Additional brief reports
Genes for autism and schizophrenia only active in developing brains
February 11, 2013
Genes linked to autism and schizophrenia are only switched on during the early stages of brain development, according to a study in mice.
It has been suspected for a long time that if the development of the cortex is disrupted by genetic abnormalities or environmental stress (such as prematurity) this would have long-lasting adverse effects on brain development and could lead to problems like ADHD or autism. This study defines genes that are important in mice at this critical period and this does indeed seem to include genes known to predispose to autism and schizophrenia.
http://medicalxpress.com/news/2013-02-genes-autism-schizophrenia-brains.html
Scientists investigate inherited causes of autism
February 4, 2013
Two new studies investigate the role recessive genes play in ASD. These genes can be passed on through generations, but their effects are seen only if an individual inherits two identical copies of the gene – one from each parent.
One study found that approximately 5% of autism cases could be linked to inherited, recessive mutations that completely disrupt gene function. A second study found that autism risk could also be attributed to inherited mutations that resulted in only a partial loss of gene function.
The number of different genetic mutations uncovered by the two studies supports the long-held theory that autism is a heterogeneous condition with many different genetic causes.
http://medicalxpress.com/news/2013-02-scientists-inherited-autism.html
Gene target shows promise for autism
January 3, 2013
Mouse study found that chemically normalizing excessive levels of protein synthesis induced by a variant of the EIF4E gene, whose mutation is associated with autism, significantly reduced autistic-like behaviors. The mice were less likely to engage in repetitive behaviors, more likely to interact with other mice, and were successful in navigating mazes that differed from those they previously solved.
http://www.futurity.org/health-medicine/gene-target-shows-promise-for-autism/
Air pollution drives up autism risk
Exposure to traffic-related air pollution during pregnancy and the first year of life was associated with a more than two-fold risk of autism. Exposure to regional pollution was also associated with autism even if the mother did not live near a busy road.
http://www.futurity.org/health-medicine/air-pollution-drives-up-autism-risk/
note criticism of the study: http://www.forbes.com/sites/emilywillingham/2012/11/27/5-caveats-about-the-autism-and-air-pollution-study/
Autism risk test is 70% accurate
September 12, 2012
A new genetic test predicted a person’s risk of developing an autism spectrum disorder with over 70% accuracy. Participants were all of central European descent. The test uses 237 genetic markers (SNPs) in 146 genes and related cellular pathways.
http://www.futurity.org/health-medicine/autism-risk-test-is-70-percent-accurate/
Unreliable neural response in autistic adults
September 20, 2012
A small study shows that autistic adults have unreliable neural sensory responses to visual, auditory, and somatosensory, or touch, stimuli. This poor response reliability appears to be a fundamental neural characteristic of autism. Non-autistic individuals showed reliably consistent brain activity to sensory information, while autistic individuals showed marked trial-by-trial variability. It’s suggested that such unreliable activity might be what’s limiting the development of social and language abilities.
http://www.futurity.org/health-medicine/unreliable-neural-response-in-autistic-adults/
Electrical Activity in the Brain Can Distinguish Children With Autism
June 27, 2012
A large study found that patterns of electrical activity in the brain can distinguish children with autism from children with typical brains as early as age 2. In general, autistic children showed reduced connectivity.
http://blogs.edweek.org/edweek/speced/2012/06/electrical_activity_in_the_brain_can.html
Autism and schizophrenia may share root cause
July 3, 2012
The risk of an autism spectrum disorder may be higher among people whose parents or siblings have been diagnosed with schizophrenia or bipolar disorder.
The presence of schizophrenia in parents was associated with an almost three times increased risk for autism spectrum disorders in Swedish groups. Schizophrenia in a sibling also was associated with roughly two and a half times the risk for autism in the Swedish national group and a 12 times greater risk in a sample of Israeli military conscripts (perhaps because of individuals with earlier onset schizophrenia, “which has a higher sibling recurrence”).
Bipolar disorder showed a similar pattern of association but of a lesser magnitude, study results indicate.
http://www.futurity.org/health-medicine/autism-and-schizophrenia-may-share-root-cause/
The ‘autism epidemic’ and diagnostic substitution
Excellent article on the question of why there’s been such an increase in autism diagnoses. The researcher makes a strong case that it is because of changes in diagnosis rather than a true increase.
http://deevybee.blogspot.com/2012/06/autism-epidemic-and-diagnostic.html
Oxytocin improves brain function in children with autism
Preliminary results from an ongoing, large-scale study shows that oxytocin increased brain function in regions that are known to process social information in children and adolescents with autism spectrum disorders.
http://www.eurekalert.org/pub_releases/2012-05/yu-oib051812.php
Research shows how PCBs promote dendrite growth, may increase autism risk
New research shows that PCBs, or polychlorinated biphenyls, launch a cellular chain of events that leads to an overabundance of dendrites and disrupts normal patterns of neuronal connections in the brain. "Impaired neuronal connectivity is a common feature of a number of conditions, including autism spectrum disorders." It’s suggested that PCB exposure "may increase the likelihood of autism in children whose genetic makeup already compromises the processes by which neurons form connections."
http://www.eurekalert.org/pub_releases/2012-04/uoc--rsh042512.php
http://www.futurity.org/health-medicine/toxic-pcbs-scramble-brain-connections/
Full text available at http://ehp03.niehs.nih.gov/article/info%3Adoi%2F10.1289%2Fehp.1104833
Protein in overdrive links to autism
March 21, 2012
A mouse study suggests that early disruptions in serotonin signaling in the brain may contribute to autism spectrum disorder. It has long been known that many children with autism have elevated blood levels of serotonin (hyperserotonemia).
http://www.futurity.org/health-medicine/serotonin-in-overdrive-links-to-autism/
People with autism possess greater ability to process information, study suggests
A small study suggests that people with autism spectrum disorders have a greater than normal capacity for processing perceptual information even from rapid presentations and are better able to detect information defined as 'critical'.
http://www.eurekalert.org/pub_releases/2012-03/wt-pwa032212.php
Autism mutations, scattered across many genes, merge into common network of interactions
A large study looking at the genes of children with sporadic autism" (no family history) has found that many mutations related to modifying chromatin (the tightly coiled spools of DNA in the cell), changing the way DNA is packaged. They also found that new mutations were overwhelming paternal in origin (in a ratio of 4:1), that the new mutations occurred at a rate that correlated with the age of the father.
What is also very clear from this and other recent studies is that autism risk mutations are scattered across many genes. It’s suggested that although no single gene will account for more than 1% of autism cases, collectively all of these rare mutations will account for much of the genetic basis of the disease.
http://www.eurekalert.org/pub_releases/2012-04/uow-ams040212.php
Evolution's gift may also be at the root of a form of autism
May 10th, 2012
A study has identified the evolutionary changes that led the NOS1 gene to become active specifically in the parts of the developing human brain that form the adult centers for speech and language and decision-making. This pattern of NOS1 activity is controlled by a protein called FMRP and is missing in Fragile X syndrome. Fragile X syndrome, the leading inherited form of intellectual disability, is also the most common single-gene cause of autism.
http://medicalxpress.com/news/2012-05-evolution-gift-root-autism.html
Researchers discover new genes contributing to autism, links to psychiatric disorders
April 19th, 2012
A new approach to investigating hard-to-find chromosomal abnormalities has identified 33 genes associated with autism and related disorders, 22 for the first time. Several of these genes also appear to be altered in different ways in individuals with psychiatric disorders such as schizophrenia.
http://medicalxpress.com/news/2012-04-genes-contributing-autism-links-psychiatric.html
RNA discovery offers clue in autism puzzle
April 5, 2012
Scientists have discovered the first gene associated with autism that has genome-wide significance. Expression of MSNP1AS was increased 12-fold in the brains of people with autism. This gene controls expression of a protein called moesin, which influences brain development and immune response.
http://www.futurity.org/health-medicine/rna-discovery-offers-clue-in-autism-puzzle/
Study identifies gene expression abnormalities in autism
March 22nd, 2012
Following previous research showing a link between autism and excess brain cells in the prefrontal cortex, a study has showed that genetic mechanisms that normally regulate the number of cortical neurons are abnormal in such cases. This abnormality may not only result in too many neurons in some regions, but not enough in others.
Moreover, while the adolescent prefrontal cortex showed dysregulation in the pathways that govern cell number, cortical patterning and cell differentiation, adults showed dysregulation of signaling and repair pathways — indicating that gene expression abnormalities change across the lifespan in autism.
http://medicalxpress.com/news/2012-03-gene-abnormalities-autism.html
With autism, altered white matter in brain
March 7, 2012
Brain imaging and computer modeling shows how autistic brains tend to have poor quality white matter tracts connecting the frontal and posterior regions of the brain. This may explain social and language impairments.
This may mean that appropriate training could improve the white matter — compromised white matter in children with reading difficulties has been shown to be reparable with extensive behavioral therapy.
http://www.futurity.org/health-medicine/with-autism-altered-white-matter-in-brain/
Autism can be detected in babies, say scientists
A study involving six- to 10-month-old babies who had an older brother or sister with autism found that brain activity while the infants were shown faces that switched between looking at them or away from them was indicative of later diagnoses of autism.
http://www.guardian.co.uk/society/2012/jan/27/autism-detected-babies-say-scientists
http://www.eurekalert.org/pub_releases/2012-01/cp-itb012012.php
Neuroscientists find that two rare autism-related disorders are caused by opposing malfunctions in the brain
November 24, 2011
Most cases of autism are not caused by a single genetic mutation. However, several disorders with autism-like symptoms, including the rare Fragile X syndrome, can be traced to a specific mutation that leads to overproduction of proteins found in brain synapses. A new study shows that tuberous sclerosis, another rare disease characterized by autism and mental retardation, is caused by the opposite malfunction — too little synthesis of those synaptic proteins.
The findings fit into the theory that autism can be caused by a wide range of brain-synapse glitches. “The general concept is that appropriate brain function occurs within a very narrow physiological range that is tightly maintained. If you exceed that range in either direction, you have an impairment that can manifest as this constellation of symptoms, which very frequently go together — autism spectrum disorder, intellectual disability and epilepsy.”
The findings also show that not all cases of autism spectrum disorder will respond to the same kind of treatment.
http://medicalxpress.com/news/2011-11-neuroscientists-rare-autism-related-disorders-opposing.html
Research reveals autistic individuals are in fact superior in multiple areas
Articles about neurocentrism etc
http://medicalxpress.com/news/2011-11-reveals-autistic-individuals-fact-superior.html
http://www.nature.com/nature/journal/v479/n7371/full/479033a.html
http://www.nature.com/nature/journal/v479/n7371/full/479005a.html
http://www.guardian.co.uk/science/neurophilosophy/2011/oct/07/1
http://www.scientificamerican.com/article.cfm?id=the-hidden-potential-of-autistic-kids
Researchers find alterations of a single gene associated with intellectual disability, epilepsy and autistic features
October 7, 2011
A study has identified the gene MBD5 as the sole causative gene for 2q23.1 deletion syndrome. MBD5 functions in regulating the expression of many genes and is responsible for the core clinical features in these individuals, including intellectual disability, epilepsy and autism spectrum disorder. They have also shown that there is an association between autism and MBD5.
http://medicalxpress.com/news/2011-10-gene-intellectual-disability-epilepsy-autistic.html
New evidence for genetic basis of autism found
October 3, 2011
Some children with autism have a small deletion on chromosome 16, affecting 27 genes in a region of our genomes referred to as 16p11.2. The deletion -- which causes children to inherit only a single copy of the 27-gene cluster -- is one of the most common copy number variations (CNVs) associated with autism. A new study has found that deleting this set of genes in mice produces autistic-like behaviors: hyperactivity, difficulty adapting to a new environment, sleeping deficits, and restricted, repetitive behaviors.
http://medicalxpress.com/news/2011-10-evidence-genetic-basis-autism.html
Prenatal SSRI Exposure Linked to Autism Spectrum Disorder
A study suggests that use of selective serotonin reuptake inhibitors (SSRIs) during pregnancy increases the risk of autism spectrum disorder.
http://dx.doi.org/10.1001/archgenpsychiatry.2011.73
Inflexibility may give pupils with autism problems in multitasking
A study finds that young people with autism are inflexible when given multiple tasks, sticking rigidly to tasks in the order they are given to them, even when changing the order could save them time. They also had more difficulty remembering all the tasks they had to do.
http://www.eurekalert.org/pub_releases/2011-08/uos-img081511.php
The Risk of Aging Fathers
August 30, 2011
A mouse study has found that older males sire offspring with more copy number mutations in gene regions associated with developmental disorders, perhaps explaining why the children of older men have higher rates of schizophrenia and autism than those with younger fathers.
http://the-scientist.com/2011/08/30/the-risk-of-aging-fathers/
Diagnosed autism is more common in an IT-rich region
June 20, 2011
A Dutch study comparing prevalence of autism spectrum disorders in three geographical regions has found that diagnosed autism was significantly higher conditions in the IT-intensive region of Eindhoven (229 per 10,000, vs 84 per 10,000 and 57 per 10,000 in IT-lower regions — Haarlem and Utrecht).
http://medicalxpress.com/news/2011-06-autism-common-it-rich-region.html
Balance tips toward environment as heritability ebbs in autism?
July 4, 2011
A large twin study found that shared environmental factors accounted for 55% of strict autism and 58% of more broadly defined autism spectrum disorders (ASD). Genetic heritability accounted for 37% of autism and 38% of ASD. This dramatically reduces previous estimates of genetic heritability of autism from twin studies.
http://medicalxpress.com/news/2011-07-environment-heritability-ebbs-autism.html
Gene linked to severity of autism's social dysfunction
April 6, 2011
Variants in the gene GRIP1 (glutamate receptor interacting protein 1) have been found to contribute to the severity of social interaction deficits in autistic individuals. This gene regulates how fast receptors travel to a cell's surface, where they are activated by a brain-signaling chemical called glutamate, allowing neurons to communicate with one another. The finding lends support to a prevailing theory that autism spectrum disorders reflect an imbalance between inhibitory and excitatory signaling at synapses.
http://www.physorg.com/news/2011-04-gene-linked-severity-autism-social.html
Why Autism Strikes More Boys Than Girls
July 19, 2011
The marked gender imbalance in autism may related to a gene called retinoic acid–related orphan receptor-alpha (RORA), which interacts with certain types of estrogen and testosterone found in the brain. Autistic individuals tend to have low levels of RORA protein and the enzyme it produces (aromatase). This enzyme converts testosterone to estrogen, but RORA is less active in the presence of testosterone made RORA, and more active in the presence of estrogen. While the balance of sex hormones usually regulates RORA activity, an imbalance can be exacerbated by this feedback loop.
It’s suggested that low levels of RORA protein and enzyme result in an excess of testosterone, while most females are protected by their higher levels of estrogen.
http://www.scientificamerican.com/article.cfm?id=why-autism-strikes-more-boys-than-girls
'Most adults with autism go undiagnosed' -- new findings
The first ever general population survey of autism in adulthood has found that 9.8 per thousand adults in England meet official diagnostic criteria for autism spectrum disorder. Moreover, none of the cases with autism found knew that they were autistic or had received an official diagnosis of autism or asperger syndrome. The findings add support to the theory that autism is not increasing, diagnosis is just more common.
http://www.eurekalert.org/pub_releases/2011-05/uol-aw050411.php
Autism linked to hundreds of spontaneous genetic mutations
June 9. 2011
The most comprehensive search yet for spontaneous genetic mutations associated with autism spectrum disorders suggests that hundreds may play a part. It also finds that girls with autism tend to have many more mutated genes than boys with the disorder, suggesting that it generally takes a larger genomic change to cause autism in girls.
A particularly interesting finding was that, while deletion of a segment of chromosome 7 (specifically, 7q11.23) is associated with Williams Syndrome (marked by hypersocial behavior), duplication of this region is associated with autism.
http://www.nature.com/news/2011/110609/full/news.2011.359.html
http://medicalxpress.com/news/2011-06-genetic-keys-autism.html
http://www.scientificamerican.com/article.cfm?id=autism-genetic-mutations
How common is autism?
Great discussion of why prevalence estimates can be so different, and why diagnosing autism spectrum disorders is so difficult.
http://www.guardian.co.uk/science/blog/2011/jun/07/how-common-autism-diagnosis
Mapping data shows enhanced activity in the 'perception' part of the brain
Brain scans have determined that people with autism concentrate more brain resources in the areas associated with visual detection and identification (temporal, occipital, and parietal lobes), and conversely, have less activity in the areas used to plan and control thoughts and actions (frontal lobe).
http://www.eurekalert.org/pub_releases/2011-04/uom-nre032811.php
An autism brain signature?
May 25, 2011
A genome-wide analysis of the RNA in the brains of individuals with autism has revealed that, while gene expression in the frontal lobe normally varies significantly from that in the temporal lobe due to their different functions, this tended not to be true of autistic brains. Instead, in more than 2/3 autistic individuals, the levels of gene expression between the two lobes were homogenized, as if they had similar functions.
http://www.the-scientist.com/?articles.view/articleNo/29713/title/An-autism-brain-signature-/
New Genetics Work Challenges Basic Ideas about Mental Illness
May 17, 2011
Some background on genetic mutations — explaining single-nucleotide polymorphisms (SNPs), copy-number variants (CNVs), genome-wide association studies (GWAS), and how they’re being used in research into the causes of various disorders.
http://www.scientificamerican.com/article.cfm?id=new-genetics-work-challenges-basic-ideas-about-mental-illness
Researchers link spontaneous gene mutations to autism
May 16, 2011
Preliminary results suggest that as many as % of sporadic autism cases can be explained by spontaneous gene mutations. The findings are also consistent with other studies suggesting that ASDs are more likely in children born to older parents, and in particular, older fathers.
http://medicalxpress.com/news/2011-05-link-spontaneous-gene-mutations-autism.html
Children conceived in winter have a greater risk of autism, study finds
May 5, 2011
An examination of the birth records of children born in California during the 1990s and early 2000s has found a clear link between the month in which a child is conceived and the risk of that child later receiving a diagnosis of autism, with those conceived during winter having a significantly greater risk of autism.
Earlier studies (all much smaller) have found inconsistent results in linking autism risk to month of conception.
http://medicalxpress.com/news/2011-05-children-winter-greater-autism.html
The mirror neuron system in autism: Broken or just slowly developing?
May 3, 2011
It’s been suggested that the mirror neuron system (neurons that activate in similar ways whether we perform actions or watch other people perform the same actions) is broken in autistic individuals, but a new study suggests that it just develops more slowly.
http://medicalxpress.com/news/2011-05-mirror-neuron-autism-broken-slowly.html
An interview with mirror neuron guru Vilayanur S. Ramachandran about autism and mirror neurons.
http://scienceblogs.com/neurophilosophy/2011/03/ramachandran_broken_mirror.php
A world first: The discovery of a common genetic cause of autism and epilepsy
April 8, 2011
Researchers have identified a new gene that predisposes people to both autism and epilepsy. The synapsin gene (SYN1) plays a crucial role in the development of the membrane surrounding neurotransmitters (the synaptic vesicles), affecting communication between neurons.
http://www.physorg.com/news/2011-04-world-discovery-common-genetic-autism.html
Knowing Me, Knowing You: How Social Intuition Goes Awry in Autism
March 7, 2011
It’s suggested that the social impairment characteristic of autism spectrum disorders may be related to a lack of a type of spindle neurons called Von Economo neurons. These neurons are only found in very social species, such as the great apes, elephants, and whales and dolphins, and are found only in the frontoinsular and anterior cingulate cortex.
http://www.scientificamerican.com/article.cfm?id=knowing-me-knowing-you
Cognitive skills in children with autism vary and improve, study finds
September 15, 2010
A three year study looking at how the cognitive skills of children with ASD change over time has found that most of the children (aged 5-6 at the beginning of the study) developed better appreciation of others' thoughts and feelings, and improved ability to plan, regulate, and control their thoughts and actions. However, their ability to construct patterns from wooden blocks and search for shapes hidden in pictures did not improve over time.
www.physorg.com/news203744311.html
Too Much, Too Young: Brain Overgrowth Correlates with the Severity of Autism Symptoms
July 27, 2010
Excess brain growth may be the first sign of autism, starting in the first year of life, if not sooner.
http://www.scientificamerican.com/article.cfm?id=too-much-too-young
Scientists have the genetic causes of autism in their sights
The Autism Genome Project has identified rare genetic mutations (copy number variations (CNVs)), that were 20% more frequent in children with autism than in children without the disorder.
http://www.guardian.co.uk/science/2010/jun/09/autism-study-genetic-causes
http://www.eurekalert.org/pub_releases/2010-06/uoc--wld060710.php
Alternative Biomedical Treatments for Autism: How Good Is the Evidence?
October 7, 2010
Review of alternative autism treatments.
http://www.scientificamerican.com/article.cfm?id=alternative-biomedical-treatments
A Crack in the Mirror Neuron Hypothesis of Autism
May 12, 2010
A new test of mirror neuron activity suggests that autistic individuals’ mirror neurons may behave normally. However, they showed more variable activity in brain regions that process visual images and execute movements. The researchers suggest that it may be faulty signaling, rather than mirror neuron problems, that underlies some of their social difficulties.
The researchers’ tests and interpretations are controversial.
http://news.sciencemag.org/sciencenow/2010/05/a-crack-in-the-mirror-neuron-hyp.html?etoc
Video Q&A: What is autism? - A personal view
http://www.biomedcentral.com/1741-7007/8/42
Stem cells restore cognitive abilities impaired by brain tumor treatment
A rat study has found that transplanted stem cells restored learning and memory to normal levels four months after radiotherapy. This compares with a greater than 50% decline in cognitive function in those rats that didn’t receive the therapy. Cranial irradiation is a common treatment for brain tumors.
[803] Acharya, M. M., Christie L. - A., Lan M. L., Donovan P. J., Cotman C. W., Fike J. R., et al.
(2009). Rescue of radiation-induced cognitive impairment through cranial transplantation of human embryonic stem cells.
Proceedings of the National Academy of Sciences. 106(45), 19150 - 19155.
http://www.eurekalert.org/pub_releases/2009-11/uoc--scr110509.php
Childhood brain tumors permanently impact cognition & lifestyle
A survey involving 785 CNS cancer survivors, 5,870 survivors of non-CNS cancers (such as leukemia, Hodgkin's disease, and bone tumors), and 379 siblings of CNS cancer survivors, sent at least 16 years after diagnosis, has found that CNS cancer survivors reported significantly greater neurocognitive dysfunction than their siblings and survivors of other types of cancer. Moreover, these problems were linked to lower achievement in education and in full-time employment and income, as well as less chance of being married. The worst problems were found in those who had tumors in the cortex, and those who had cranial radiation treatment.
Ellenberg, L. et al. 2009. Neurocognitive Status in Long-Term Survivors of Childhood CNS Malignancies: A Report From the Childhood Cancer Survivor Study. Neuropsychology, 23 (6), 705-717.
http://www.eurekalert.org/pub_releases/2009-11/apa-bti102709.php
Therapy program has significant effect on autistic toddlers
A randomized controlled trial involving autistic toddlers aged 18 to 30 months has found that those who participated for two years in an intensive program of behavioral therapy known as the Early Start Denver Model improved 17.6 standard score points in IQ, on average, compared with 7 points in the group who received standard community intervention. They were also more likely to be re-diagnosed from autism to pervasive developmental disorder.
[1499] Dawson, G., Rogers S., Munson J., Smith M., Winter J., Greenson J., et al.
(2010). Randomized, Controlled Trial of an Intervention for Toddlers With Autism: The Early Start Denver Model.
Pediatrics. 125(1), e17-23 - e17-23.
http://www.newscientist.com/article/dn18221-treating-toddlers-for-autism-boosts-iq-later.html
Study finds autistics better at problem-solving
A study involving 15 autistics and 18 non-autistics, aged 14 to 36 and IQ-matched, has found that while both groups completed patterns in a complex problem-solving test (the widely-used Raven's Standard Progressive Matrices) with equal accuracy, the autistics responded significantly faster, and showed a different pattern of brain activity. Specifically, they showed increased activity in extrastriate areas, and decreased activity in the lateral prefrontal cortex and the medial posterior parietal cortex — suggesting visual processing mechanisms may play a more prominent role in reasoning in autistics. The differences between groups did not appear when participants performed a simpler pattern-matching task.
[555] Soulières, I., Dawson M., Samson F., Barbeau E. B., Sahyoun C. P., Strangman G. E., et al.
(2009). Enhanced visual processing contributes to matrix reasoning in autism.
Human Brain Mapping. 30(12), 4082 - 4107.
http://www.eurekalert.org/pub_releases/2009-06/uom-sfa061609.php
New genes implicated in autism; support new theory of cause
Research involving 104 large Middle Eastern families has implicated half a dozen new genes in autism, and more importantly, strongly supports the emerging idea that autism stems from disruptions in the brain's ability to form new connections in response to experience – consistent with autism's onset during the first year of life, when many of these connections are normally made. Just over 6% of the 88 families with autistic members showed rare, inherited deletions within DNA regions linked to autism. These affected DNA regions varied among families, further indication of autism's large variety of genetic causes. In all, the technique identified five chromosome deletions affecting at least six identifiable genes. Although the genes discovered are diverse in function, all seem to be part of a fundamental network that orchestrates the refinement and maturation of synapses in response to input from the outside world. The network itself is already known to activate at least 300 genes, so it’s no surprise that there are many ways it can be disrupted, explaining why there might be myriad genetic causes of autism, even though in essence it might be all the same problem: a disruption of the brain's ability to modify its synaptic connections in response to experience. The good news is that in all but one case the chromosome deletions didn’t actually remove a gene, they just turned it off — suggesting a possible ‘cure’ if researchers can figure out how to turn them back on.
[942] Hashmi, A., Al-Saad S., Ware J., Joseph R. M., Greenblatt R., Gleason D., et al.
(2008). Identifying Autism Loci and Genes by Tracing Recent Shared Ancestry.
Science. 321(5886), 218 - 223.
http://www.eurekalert.org/pub_releases/2008-07/chb-mef070808.php
Autism's social struggles due to disrupted communication networks in brain
And a timely imaging study has now provided the clearest evidence to date that synchronization in what might be termed the Theory of Mind network is impaired in autistic people. The Theory of Mind network (which includes the medial frontal gyrus, the anterior paracingulate, and the right temporoparietal junction) is responsible for processing the intentions and thoughts of others. In the study 12 high-functioning autistic adults and 12 controls viewed animated interacting geometric figures, and then asked to select the word from several choices that best described the interaction. The control subjects were consistently better at inferring the intention from the action than the participants with autism were. Brain scans revealed that synchronization between the frontal and posterior regions in the network was reliably lower in the group with autism. The autistic participants' brains also showed much lower activation levels in the frontal regions, and an independent assessment of their Theory of Mind abilities found these reliably correlated with activation in the right temporoparietal junction. The findings point to the need to develop interventions that could target this problem, and also indicate a way to measure an intervention’s effectiveness.
[782] Kana, R. K., Keller T. A., Cherkassky V. L., Minshew N. J., & Just M A.
(2009). Atypical frontal-posterior synchronization of Theory of Mind regions in autism during mental state attribution.
Social Neuroscience. 4(2), 135 - 152.
http://www.eurekalert.org/pub_releases/2008-07/cmu-ass072308.php
New genetic link to autism identified
Three new studies, using different methods, have all implicated the same gene in the development of autism. The research follows earlier findings implicating a specific region of Chromosome 7 called 7q35. The gene — contactin-associated protein-like 2 (CNTNAP2) — is a gene in this region. The research not only points to this gene predisposing an individual to autism, it also may explain the association with late language onset, a characteristic of most autistic children. The gene was most active in developing brain structures involved in language and thought. The finding may also help explain why autism is so much more common among boys. Statistical evidence for the gene was strongest in families with autistic boys. Less of an association appeared in families with autistic boys and girls, or in families with autistic girls only.
[902] Ledbetter, D. H., Alarcón M., Abrahams B. S., Stone J. L., Duvall J. A., Perederiy J. V., et al.
(2008). Linkage, Association, and Gene-Expression Analyses Identify CNTNAP2 as an Autism-Susceptibility Gene.
The American Journal of Human Genetics. 82(1), 150 - 159.
[538] Cook Jr., E. H., Arking D. E., Cutler D. J., Brune C. W., Teslovich T. M., West K., et al.
(2008). A Common Genetic Variant in the Neurexin Superfamily Member CNTNAP2 Increases Familial Risk of Autism.
The American Journal of Human Genetics. 82(1), 160 - 164.
[857] Stillman, A. A., Bakkaloglu B., O'Roak B. J., Louvi A., Gupta A. R., Abelson J. F., et al.
(2008). Molecular Cytogenetic Analysis and Resequencing of Contactin Associated Protein-Like 2 in Autism Spectrum Disorders.
The American Journal of Human Genetics. 82(1), 165 - 173.
http://www.eurekalert.org/pub_releases/2008-01/uoc--usi010808.php
Autism non-verbal not unintelligent
New findings suggest that the association of autism with low intelligence is a product of their language difficulties. Testing autistic kids and normal kids on two popular IQ tests — the WISC (which relies heavily on language) and Raven's Progressive Matrices (considered the best test of "fluid intelligence", and a test that doesn't require much language) found that while not a single autistic child scored in the "high intelligence" range of the WISC, a third did on the Raven's. A third of the autistics had WISC scores in the mentally retarded range, but only one in 20 scored that low on the Raven's test. The non-autistic children scored similarly on both tests. The same results occurred when the experiment was run on autistic and normal adults.
[580] Dawson, M., Soulières I., Gernsbacher M A., & Mottron L.
(2007). The level and nature of autistic intelligence.
Psychological Science: A Journal of the American Psychological Society / APS. 18(8), 657 - 662.
http://www.physorg.com/news105376203.html
http://www.eurekalert.org/pub_releases/2007-08/afps-tmo080307.php
Monkeys can reflect on their thoughts
A study involving two rhesus macaque monkeys has shown that a monkey can reflect on its own thoughts and assess its performance. The experiment trained the monkeys to play a video game that tested their ability to remember a particular photograph while also allowing them to make a large or a small bet on how likely they were to be right. The monkeys could also request hints for problems that would otherwise have to be solved by trial and error. Not only did the results provide clear evidence of their ability to engage in metacognition, but the study also points to a means of testing nonverbal humans, such an infants and autistic children.
[1315] Kornell, N., Son L. K., & Terrace H. S.
(2007). Transfer of metacognitive skills and hint seeking in monkeys.
Psychological Science: A Journal of the American Psychological Society / APS. 18(1), 64 - 71.
http://www.eurekalert.org/pub_releases/2007-04/afps-mat042007.php
Oxytocin may help treat two core autism symptoms
In a pilot study, researchers have found administration of oxytocin has beneficial effects on repetitive behaviors and aspects of social cognition in high-functioning autistic adults.
The research was presented at the American College of Neuropsychopharmacology's Annual Meeting.
http://www.eurekalert.org/pub_releases/2006-12/g-nrs120106.php
A gene for autism
A study has found that those with two copies of a specific variant of a gene within chromosome 7, that regulates production of a protein that influences cell proliferation in various parts of the body, are substantially more likely to be autistic. The link between the MET variant and autism appears primarily in families with two or more affected children. The gene variant is not rare — roughly 47% of the population carry at least one copy of it. It may be that it is affected by prenatal environmental factors or that it interacts with other genes to derail brain formation. It is likely that there are a number of genes associated with autism. But this particular gene variant would explain controversial reports that people with autism often have immune and gastrointestinal problems.
[692] Sacco, R., Persico A. M., Levitt P., Campbell D. B., Sutcliffe J. S., Ebert P. J., et al.
(2006). A genetic variant that disrupts MET transcription is associated with autism.
Proceedings of the National Academy of Sciences. 103(45), 16834 - 16839.
http://www.sciencenews.org/articles/20061021/fob1.asp
Brain enlargement may be characteristic of autism
Comparison of 164 children with autism and 214 control children (all younger than 3 years) has found significant enlargement in the volume of the cerebral cortex, in both white and grey matter, and generalized throughout the cortex. Head circumference was not significantly different at birth — an increased rate of growth occurred from around 12 months.
[315] Hazlett, H C., Poe M., Gerig G., Smith R G., Provenzale J., Ross A., et al.
(2005). Magnetic Resonance Imaging and Head Circumference Study of Brain Size in Autism: Birth Through Age 2 Years.
Arch Gen Psychiatry. 62(12), 1366 - 1376.
http://www.eurekalert.org/pub_releases/2005-12/jaaj-bem120105.php
Breakdown of myelin insulation in brain's wiring implicated in childhood developmental disorders
Previous research has suggested that the production of myelin (a fatty insulation coating the brain's internal wiring) is a key component of brain development through childhood and well into middle age, when development peaks and deterioration begins, and that midlife breakdown of myelin is implicated to onset of Alzheimer's disease later in life. Now new research suggests the disruption of myelination is a key neurobiological component behind childhood developmental disorders, such as autism and attention deficit/hyperactivity disorder, and addictive behaviors. The analysis also suggests that alcohol and other drugs of abuse have toxic effects on the myelination process in some adolescents.
Bartzokis, G. 2005. Adolescent Psychiatry. Hillsdale, N.J.: The Analytic Press Inc.
http://www.eurekalert.org/pub_releases/2005-11/uoc--bom111405.php
Why autism is associated with executive function problems
A new imaging study has revealed that autistic boys have less activation in the parts of the brain responsible for executive function (attention, reasoning and problem solving) — specifically, in the caudate nucleus, a critical part of circuits that link the prefrontal cortex of the brain. The researchers have noted similarities in the impairment of specific executive function in children with ADHD and autism.
[2574] Silk, T., Rinehart N., Bradshaw J., Tonge B., Egan G., O’Boyle M., et al.
(Submitted). Visuospatial Processing and the Function of Prefrontal-Parietal Networks in Autism Spectrum Disorders: A Functional MRI Study.
American Journal of Psychiatry. 163(8), 1440 - 1443.
http://www.eurekalert.org/pub_releases/2005-10/ra-ape102305.php
Finding supports theory that autism results from failure of brain areas to work together
An imaging study indicates people with autism remember letters as geometric shapes, compared to the more usual remembering by their names. Moreover, compared to the control group, the activated brain areas of the people with autism were less likely to work in synchrony (at the same time) while recalling the letters. This supports a theory that autism results from a failure of the various parts of the brain to work together. This theory suggests that therapies emphasizing problem solving skills and other tasks that activate multiple brain areas at the same time might benefit people with autism.
Koshino, H., Carpenter, P.A., Minshew, N.J., Cherkassky, V.L., Keller, T.A. & Just, M.A. 2005. Functional connectivity in an fMRI working memory task in high-functioning autism. NeuroImage, 24 (3), 810-821.
http://www.eurekalert.org/pub_releases/2004-11/nioc-bop112904.php
Special training may help people with autism recognize faces
People with autism tend to activate object-related brain regions when they are viewing unfamiliar faces, rather than a specific face-processing region. They also tend to focus on particular features, such as a mustache or a pair of glasses. However, a new study has found that when people with autism look at a picture of a very familiar face, such as their mother's, their brain activity is similar to that of control subjects – involving the fusiform gyrus, a region in the brain's temporal lobe that is associated with face processing, rather than the inferior temporal gyrus, an area associated with objects. Use of the fusiform gyrus in recognizing faces is a process that starts early with non-autistic people, but does take time to develop (usually complete by age 12). The study indicates that the fusiform gyrus in autistic people does have the potential to function normally, but may need special training to operate properly.
Aylward, E. 2004. Functional MRI studies of face processing in adolescents and adults with autism: Role of experience. Paper presented February 14 at the annual meeting of the American Association for the Advancement of Science in Seattle.
Dawson, G. & Webb, S. 2004. Event related potentials reveal early abnormalities in face processing autism. Paper presented February 14 at the annual meeting of the American Association for the Advancement of Science in Seattle.
http://www.eurekalert.org/pub_releases/2004-02/uow-stm020904.php
Autistic preschoolers don't recognize emotions from facial photographs
Normally developing infants notice their mothers' facial expressions and emotions in the first six months of life and are able to recognize emotions from facial expressions by age 7 months. In a recent study reported at the first International Meeting for Autism Research in San Diego last month, 3- and 4-year-old autistic, developmentally delayed and normally developing children were shown photographs of faces depicting fear and a neutral expression while brain activity was monitored. It was found that the brains of normally developing and developmentally delayed children exhibited different activity depending on the picture being viewed. However, the brain activity of the autistic children remained the same when the different pictures were shown.
Dawson, G. & Dager, S. 2001. Paper presented at the first International Meeting for Autism Research in San Diego in November. The autism meeting was held in conjunction with the annual meeting of the Society for Neuroscience.
http://www.eurekalert.org/pub_releases/2001-12/uow-ahl120401.php
Differences in face perception processing between autistic and normal adults
An imaging study compared activation patterns of adults with autism and normal control subjects during a face perception task. While autistic subjects could perform the face perception task, none of the regions supporting face processing in normals were found to be significantly active in the autistic subjects. Instead, in every autistic patient, faces maximally activated aberrant and individual-specific neural sites (e.g. frontal cortex, primary visual cortex, etc.), which was in contrast to the 100% consistency of maximal activation within the traditional fusiform face area (FFA) for every normal subject. It appears that, as compared with normal individuals, autistic individuals `see' faces utilizing different neural systems, with each patient doing so via a unique neural circuitry.
[704] Pierce, K., Muller R. - A., Ambrose J., Allen G., & Courchesne E.
(2001). Face processing occurs outside the fusiform `face area' in autism: evidence from functional MRI.
Brain. 124(10), 2059 - 2073.
http://brain.oupjournals.org/cgi/content/abstract/124/10/2059
Autistic 3- and 4-year-olds react to a picture of a familiar toy but not to a picture of their mother
Face recognition is a specialized and highly developed memory system in humans, and a preference for face-like stimuli is evident even in newborn babies. New research has found that, unlike normally developing and even mentally retarded children, autistic 3- and 4-year-olds do not react to a picture of their mother, although they do react when they see a picture of a familiar toy. This highlights that autism is a disorder of the social brain, and may allow diagnoses of autism to be made much earlier than is now possible.
The study was reported at the annual meeting of the Society for Research in Child Development.
http://www.eurekalert.org/pub_releases/2001-04/UoW-Mija-1604101.php