The Thalamus not only relays visual signals from the eye to the visual cortex as previously thought, but also conveys additional, contextual information. Integrating these different signals is essential to understand and interpret what we see in the world around us. Prof. Sonja Hofer and her research team at the Biozentrum, University Basel, investigate how the brain processes visual stimuli and how contextual information shapes our visual perception. Their latest findings are reported in “Nature Neuroscience”.
As soon as we open our eyes in the morning, our brain is flooded with images. Information about these images is sent from the eyes to a brain region called the thalamus, and from there on to the visual cortex. The visual cortex, which comprises the largest part of the human brain, is responsible for analyzing visual information and allows us to see.
In contrast, the thalamus has until now been considered mostly as a relay for visual information. The research team led by Prof. Sonja Hofer at the Biozentrum, University of Basel, has discovered in mice that a special part of the thalamus — called the Pulvinar — supplies the visual cortex with additional, non-visual information.
Contextual information is essential for visual perception
What we see is not only based on the signals that our eyes send to our brain, but is influenced strongly by the context the visual stimulus is presented in, on our previous knowledge, and expectations. Optical illusions, as the one shown here, illustrate how important such non-visual, contextual information is for our perception.
The visual cortex receives this additional information from other brain areas and uses it to allow us to understand and interpret the visual world. Prof. Hofer and her team measured the specific signals transmitted to visual cortex from the Thalamus, and found that the Pulvinar not only conveyed visual signals but is also one of the brain areas that provide additional information about the context of visual stimuli.
Movements in the environment can be detected effectively
Moreover, the researchers could identify this additional information in more detail. For example, the Pulvinar sends signals about sudden, unpredicted motion in the environment which is not caused by the animal’s own movements.
“Visual signals that the brain cannot predict might be especially important, such as a car that suddenly appears, or maybe an approaching predator in the case of the mouse. The Pulvinar might facilitate the detection of these stimuli,” explains Dr Morgane Roth, one of the authors of the study.
Although the Pulvinar is the largest part of the thalamus in humans, its function is still largely unknown. The researchers’ findings begin to shed some light on the role of this mysterious structure.
Another piece of the puzzle are the signals sent back to the Pulvinar from visual cortex, which seem to make information flow back and forth between the two parts of the brain in a loop. Why this is the case is still completely unclear. Prof. Hofer’s team is now planning to study these visual loops, and to find out how signals from the Pulvinar influence our visual perceptions and actions.
Morgane M. Roth, Johannes C. Dahmen, Dylan R. Muir, Fabia Imhof, Francisco J. Martini, Sonja B. Hofer
Thalamic nuclei convey diverse contextual information to layer 1 of visual cortex.
Nature Neuroscience (2015) | doi:10.1038/nn.4197
Heike Sacher, University of Basel, Biozentrum, phone: +41 61 267 14 49, email: firstname.lastname@example.org
Heike Sacher | Universität Basel
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences