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)... 20, 2016 Securus Technologies, a leading ... for public safety, investigation, corrections and monitoring announced ... it has secured the final acceptance by all ... Managed Access Systems (MAS) installed. Furthermore, Securus will ... be installed by October, 2016. MAS distinguishes between ...
(Date:6/9/2016)... , June 9, 2016 ... Police deploy Teleste,s video security solution to ensure the safety ... France during the major tournament Teleste, ... communications systems and services, announced today that its video security ... to back up public safety across the country. ...
(Date:6/2/2016)... --  The Weather Company , an IBM Business (NYSE: ... in which consumers will be able to interact with IBM ... voice or text and receive relevant information about the product ... have long sought an advertising solution that can create a ... and valuable; and can scale across millions of interactions and ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... Hill, N.C. (PRWEB) , ... June 27, 2016 ... ... U.S. commercial operations for Amgen, will join the faculty of the University ... serve as adjunct professor of strategy and entrepreneurship at UNC Kenan-Flagler, with a ...
(Date:6/24/2016)... Epic Sciences unveiled a liquid biopsy ... PARP inhibitors by targeting homologous recombination deficiency (HRD) ... test has already been incorporated into numerous clinical ... Over 230 clinical trials are investigating ... PARP, ATM, ATR, DNA-PK and WEE-1. Drugs targeting ...
(Date:6/23/2016)... ... June 23, 2016 , ... UAS LifeSciences, one of ... their brand, UP4™ Probiotics, into Target stores nationwide. The company, which has been ... Target to its list of well-respected retailers. This list includes such fine stores ...
(Date:6/23/2016)... Houston Methodist Willowbrook Hospital has signed ... to serve as their official health care provider. ... will provide sponsorship support, athletic training services, and ... volunteers, athletes and families. "We are ... and to bring Houston Methodist quality services and ...
Breaking Biology Technology: