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 Immune Defense Without Collateral Damage
23.01.2017 | Universität Basel

nachricht The interactome of infected neural cells reveals new therapeutic targets for Zika
23.01.2017 | D'Or Institute for Research and Education

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | 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

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>