Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Disarray in the brain


Neuroscientists from Lübeck investigate spontaneous neural activity

Our brain never rests completely: Even in situations without noticeable external input thousands of neurons are firing in different parts of the brain, a phenomenon neuroscientists refer to as “spontaneous activity” or even neural noise.

Fig. 1

Waschke et al.

Fig. 2

Waschke et al.

Scientists from the University of Lübeck now have discovered that the structure of this seemingly random noise in fact conveys double meaning: On the one hand spontaneous activity becomes more random with increasing age. On the other hand the current degree of irregularity affects the perception of our auditory environment.

Our brain changes as we get older: Connections between brain areas are rebuild, white matter is getting reduced, and local connections strengthened. These processes of reconstruction also affect spontaneous activity: “Neural noise becomes more random with increasing age”, explains Leonhard Waschke who conducted the study. “In this case it is not of importance if the brain is seemingly at rest or if it is busy solving a challenging cognitive task. The growing irregularity of neural noise thus seems to be a very stable feature of aging brains.”

At the same time, neural noise is in no way constant across time. The structure of spontaneous activity varies from second to second. Hence, moments of relative regularity at times are followed by moments of relatively large irregularity.

To investigate how the current degree of irregularity affects human perceptions and decisions, the scientists around Prof. Dr. Jonas Obleser chose an approach that may seem a little odd at first glance. While they recorded the brain activity of volunteers with the help of the electroencephalogram (EEG), these volunteers compared short tones regarding their pitch.

One thing however, was special about those tones: They were identical. Prof. Obleser explains: “Although human perception is very precise. It is not comparable to a machine which for the same input will always produce the very same output. Our perception is a highly subjective process that is affected by a number of cognitive and neuronal mechanisms, and hence also by the structure of neural noise.”

As a matter of fact, all volunteers perceived pronounced differences between the two identical tones and chose one of both as higher in pitch at the end of each trial. This decision was substantially influenced by the structure of spontaneous activity. The more irregular neural noise was during times of tone presentation, the more likely volunteers were to perceive the respective tone as higher in pitch.

The neuroscientists from the “Auditory Cognition” group describe the underlying mechanism like this: “If the auditory cortex is in a state of high irregularity, a new stimulus is processed more thoroughly and results in a clearer representation in the brain.” This seems to be enough to shift the perception in favor of the respective tone.

In a current study the scientists from Lübeck investigate this process in more detail by selectively presenting auditory material when the auditory cortex either is in an especially regular or irregular state.

Weitere Informationen:

Rüdiger Labahn | idw - Informationsdienst Wissenschaft

More articles from Studies and Analyses:

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Amputees can learn to control a robotic arm with their minds
28.11.2017 | University of Chicago Medical Center

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>



Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

More VideoLinks >>>