Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Understanding Fragile X syndrome with the blink of an eye

04.08.2005


While researchers have long known the genetic defect underlying Fragile X syndrome, they are still tracing how that defect creates the complex mix of mental retardation, hyperactive behavior, attention deficits, and other problems in the disorder. Fragile X is particularly important because it is the most common single-gene cause of mental retardation--affecting about 1 in 4000 males and 1 in 8000 females in the U.S.



In an article in the August 4, 2005, issue of Neuron, researchers led by Chris De Zeeuw of Erasmus University Rotterdam report that they have pinpointed a specific cause of defects in motor learning in Fragile X patients. Their work represents the first investigation of the role of abnormalities in the brain’s cerebellum in Fragile X syndrome.

Fragile X syndrome is caused by a defect in the Fragile X mental retardation 1 (Fmr1) gene, which in turns produces a nonfunctioning protein, FMRP. In their studies, De Zeeuw and colleagues studied the behavioral effects on motor learning and the effects on neurons in the cerebellum of knocking out this gene.


They found that mice lacking the gene showed deficits in a particular motor learning task known to be largely controlled by the cerebellum. In this "eyeblink conditioning" task, the mice were taught to associate a stimulus such as a tone with a puff of air on their eye, and the blink response was measured as an indication of how well the animals could learn the task. The researchers found that mice completely lacking the Fmr1 gene showed deficits in the motor learning task. But most importantly, the researchers also found that mice lacking the Fmr1 gene only in specific neurons, called Purkinje cells, in the cerebellum showed the deficit.

Detailed electrophysiological studies of Purkinje cells in such mutant mice revealed that the cells showed an enhanced weakening of their signaling connections--called long-term depression. The researchers also found that the Purkinje cells showed abnormalities in structures called dendrites, which are the branches from nerve cells that contain the receiving stations for signals from other neurons.

When the researchers conducted similar eyeblink conditioning tests in Fragile X patients, they found the same severe deficits.

And when the researchers created a mathematical model of long-term depression, they found that they could link alteration in signaling between neurons in the cerebellum with impairment in motor learning processes.

"Thus, while a lack of FMRP in areas such as the cerebral cortex, amygdala, and hippocampus may induce cognitive symptoms in Fragile X syndrome, the current data allow us to conclude that a lack of functional FMRP in cerebellar P cells may equally well lead to deficits in motor learning in Fragile X patients," concluded the researchers.

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

More articles from Life Sciences:

nachricht Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>