MedicineWorld.Org
Your gateway to the world of medicine
Home
News
Cancer News
About Us
Cancer
Health Professionals
Patients and public
Contact Us
Disclaimer

Medicineworld.org: How Lead Exposure Produces Learning Deficits

Back to pediatric news Blogs list Cancer blog  


Subscribe To Pediatric News RSS Feed  RSS content feed What is RSS feed?

How Lead Exposure Produces Learning Deficits

How Lead Exposure Produces Learning Deficits Tomas R. Guilarte, PhD
A study of young adult rats by scientists from the Johns Hopkins Bloomberg School of Public Health provides evidence that explains exactly how exposure to lead during brain development produces learning deficits. The study shows that exposure to levels of lead that are similar to those measured in lead-intoxicated children reduces the birth and survival of new neurons (neurogenesis) in the brain. Lead also alters the normal development of newly born neurons in a part of the brain (hippocampus) known to be important for learning and memory. The study is reported in the March 30, 2007, issue of Neuroscience.

"There was a dogma in neuroscience that you were born with all the neurons you would ever have, but that thinking has changed dramatically in the last 20 years," said Tomás R. Guilarte, PhD, senior author of the study and professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health. "The exciting idea is that researchers have discovered ways to increase the number of new neurons, and this may facilitate learning in the hippocampus portion of the brain".

The scientists studied young adult rats, using a group of lead-treated and non-treated (control) rats. When they examined the brains of lead-exposed rats, they observed that fewer neurons were born and those neurons that were born survived for a shorter amount of time and had abnormal development.

Guilarte explained that newly born neurons extend processes to form new connections with other neurons in the brain-like branches growing off of a tree limb-which allow learning and memory to take place. The length of the neuronal processes, called dendrites, in lead-exposed rats were shorter and twisted when in comparison to the long and relatively straight dendrites in neurons found in control rats.

"The fewer connections between neurons found in lead-exposed rats decrease their ability to communicate, which has a major impact on the rat's ability to learn. Previously, we knew that lead impaired cognitive function, but we didn't know exactly how," said Guilarte. "Now that we know that lead decreases neurogenesis in the hippocampus and alters the ability of these new neurons to communicate, in future studies we hope to determine if environmental enrichment can reverse these detrimental effects of lead".

Guilarte has studied lead's effects at the molecular level on rat brain development for more than a decade. In November 2002, Guilarte and his colleagues reported that environmental enrichment that stimulates brain activity can reverse the long-term learning deficits caused by lead poisoning.


Posted by: JoAnn    Source




Did you know?
A study of young adult rats by scientists from the Johns Hopkins Bloomberg School of Public Health provides evidence that explains exactly how exposure to lead during brain development produces learning deficits. The study shows that exposure to levels of lead that are similar to those measured in lead-intoxicated children reduces the birth and survival of new neurons (neurogenesis) in the brain. Lead also alters the normal development of newly born neurons in a part of the brain (hippocampus) known to be important for learning and memory. The study is reported in the March 30, 2007, issue of Neuroscience.

Medicineworld.org: How Lead Exposure Produces Learning Deficits

Asthma| Hypertension| Medicine Main| Diab french| Diabetes drug info| DruginfoFrench| Type2 diabetes| Create a dust free bedroom| Allergy statistics| Cancer terms| History of cancer| Imaging techniques| Cancer Main| Bladder cancer news| Cervix cancer news| Colon cancer news| Esophageal cancer news| Gastric cancer news| Health news| Lung cancer news| Breast cancer news| Ovarian cancer news| Cancer news|

Copyright statement
The contents of this web page are protected. Legal action may follow for reproduction of materials without permission.