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
Flavins keep a handy helper in their pocket
25.04.2018 | University of Freiburg
Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
25.04.2018 | Physics and Astronomy
25.04.2018 | Physics and Astronomy
25.04.2018 | Information Technology