Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A genetic disorder yields insight into genes and cognition

02.09.2004


Researchers attempting to understand the stunningly complex machinery by which genes give rise to the brain often find invaluable clues in genetic disorders that affect brain structure and function.



Andreas Meyer-Lindenberg and his colleagues have gained just such clues by studying the brain function of sufferers of Williams syndrome (WS). This rare disorder, caused by the deletion of a specific chromosome segment, can cause mental retardation, physical abnormalities, and personality disorder. But most intriguing to Meyer-Lindenberg and his colleagues is that the disorder causes a specific inability to visualize an object as a set of parts--for example, to assemble a simple piece of furniture.

In brain-imaging studies of people with WS, the researchers sought to shed light on the neurological malfunction that underlies this inability. In particular, they sought to determine whether the functional disorder could reveal the "modularity" of the processing of visual information in the brain’s visual cortex.


The visual cortex is basically organized into two processing pathways--a ventral pathway that processes the identity of objects and a dorsal pathway that processes spatial information on them. Thus, reasoned the researchers, the weakness in "visuospatial construction" in people with WS likely lies in the dorsal pathway.

In their experiments, the researchers performed functional magnetic resonance imaging (fMRI) of the brains of 13 volunteers with WS, as they asked the volunteers to perform two perceptual tasks. Such fMRI imaging involves using harmless magnetic fields and radio waves to image blood flow in the brain, which reveals brain activity.

In one set of experiments, the researchers asked the subjects to determine whether sets of geometric shapes could be assembled into a square. In another, they asked the patients to concentrate on either the identity of images of faces or houses, or their location. In normal people, attention to identity would activate the ventral stream, and attention to location would activate the dorsal stream.

The fMRI images revealed that the people with WS showed significantly lower neural activity in the dorsal stream of the visual cortex.

Higher-resolution structural MRI imaging revealed a reduction in the volume of gray matter in an adjacent brain region. The researchers’ studies also showed that impaired input from this region could cause the reduced function.

The researchers concluded that "Our observations confirm a longstanding hypothesis about dorsal stream dysfunction in WS, demonstrate effects of a localized abnormality on visual information processing in humans, and define a systems-level phenotype for mapping genetic determinants of visuoconstructive function."

Such insights, they said, should help scientists trace the genetic origin and molecular causes of the disorder.

Heidi Hardman | EurekAlert!
Further information:
http://www.cell.com

More articles from Life Sciences:

nachricht Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>