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 Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

nachricht First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>