Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How brain rhythms organize our visual perception

09.09.2019

A team of neuroscientists from Göttingen and Tehran shows how our brain combines visual features to achieve a unified percept

Imagine that you are watching a crowded hang-gliding competition, keeping track of a red and orange glider’s skillful movements. Our brain uses separate circuits to achieve such outstanding tracking ability, one specialized to process color information and the other specialized for processing directions of motion.


Similar to how a radio receiver identifies the radio transmitter from which a signal originates, high level areas of our brain distinguish the source of a neural input activity based on its frequency.

German Primate Center

This allows for optimal perceptual performance, but how do we perceptually combine the color and direction information into our unified percept of the glider, or any other object?

A German-Iranian team of scientists now discovered that the brain’s specialized color and motion circuits use different frequencies to broadcast their output to brain areas that combine the various visual feature components into a unified percept (PNAS 2019).

To investigate how information of different visual features is processed in the brain, the neuroscientists from the German Primate Center – Leibniz Institute of Primate Research in Göttingen, Germany, the Iran University of Science and Technology and the Institute for Research in Fundamental Sciences in Tehran, Iran measured the activity of individual nerve cells in the brain of rhesus monkeys, while the animals performed a visual perception task.

The monkeys were trained to report changes in moving patterns on a computer screen. Using hair-thin microelectrodes, which are painless for the animals, the researchers measured the electrical activity of groups of nerve cells. These signals continuously oscillate over a broad frequency spectrum.

The scientists recorded the activity in the brain area highly specialized for the processing of visual motion information. Using advanced signal processing techniques, they found that the activity of those nerve cells oscillates at high frequencies (around 200 cycles per second) and that these oscillations are linked to perception.

“We observed that faster responses of the animals occurred whenever the nerve cells showed a stronger oscillatory activity at high frequencies, suggesting that these oscillations influence perception and action,” explains Stefan Treue, head of the Cognitive Neuroscience Laboratory at the German Primate Center and one of the senior authors of the study.

Previous studies had shown that different visual aspects, such as the color and motion direction of visual objects, are analyzed in highly specialized, anatomically separate brain areas. These areas then transmit their information to high-level brain areas, where individual features are combined to form our unified percept of visual objects.

It turns out that the brain region processing color information transmits information via a lower frequency (around 70 cycles per second) than the high-frequency transmission of the brain region processing motion signals.

“Our computational analysis shows that high level regions could use these different frequencies to distinguish the source of neural activity representing the different features,” explains Mohammad Bagher Khamechian, scientist at the Iran University of Science and Technology in Tehran and first author of the study.

The detailed knowledge of how the brain of rhesus monkeys enables perception as well as other complex cognitive functions provides insights about the same processes in the human brain. “The oscillatory activity of neurons plays a critical role for visual perception in humans and other primates,” summarizes Stefan Treue.

“Understanding how exactly these activity patterns are controlled and combined, not only helps us to better understand the underlying neural correlates of conscious perception, but also may enable us to gain a better understanding of physiological deficits underlying disorders that involve perceptual errors, such as in schizophrenia and other neurological and neuropsychiatric diseases.”

Contact and suggestion for editors

Printable pictures and an animation are available in our media library. The press release is also available on our website. We kindly request a specimen copy in case of publication.

The German Primate Center (DPZ) – Leibniz Institute for Primate Research conducts biological and biomedical research on and with primates in the fields of infection research, neuroscience and primate biology. The DPZ maintains four field stations in the tropics and is the reference and service center for all aspects of primate research. The DPZ is one of 95 research and infrastructure facilities of the Leibniz Association.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Stefan Treue
Phone: +49 (0) 551 3851-118
Email: streue@dpz.eu

Dr. Moein Esghaei
Tel.: +49 (0) 551 3851-344
E-Mail: aesghaei@dpz.eu

Originalpublikation:

Khamechian MB, Kozyrev V, Treue S, Esghaei M, Daliri MR (2019): Routing information flow by separate neural synchrony frequencies allows for functionally labeled lines in higher primate cortex. PNAS, https://doi.org/10.1073/pnas.1819827116

Weitere Informationen:

https://www.dpz.eu/en/home/single-view/news/wie-hirnrhythmen-unsere-visuelle-wah... Press release
http://medien.dpz.eu/webgate/keyword.html?currentContainerId=4801 Printable Images
https://youtu.be/FYD_Z48MuDs Animation on YouTube

Dr. Susanne Diederich | idw - Informationsdienst Wissenschaft

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A molecular 'atlas' of animal development

Researchers from the University of Pennsylvania provide a molecular map of every cell in a developing animal embryo

In a paper in Science this week, Penn researchers report the first detailed molecular characterization of how every cell changes during animal embryonic...

Im Focus: Next generation video: WDR and Fraunhofer HHI present significantly improved video quality at IFA 2019

The demand for even higher resolution videos will continue to increase in the coming years. For this reason, the German public service broadcaster WDR and the Fraunhofer Heinrich Hertz Institute HHI will collaborate in the coming months to test the Video Coding possibilities offered by the next international standard VVC/H.266.

VVC/H.266 is the successor standard to HEVC/H.265. The latter is currently the most modern and efficient standard for Video Coding and is used, for example, in...

Im Focus: Nanodiamonds in the brain

The recording of images of the human brain and its therapy in neurodegenerative diseases is still a major challenge in current medical research. The so-called blood-brain barrier, a kind of filter system of the body between the blood system and the central nervous system, constrains the supply of drugs or contrast media that would allow therapy and image acquisition. Scientists at the Max Planck Institute for Polymer Research (MPI-P) have now produced tiny diamonds, so-called "nanodiamonds", which could serve as a platform for both the therapy and diagnosis of brain diseases.

The blood-brain barrier is a physiological boundary layer that works highly selectively and thus protects the brain: On the one hand, pathogens or toxins are...

Im Focus: Entanglement sent over 50 km of optical fiber

For the first time, a team led by Innsbruck physicist Ben Lanyon has sent a light particle entangled with matter over 50 km of optical fiber. This paves the way for the practical use of quantum networks and sets a milestone for a future quantum internet.

The quantum internet promises absolutely tap-proof communication and powerful distributed sensor networks for new science and technology. However, because...

Im Focus: Hamburg and Kiel researchers observe spontaneous occurrence of skyrmions in atomically thin cobalt films

Since their experimental discovery, magnetic skyrmions - tiny magnetic knots - have moved into the focus of research. Scientists from Hamburg and Kiel have now been able to show that individual magnetic skyrmions with a diameter of only a few nanometres can be stabilised in magnetic metal films even without an external magnetic field. They report on their discovery in the journal Nature Communications.

The existence of magnetic skyrmions as particle-like objects was predicted 30 years ago by theoretical physicists, but could only be proven experimentally in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

AI for Laser Technology Conference: optimizing the use of lasers with artificial intelligence

29.08.2019 | Event News

The power of thought – the key to success: CYBATHLON BCI Series 2019

16.08.2019 | Event News

 
Latest News

Fraunhofer FHR presents innovative contributions to radar applications in the automotive sector at the IAA

09.09.2019 | Trade Fair News

Warm on top, cold below: unexpected greenhouse gas effect in lakes

09.09.2019 | Life Sciences

Spintronics: Physicists discover new material for highly efficient data processing

09.09.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>