A genome-wide scan for common alleles affecting risk for autism.

Although autism spectrum disorders (ASDs) have a substantial genetic basis, most of the known genetic risk has been traced to rare variants, principally copy number variants (CNVs). To identify common risk variation, the Autism Genome Project (AGP) Consortium genotyped 1558 rigorously defined ASD families for 1 million single-nucleotide polymorphisms (SNPs) and analyzed these SNP genotypes for association with ASD. In one of four primary association analyses, the association signal for marker rs4141463, located within MACROD2, crossed the genome-wide association significance threshold of P < 5 × 10(-8).

Generative learning during visual search for scene changes: enhancing free recall of individuals with and without mental retardation.

Memory for scene changes that were identified immediately (passive encoding) or following systematic and effortful search (generative encoding) was compared across groups differing in age and intelligence. In the context of flicker methodology, generative search for the changing object involved selection and rejection of multiple potential solutions prior to identification of the correct object. Such "incorrect guesses" were designed to serve as effective retrieval cues during free recall.

Specifying PDD-NOS: a comparison of PDD-NOS, Asperger syndrome, and autism.

Objective: To describe the clinical characteristics of children given a diagnosis of pervasive developmental disorder-not otherwise specified (PDD-NOS) by expert clinicians and to compare these to the clinical characteristics of children given a diagnosis of autism and Asperger syndrome (AS).

Method: Two hundred sixteen children with autism, 33 with AS, and 21 with PDD-NOS were compared on measures of level of functioning (communication, daily living and social skills, IQ, and age of acquisition of language) and on various symptoms of autism (impaired communication and reciprocal social interaction and a preference for repetitive and stereotyped activities).

Results: In terms of level of functioning measures, the PDD-NOS children had scores that were between those of the children with autism and those of the children with AS.

Detection of changes in naturalistic scenes: comparisons of individuals with and without mental retardation.

Abilities of individuals with and without mental retardation to search for and detect salient changes to naturalistic scenes were investigated using the flicker paradigm. Located in areas of central or marginal interest, changes involved an object's color, shape, or presence. Individuals with mental retardation required more time to detect changes of all types, and the magnitude of the group difference was more pronounced for marginal-interest changes.

Guiding visual attention during acquisition of matching-to-sample.

Matching-to-sample skills are involved in language acquisition and the development of basic reading and counting abilities. The rapid, even errorless, induction of matching performances in young children and individuals with mental retardation was demonstrated here through the structuring of a visual array so as to promote detection of the relevant stimulus. Implications for theory and application are discussed.

Guided visual search in individuals with mental retardation.

The ability of individuals with mental retardation to focus on task-relevant elements of complex visual arrays and increase visual-search efficiency was investigated. Initial assessments of visual-search efficiency were conducted to identify pairs of features for the form and size dimensions for which each participant demonstrated serial search. Subsequently, color was added as a defining feature that could guide search to a subset of the elements in the array.