Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How we keep track of what matters

23.02.2016

The visual system keeps track of relevant objects even as eye movements are made, shows a study by the German Primate Center

When watching basketball, we are easily able to keep track of the ball while also making frequent eye and head movements to look at the different players. Neuroscientists Tao Yao, Stefan Treue and B. Suresh Krishna from the German Primate Center (DPZ) in Göttingen, Germany, wanted to understand the neural mechanisms that allow us to see a stable world and keep track of relevant objects even without directly looking at them and when we shift our gaze.


When watching basketball, we are easily able to keep track of the ball while also making frequent eye and head movements to look at the different players. Image: Monkey Business Images/ Fotolia

Their study shows that the rhesus macaque’s brain “marks” relevant visual objects and rapidly updates the position of these markers as the monkey looks around. Since humans and monkeys exhibit very similar eye-movements and visual function, these findings are likely to generalize to the human brain. These results are also likely to be important for our understanding of disorders like schizophrenia, visual neglect and other attention deficit disorders (PLOS Biology).

The light that enters the eye falls onto the retina, where it is converted into neural activity that is then used by the brain to provide our sense of vision. The central part of the retina, the fovea, is specialized for more sensitive, higher-definition vision. It is therefore advantageous when viewing a scene, to move the eye so that it is centered successively (or fixated) on each important part of the scene, and light from these parts can fall onto the fovea and be analyzed in greater detail.

Indeed, both humans and monkeys make two to three fast eye movements every second in this manner, with each eye-movement lasting less than one-tenth of a second. Because the eye acts like a camera, each eye-movement results in a different view of the scene falling onto the retina.

However, despite these fast changes in viewpoint (which can also result from head movements), humans and monkeys do not see a scene that jumps around: Instead, they are able to “stitch together” the information obtained during each fixation to perceive a stable visual scene. They are also able to keep track of where relevant objects are in the scene even with these frequent changes in viewpoint. This is a very challenging task. Visual neurons respond more to relevant objects than to irrelevant ones. This increased response to relevant stimuli “marks” relevant stimuli.

Since each visual neuron in the brain only responds when a specific part of the retina is stimulated, each change in viewpoint with an eye-movement results in a different group of neurons being activated by a given visual stimulus before and after the eye-movement. This means that the “marking”, i.e. the information about which objects are relevant, needs to be transferred between different groups of neurons, so that after the eye-movement, these relevant objects continue to evoke larger responses and the brain can keep track of them. However, very little was known about the properties of such an information transfer in the brain, or even about whether it occurred at all.

In order to address this, neuroscientists Tao Yao, Stefan Treue and Suresh Krishna of the German Primate Center (DPZ) examined the responses of many single neurons in the brain of two monkeys while they attended to a stimulus without directly looking at it and made an eye-movement while maintaining attention on this stimulus.

To measure the activity of single neurons, the scientists inserted electrodes thinner than a human hair into the monkey’s brain and recorded the neurons’ electrical activity. Because the brain is not pain-sensitive, this insertion of electrodes is painless for the animal. By recording from single neurons in an area of the monkey’s brain known as area MT, the scientists were able to show that a transfer of information about the locations of relevant objects indeed occurs. However, no information is transferred about what the relevant objects look like.

“Our study shows how the primate brain is able to keep track of attended objects while ignoring irrelevant ones”, says Tao Yao, first author of the publication. It supports the idea that the brain maintains markers to attended stimuli and updates the locations of these markers with each eye-movement.

“Our results answer several important questions about how our brains see a stable visual world despite frequent intervening eye-movements. Also, because the updating of attentional markers is known to be impaired in schizophrenia, visual neglect and other attention deficit disorders, our results may help improve our understanding of these diseases”, Tao Yao comments on the findings.

Original publication
Tao Yao, Stefan Treue and B. Suresh Krishna: An attention-sensitive memory trace in macaque MT following saccadic eye movements. PLOS Biology.

Contact
Dr. Dr. med. Suresh Krishna
Tel: +49 551 3851-354
E-mail: skrishna@dpz.eu

Dr. Susanne Diederich (Communication)
Tel: +49 551 3851-359
E-mail: sdiederich@dpz.eu

Printable Images
Printable images are provided by the DPZ’s public relations department or may be downloaded from the photo database of our website. In case of publication, please send a copy or a link as reference.

The German Primate Center (DPZ) in Göttingen, Germany, conducts basic research on and with primates in the areas of infectious diseases, neurosciences and organismic biology. In addition, it operates four field stations abroad and is a competence and reference center for primate research. The DPZ is one of the 88 research and infrastructure institutions of the Leibniz Association in Germany. www.dpz.eu

Weitere Informationen:

http://medien.dpz.eu/webgate/keyword.html?currentContainerId=3142

Dr. Susanne Diederich | idw - Informationsdienst Wissenschaft

Further reports about: Leibniz-Institut disorders markers monkeys neurons stimulus

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>