Brain Development

Gene Variants in Autism Linked to Brain Development

Source: 
Journal of Molecular Psychiatry, Gai et al.
Date Published: 
March 2011
Year Published: 
2011

This research on the genomics of autism confirms that the genetic roots of the disorder are highly complicated, but that common biological themes underlie this complexity. In the current study, researchers have implicated several new candidate genes and genomic variants as contributors to autism, and conclude that many more remain to be discovered. While the gene alterations are individually very rare, they mostly appear to disrupt genes that play important functional roles in brain development and nerve signaling. While an association between genomic variants in certain nervous system processes and autism has been hypothesized in the past, this research definitively links these biological functions to autism. 

"This large study is the first to demonstrate a statistically significant connection between genomic variants in autism and both synaptic function and neurotransmission," said senior author Peter S. White, Ph.D., a molecular geneticist and director of the Center for Biomedical Informatics at The Children's Hospital of Philadelphia. Synapses are the contact points at which nerve cells communicate with other nerve cells, while neurotransmitters are the chemical messengers carrying those signals.

"Prior genomic studies of autism have successfully identified several genes that appear to confer risk for autism, but each gene appears to contribute to only a small percentage of cases," said the lead author, Xiaowu Gai, Ph.D. "Our approach considered whether groups of genes with common biological functions collectively accounted for a greater percentage of autism risk."

-- via Science Daily http://www.sciencedaily.com/releases/2011/03/110301111243.htm.

Surprising View of Brain Formation: Discovery of a New Mechanism May Have Implications for a Host of Diseases

Source: 
Science Daily
Date Published: 
February 10, 2011
Abstract: 

A study from The Scripps Research Institute has unveiled a surprising mechanism that controls brain formation. In the new study, Mueller and colleagues focused on a protein called reelin. They found reelin is a key player in the migration of new nerve cells to the neocortex, the part of the brain responsible for higher-order functions, such as language and movement. The findings have implications for understanding a host of diseases, including some forms of mental retardation, epilepsy, schizophrenia, and autism.

Understanding the Autistic Mind

Source: 
Medical News Today
Date Published: 
February 1, 2011
Abstract: 

A study from MIT neuroscientists reveals that high-functioning autistic adults appear to have trouble using theory of mind to make moral judgments in certain situations. Specifically, the researchers found that autistic adults were more likely than non-autistic subjects to blame someone for accidentally causing harm to another person. This shows that their judgments rely more on the outcome of the incident than on an understanding of the person's intentions, says Liane Young, an MIT postdoctoral associate and one of the lead authors of the study.

Neural Stem Cells Retain High Levels on Reactive Oxygen Species, Study Finds

Source: 
Science Daily
Date Published: 
January 6, 2011
Abstract: 

Researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research have shown for the first time that neural stem cells, the cells that give rise to neurons, maintain high levels of ROS to help regulate normal self-renewal and differentiation. These findings may have significant implications for brain repair and abnormal brain development.

Prevalence of Autism According to Maternal Immigrant Status and Ethnic Origin

Source: 
Acta Psychiatrica Scandanavia, M.-J Dealberto
Date Published: 
January 2011
Year Published: 
2011

This study examined the rates of autism according to maternal immigrant status and ethnic origins based on the vitamin D insufficiency hypothesis, which proposes that maternal vitamin D insufficiency during pregnancy could be associated with autism. The study provided further support to the association between maternal immigrant status and an increased risk of autism. In addition, although more complex, ethnic origin was shown to have an effect on the rates of autism; the study found that black ethnicity demonstrated a higher incidence of autism, particularly when considering autism associated with mental retardation. The results found in the study are consistent with the maternal vitamin D insufficiency hypothesis. To understand the effect of maternal vitamin D insufficiency during pregnancy on the development of the fetal brain, neurobiological studies are necessary.

How Cortical Nerve Cells Form Synapses With Neighbors

Source: 
Science Daily
Date Published: 
December 22, 2010
Abstract: 

Newly published research led by Professor Z. Josh Huang, Ph.D., of Cold Spring Harbor Laboratory (CSHL) sheds important new light on how neurons in the developing brain make connections with one another. This activity, called synapse validation, is at the heart of the process by which neural circuits self-assemble, and is directly implicated in pathology that gives rise to devastating neurodevelopmental disorders including autism and schizophrenia.

A Set Of Brain Proteins Is Found To Play A Role In Over 100 Brain Diseases And Provides A New Insight Into Evolution Of Behavior

Source: 
Medical News Today
Date Published: 
December 21, 2010
Abstract: 

In research just published, scientists have studied human brain samples to isolate a set of proteins that accounts for over 130 brain diseases. The paper also shows an intriguing link between diseases and the evolution of the human brain.

Researchers Develop Mouse Model To Help Find How A Gene Mutation Leads To Autism

Source: 
Medical News Today
Date Published: 
December 20, 2010
Abstract: 

Researchers from Mount Sinai School of Medicine have found that when one copy of the SHANK3 gene in mice is missing, nerve cells do not effectively communicate and do not show cellular properties associated with normal learning. This discovery may explain how mutations affecting SHANK3 may lead to autism spectrum disorders (ASDs). The research is currently published in Molecular Autism.

Altered Functional Connectivity in Frontal Lobe Circuits Is Associated with Variation in the Autism Risk Gene CNTNAP2

Source: 
Pediatrics, Scott-Van Zeeland et al
Date Published: 
December 2010
Year Published: 
2010

People with a common variant of the CNTNAP2 gene, a gene associated with a heightened risk of autism, ADD/ADHD and other language difficulties, have a "disconnect" between their frontal lobe and other areas of the brain important for language, according to this fMRI study. The disconnect may help explain some of the language and communication difficulties that are characteristic of autism. About one-third of all people carry the variant of the CNTNAP2 gene.

Regardless of whether the test subjects had autism or not, children with the CNTNAP2 "risk" gene showed more activity in the frontal lobe of the brain during a "language learning" task than those without the 'risk' gene.

Changes in Prefrontal Axons May Disrupt the Network in Autism

Source: 
Journal of Neuroscience, Zikopoulos and Barbas
Date Published: 
December 2010
Year Published: 
2010

A post-mortem investigation measuring features of the different axons traveling beneath the cortical surface. The crux of the study is whether in autism there are changes in axons, "which are the conduit for neural communication." In comparison to control samples, autism brain tissue had fewer large axons connecting regions of the prefrontal cortex to the other areas of cortex.  Added to this connection imbalance is a thinner coat of axon insulation, called myelin. These findings may help explain why individuals with autism do not adequately shift attention, engage in repetitive behavior, and avoid social interactions.