1. Judson MC, Amaral DG, Levitt P. {{Conserved Subcortical and Divergent Cortical Expression of Proteins Encoded by Orthologs of the Autism Risk Gene MET}}. {Cereb Cortex};2010 (Dec 1)

Met receptor tyrosine kinase signaling regulates the growth and development of axons and may contribute to the wiring of cortical and limbic circuits in the rodent forebrain. Whether the orthologous MET receptor functions similarly in the developing primate forebrain is not known but is of considerable interest considering the association of variant MET alleles with social and communication phenotypes in autism. To begin addressing this question, we compared Met/MET protein expression in the developing mouse and rhesus macaque forebrain. There was a strong temporal conservation of expression during the time of rapid axon development and the onset of robust synapse formation. Expression patterns of Met/MET in limbic-related structures were almost identical between species. In marked contrast, there was highly divergent expression in the neocortex. In mouse, Met was broadly distributed throughout neocortex. In the macaque, robust MET expression was largely restricted to the posterior cingulate, inferior temporal, posterior parietal, and visual cortices, including face processing regions. The pattern is consistent with the importance of vision in the social repertoire of the primate. Collectively, these data suggest a conserved developmental function of the MET receptor in wiring together limbic and neocortical circuits that facilitate species-appropriate responses, including social behavior.

2. Landa RJ, Holman KC, O’Neill AH, Stuart EA. {{Intervention targeting development of socially synchronous engagement in toddlers with autism spectrum disorder: a randomized controlled trial}}. {J Child Psychol Psychiatry};2010 (Dec 3)

Background: Social and communication impairments are core deficits and prognostic indicators of autism. We evaluated the impact of supplementing a comprehensive intervention with a curriculum targeting socially synchronous behavior on social outcomes of toddlers with autism spectrum disorders (ASD). Methods: Fifty toddlers with ASD, ages 21 to 33 months, were randomized to one of two six-month interventions: Interpersonal Synchrony or Non-Interpersonal Synchrony. The interventions provided identical intensity (10 hours per week in classroom), student-to-teacher ratio, schedule, home-based parent training (1.5 hours per month), parent education (38 hours), and instructional strategies, except the Interpersonal Synchrony condition provided a supplementary curriculum targeting socially engaged imitation, joint attention, and affect sharing; measures of these were primary outcomes. Assessments were conducted pre-intervention, immediately post-intervention, and, to assess maintenance, at six-month follow-up. Random effects models were used to examine differences between groups over time. Secondary analyses examined gains in expressive language and nonverbal cognition, and time effects during the intervention and follow-up periods. Results: A significant treatment effect was found for socially engaged imitation (p = .02), with more than doubling (17% to 42%) of imitated acts paired with eye contact in the Interpersonal Synchrony group after the intervention. This skill was generalized to unfamiliar contexts and maintained through follow-up. Similar gains were observed for initiation of joint attention and shared positive affect, but between-group differences did not reach statistical significance. A significant time effect was found for all outcomes (p < .001); greatest change occurred during the intervention period, particularly in the Interpersonal Synchrony group. Conclusions: This is the first ASD randomized trial involving toddlers to identify an active ingredient for enhancing socially engaged imitation. Adding social engagement targets to intervention improves short-term outcome at no additional cost to the intervention. The social, language, and cognitive gains in our participants provide evidence for plasticity of these developmental systems in toddlers with ASD. http://www.clinicaltrials.gov/ct2/show/NCT00106210?term = landa&rank = 3.

3. Lange N, Dubray MB, Lee JE, Froimowitz MP, Froehlich A, Adluru N, Wright B, Ravichandran C, Fletcher PT, Bigler ED, Alexander AL, Lainhart JE. {{Atypical diffusion tensor hemispheric asymmetry in autism}}. {Autism Res};2010 (Dec 2)

Background: Biological measurements that distinguish individuals with autism from typically developing individuals and those with other developmental and neuropsychiatric disorders must demonstrate very high performance to have clinical value as potential imaging biomarkers. We hypothesized that further study of white matter microstructure (WMM) in the superior temporal gyrus (STG) and temporal stem (TS), two brain regions in the temporal lobe containing circuitry central to language, emotion, and social cognition, would identify a useful combination of classification features and further understand autism neuropathology. Methods: WMM measurements from the STG and TS were examined from 30 high-functioning males satisfying full criteria for idiopathic autism aged 7-28 years and 30 matched controls and a replication sample of 12 males with idiopathic autism and 7 matched controls who participated in a previous case-control diffusion tensor imaging (DTI) study. Language functioning, adaptive functioning, and psychotropic medication usage were also examined. Results: In the STG, we find reversed hemispheric asymmetry of two separable measures of directional diffusion coherence, tensor skewness, and fractional anisotropy. In autism, tensor skewness is greater on the right and fractional anisotropy is decreased on the left. We also find increased diffusion parallel to white matter fibers bilaterally. In the right not left TS, we find increased omnidirectional, parallel, and perpendicular diffusion. These six multivariate measurements possess very high ability to discriminate individuals with autism from individuals without autism with 94% sensitivity, 90% specificity, and 92% accuracy in our original and replication samples. We also report a near-significant association between the classifier and a quantitative trait index of autism and significant correlations between two classifier components and measures of language, IQ, and adaptive functioning in autism.

4. McAleer P, Kay JW, Pollick FE, Rutherford MD. {{Erratum to: Intention Perception in High Functioning People with Autism Spectrum Disorders Using Animacy Displays Derived from Human Actions}}. {J Autism Dev Disord};2010 (Dec 3)

5. Tsatsanis KD, Noens IL, Illmann CL, Pauls DL, Volkmar FR, Schultz RT, Klin A. {{Managing Complexity: Impact of Organization and Processing Style on Nonverbal Memory in Autism Spectrum Disorders}}. {J Autism Dev Disord};2010 (Dec 3)

The contributions of cognitive style and organization to processing and recalling a complex novel stimulus were examined by comparing the Rey Osterrieth Complex Figure (ROCF) test performance of children, adolescents, and adults with ASD to clinical controls (CC) and non-impaired controls (NC) using the Developmental Scoring System. The ROCF task involves a complex structure with strong organizational or integrative processing demands. The individuals with ASD relied on a predominantly part-oriented strategy to cope with the complexity of the task and did not make the typical developmental shift to a configurational approach. Both processing style and organization (whether pieces of information were perceived as connected to one another in a meaningful way) contributed to structural recall in the ASD group.