Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brain waves

10.11.2008
Electrical oscillations in one part of the brain suggest that it may interact with another to guide body movements

A seemingly simple action, such as picking up a pencil, actually involves complex communication between many parts of the central nervous system. Information about the pencil and its location enters the body through the eye, and eventually reaches a part of the brain called the somatosensory cortex.

There, this information seems to be encoded as two types of brain waves: gamma waves, which oscillate 30–80 times per second, and very fast oscillations (VFOs), which oscillate 80–160 times per second. These brain rhythms may then be conveyed to other parts of the brain to initiate and control the action of reaching out an arm to pick up the pencil.

If other parts of the brain also produce gamma waves and VFOs, it is possible that these brain regions could receive these signals from the somatosensory cortex, and communicate with this or other portions of the cerebral cortex to control movements. In fact, recent work measuring brain waves from the cerebellum, the part of the brain responsible for motor learning, indicates that the cerebellum may communicate with the cerebral cortex to regulate movement. A team of researchers, including Steven Middleton and Thomas Knöpfel from the RIKEN Brain Science Institute (BSI), Wako, Miles Whittington from Newcastle University, United Kingdom, and Roger Traub, now at IBM in New York, report these findings in the journal Neuron.

Tapping into brain waves

In slices from the mouse cerebellum that they had treated with nicotine, the researchers measured the frequency of oscillations using two methods: electrode recordings, and visualization of a voltage-sensitive dye. By both methods, they found that the cerebellar oscillations were a mixture of gamma waves and VFOs. These waves were almost identical in frequency to oscillations others had measured in the cerebral cortex during the same experimental conditions. This frequency match suggests that the cerebellum and cerebral cortex may exchange signals to control movement.

The cerebral cortex contains many types of neurons that are both excitatory and inhibitory. The excitatory neurons, which use glutamate as their chemical neurotransmitter, play an important role in regulating the oscillations of the cerebral cortical neuronal network. The cerebellum also contains some excitatory (granule) cells, while the rest consists of inhibitory neurons, which use GABA (γ-aminobutyric acid) as their neurotransmitter. The researchers demonstrated that the granule cells were not involved in generating the brain waves, so it was surprising that they observed these oscillations at all, since they had to have been generated by inhibitory neuronal populations only. The findings therefore indicate that brain areas with vastly different neuronal compositions can still produce similar rhythms.

Middleton, Knöpfel and colleagues also found another important difference between the cerebellum and the cerebral cortex. Oscillations in both brain regions can be triggered by activation of receptors for the neurotransmitter acetylcholine; however, the receptors in the cortex are so-called muscarinic receptors, which are not activated by nicotine, whereas the receptors in the cerebellum are triggered by nicotine. Furthermore, the cerebellar nicotine receptor that is acting to induce the brain waves seemed to be a ‘nonclassical’ nicotine receptor.

Unraveling neuronal communication

The network oscillations in the cerebral cortex occur due, in part, to gap junctions between cortical neurons, in which electrical activity in one cell can spread through channels that connect that neuron directly to its partner. The researchers also found many pieces of evidence that suggest that electrical connections also exist between cerebellar neurons.

First, they showed that a dye injected into a cerebellar output neuron, called the Purkinje cell, could diffuse to its neighboring local cerebellar interneuron, called a basket cell or a stellate cell. Then, they blocked all chemical communication that occurs in the spaces between neurons, called ‘synaptic neurotransmission’, by removing calcium ions from the solution bathing the cerebellar slices, and still observed VFOs. Finally, they blocked gap junctions with a drug, and this manipulation was sufficient to block both the gamma waves and the VFOs. Their results suggest that direct electrical connections between cerebellar neurons may be one mechanism by which network oscillations are regulated.

Visualizing the source of brain waves

Middleton, Knöpfel and colleagues then used electrical and optical recordings to pinpoint the area of the cerebellum which was responsible for generating the gamma waves and the VFOs. “Optical voltage imaging is a technique for which the RIKEN BSI Laboratory for Neuronal Circuit Dynamics attains world-wide recognition,” says Knöpfel. ”We are expecting that the use of optical voltage imaging in this research field will increase over the coming years.”

The researchers also confirmed their findings in slices from the human cerebellum, suggesting that the data could also be relevant to motor function in humans. Because the oscillations were stimulated by nicotine, the findings imply that nicotine from cigarette smoking may have effects on motion—such as tremor—owing to effects on network oscillations in the cerebellum.

This research provides insight into how the cerebellum and cerebral cortex may communicate with each other to create, organize, and control movements. The researchers believe that their work establishes a new approach to the understanding of how the cerebellum handles information, suggesting that, as in cerebral cortex, oscillations are used for temporal coding of information.

“Startup of this exciting new research was made possible through a generous one-year grant from the directors’ fund of former BSI director Shunichi Amari,” explains Knöpfel. “While we have established the mechanisms underlying cerebellar oscillation generation, we now aim to study the behavioral correlates of these rhythms,” say Middleton and Knöpfel.

1. Middleton, S.J., Racca, C., Cunningham, M.O., Traub, R.D., Monyer, H., Knöpfel, T., Schofield, I.S., Jenkins, A. & Whittington, M.A. High-frequency network oscillations in cerebellar cortex. Neuron 58, 763–774 (2008).

The corresponding authors for this highlight are based at the RIKEN Laboratory for Neuronal Circuit Dynamics

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/562/
http://www.researchsea.com

More articles from Life Sciences:

nachricht Designer cells: artificial enzyme can activate a gene switch
22.05.2018 | Universität Basel

nachricht Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Designer cells: artificial enzyme can activate a gene switch

22.05.2018 | Life Sciences

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>