model of neuronal sequence generation," Long MA, Jin DZ, Fee MS. Nature. 24 Oct 2010.

Jen Hirsch | EurekAlert!
Further information:
http://www.mit.edu

Further reports about: HVC Nature Immunology brain structure chain reaction neurons

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>