Behavior

New CDC Report on Prevalence of Autism Spectrum Disorders

Source: 
CDC- MMWR Surveillance Studies
Date Published: 
December 18, 2009
Abstract: 

In 2006, on average, approximately 1% or one child in every 110 in the 11 ADDM sites was classified as having an ASD. The average prevalence of ASDs identified among children aged 8 years increased 57% in 10 sites from the 2002 to the 2006 ADDM surveillance year. Although improved ascertainment accounts for some of the prevalence increases documented in the ADDM sites, a true increase in the risk for children to develop ASD symptoms cannot be ruled out. On average, although delays in identification persisted, ASDs were being diagnosed by community professionals at earlier ages in 2006 than in 2002.

Behavioral Training Improves Connectivity and Function in the Brain

Source: 
National Institute of Mental Health (NIMH)
Date Published: 
December 9, 2009
Abstract: 

Children with poor reading skills who underwent an intensive, six-month training program to improve their reading ability showed increased connectivity in a particular brain region, in addition to making significant gains in reading, according to a study funded in part by the National Institute of Mental Health (NIMH).

Reversal of Learning Deficits in a Ts2+/- Mouse Model of Tuberous Sclerosis

Source: 
Nature Medicine, Ehninger, Han, et al
Date Published: 
2008
Year Published: 
2008

Tuberous sclerosis is a single-gene disorder caused by heterozygous mutations in the TSC1 (9q34) or TSC2 (16p13.3) gene and is frequently associated with mental retardation, autism and epilepsy. Even individuals with tuberous sclerosis and a normal intelligence quotient (approximately 50%) are commonly affected with specific neuropsychological problems, including long-term and working memory deficits. Here we report that mice with a heterozygous, inactivating mutation in the Tsc2 gene (Tsc2(+/-) mice) show deficits in learning and memory. Cognitive deficits in Tsc2(+/-) mice emerged in the absence of neuropathology and seizures, demonstrating that other disease mechanisms are involved. We show that hyperactive hippocampal mammalian target of rapamycin (mTOR) signaling led to abnormal long-term potentiation in the CA1 region of the hippocampus and consequently to deficits in hippocampal-dependent learning. These deficits included impairments in two spatial learning tasks and in contextual discrimination. Notably, we show that a brief treatment with the mTOR inhibitor rapamycin in adult mice rescues not only the synaptic plasticity, but also the behavioral deficits in this animal model of tuberous sclerosis. The results presented here reveal a biological basis for some of the cognitive deficits associated with tuberous sclerosis, and they show that treatment with mTOR antagonists ameliorates cognitive dysfunction in a mouse model of this disorder.

Stereotypes and Hyperactivity in Rhesus Monkeys Exposed to IgG from Mothers of Children with Autism

Source: 
Brain Behavior Immunology, Martin, Ashwood, Braunschweig, Cabanlit, Van de Water, Amaral
Date Published: 
2008

One proposed cause of ASD is exposure of the fetal brain to maternal autoantibodies during pregnancy [Dalton, P., Deacon, R., Blamire, A., Pike, M., McKinlay, I., Stein, J., Styles, P., Vincent, A., 2003. Maternal neuronal antibodies associated with autism and a language disorder. Ann. Neurol. 53, 533-537]. To provide evidence for this hypothesis, four rhesus monkeys were exposed prenatally to human IgG collected from mothers of multiple children diagnosed with ASD. Four control rhesus monkeys were exposed to human IgG collected from mothers of multiple typically developing children. Five additional monkeys were untreated controls. Monkeys were observed in a variety of behavioral paradigms involving unique social situations. Behaviors were scored by trained observers and overall activity was monitored with actimeters. Rhesus monkeys gestationally exposed to IgG class antibodies from mothers of children with ASD consistently demonstrated increased whole-body stereotypies across multiple testing paradigms. These monkeys were also hyperactive compared to controls. Treatment with IgG purified from mothers of typically developing children did not induce stereotypical or hyperactive behaviors. These findings support the potential for an autoimmune etiology in a subgroup of patients with neurodevelopmental disorders. This research raises the prospect of prenatal evaluation for neurodevelopmental risk factors and the potential for preventative therapeutics.