Navigation Links
Abnormal brain circuits may prevent movement disorder
Date:8/5/2009

MANHASSET, NY -- Most people who carry a genetic mutation for a movement disorder called dystonia will never develop symptoms, a phenomenon that has puzzled scientists since the first genetic mutation was identified in the 1990's. Now, scientists at The Feinstein Institute for Medical Research have figured out why these mutation carriers are protected from symptoms of the disorder they have an additional lesion that evens the score.

Dystonia is marked by uncontrolled movements, particularly twisting and abnormal postures. Studies have shown that muscles contract abnormally and patients can't stop the involuntary movements. The identification of a specific abnormality in people with the genetic mutation who never develop symptoms could eventually pave the way towards new treatments for dystonia patients. There are half a million people in the United States alone. The brains of people with inherited dystonia are normal at autopsy and the exact cause of their movement abnormality is unknown.

David Eidelberg, MD, the senior author of the study published in the Journal of Neuroscience, said that they used diffusion tensor imaging a type of magnetic resonance imaging (MRI) that measures changes in the integrity of white matter pathways in the brain to study those with and without symptoms who carry the disease gene. There were 20 people in the study; 12 with symptoms and eight without. They also had a number of volunteers who agreed to brain scans who had no disease and no mutations in the gene for dystonia.

Dr. Eidelberg and his colleagues identified two discrete areas along the pathway that links the cerebellum to the motor cortex that together determine whether a mutation carrier will display clinical manifestations of the disease.

Their earlier work revealed that patients and non-patients with the disease gene have the same underlying functional brain abnormality, such as overactivity of motor circuits that make it hard to process sequential information. Nonetheless, mutation carriers have a characteristic circuit disorder involving a motor system that is revved up and idling at high speed, making it difficult to integrate the information needed to plan movements and to learn new motor skills. It was not suspected that these otherwise healthy individuals had such difficulties since doctors only saw those who presented with the uncontrollable movements.

While their brains show the same abnormal network, only approximately 30% of people who carry the mutated gene called DYT1 will develop the involuntary movements that can prevent them from living a normal life, according to Dr. Eidelberg.

The puzzle was why.

In the latest study, the new advances in diffusion imaging allowed them to see something for the first time. They saw that there were two places along the motor pathway that seemed to stop the flow of neural signals from one part of the circuit to the other. Those with only one lesion in the circuit developed the debilitating movements and those with two lesions did not. "There is something about this second lesion that is protective," the authors concluded. "We found a consistent cerebellar pathway problem in all DYT1 carriers. When we went back and looked at those without symptoms, we saw that they had an additional lesion downstream in the portion of the pathway connecting directly to the motor cortex." This second area of pathway disruption abrogated the effects of the first lesion.

Normally, the cerebellum (a region that controls movement) puts the breaks on the motor cortex by potentiating inhibition at the cortical level. It is likely that mutation carriers have a developmental problem in the flow of neural signals along this circuit such that the brain can't inhibit an unwanted movement. With the second pathway lesion, Dr. Eidelberg explained, "the flow is shut off and the abnormal activity stops."


'/>"/>

Contact: Jamie Talan
jtalan@nshs.edu
516-562-1232
North Shore-Long Island Jewish (LIJ) Health System
Source:Eurekalert

Related biology news :

1. New test can detect both genetic and chromosomal abnormalities in embryos
2. High carbon dioxide levels cause abnormally large fish ear bones
3. Prenatal meth exposure linked to abnormal brain development
4. Genetic abnormality may increase risk of blood disorders
5. Researchers examine developing hearts in chickens to find solutions for human heart abnormalities
6. Alcohol consumption can cause too much cell death, fetal abnormalities
7. Researchers study facial structures, brain abnormalities to reveal formula for detection of autism
8. Largest study of its kind implicates gene abnormalities in bipolar disorder
9. Obese men have less semen, more sperm abnormalities, and should lose weight before trying for a baby
10. New study points to agriculture in frog sexual abnormalities
11. Study examines genetic defects linked to body abnormalities in patients with childhood cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/20/2016)... DALLAS , June 20, 2016 ... criminal justice technology solutions for public safety, investigation, ... by the prisons involved, it has secured the ... Corrections (DOC) facilities for Managed Access Systems (MAS) ... (4) additional facilities to be installed by October, ...
(Date:6/7/2016)... , June 7, 2016  Syngrafii Inc. ... a business relationship that includes integrating Syngrafii,s patented ... branch project. This collaboration will result in greater ... the credit union, while maintaining existing document workflow ... http://photos.prnewswire.com/prnh/20160606/375871LOGO ...
(Date:6/1/2016)... Favorable Government Initiatives Coupled With ... Identification to Boost Global Biometrics System Market Through 2021  ... report, " Global Biometrics Market By Type, By ... 2011 - 2021", the global biometrics market is projected ... of growing security concerns across various end use sectors ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... ... launch of the Supplyframe Design Lab . Located in Pasadena, Calif., the ... future of how hardware projects are designed, built and brought to market. , ...
(Date:6/23/2016)... Calif. , June 23, 2016  Blueprint Bio, ... biological discoveries to the medical community, has closed its ... Matthew Nunez . "We have received ... with the capital we need to meet our current ... essentially provide us the runway to complete validation on ...
(Date:6/23/2016)... Pleasant Prairie, WI (PRWEB) , ... June 23, ... ... sciences consultancy focused on quality, regulatory and technical consulting, provides a free ... webinar is presented on July 13, 2016 at 12pm CT at no charge. ...
(Date:6/22/2016)... , June 22, 2016 Cell ... will allow them to produce up to one ... one lot within one week. These high-quality, consistent ... laboriously preparing cells and spend more time doing ... through a proprietary, high-volume manufacturing process that produces ...
Breaking Biology Technology: