We compared the cortical inputs to the superficial and deep compartments of the superior colliculus, asking if the corticotectal system, like the colliculus itself, consists of two functional divisions: visual and visuomotor. We made injections of retrograde tracer extending into both superficial and deep layers in three colliculi: the injection site involved mainly the upper quadrant representation in one case, the lower quadrant representation in a second case, and both quadrants in a third. In a fourth colliculus, the tracer injection was restricted to the lower quadrant representation of the superficial layers. After injections involving both superficial and deep layers, labeled cells were seen over V1, many prestriate visual areas, and in prefrontal and posterior parietal cortex. Both the density of labeled cells and the degree of visuotopic order as inferred from the distribution of labeled cells in cortex varied among areas. In visual areas comprising the lower levels of the cortical hierarchy, visuotopy was preserved, whereas in "higher" areas the distribution of labeled cells did not strongly reflect the visuotopic location of the injection. Despite the widespread distribution of labeled cells, there were several areas with few or no labeled cells: MSTd, 7a, VIP, MIP, and TE. In the case with an injection restricted to superficial layers, labeled cells were seen only in V1 and in striate-recipient areas V2, V3, and MT. The results are consistent with the idea that the corticotectal system consists of two largely nonoverlapping components: a visual component consisting of striate cortex and striate-recipient areas, which projects only to the superficial layers, and a visuomotor component consisting of many other prestriate visual areas as well as frontal and parietal visuomotor areas, which projects to the deep compartment of the colliculus.

Although autism spectrum disorder (ASD) can be reliably detected in the second year of life, the average age of diagnosis is 4 to 5 years. Limitations in access to timely ASD diagnostic evaluations delay enrollment in interventions known to improve developmental outcomes. As such, developing and testing streamlined methods for ASD diagnosis is a public health and research priority. In this report, we describe the Early Autism Evaluation (EAE) Hub system, a statewide initiative for ASD screening and diagnosis in the primary care setting. Development of the EAE Hub system involved geographically targeted provision of developmental screening technical assistance to primary care, community outreach, and training primary care clinicians in ASD evaluation. At the EAE Hubs, a standard clinical pathway was implemented for evaluation of children, ages 18 to 48 months, at risk for ASD. From 2012 to 2018, 2076 children were evaluated (mean age: 30 months; median evaluation wait time: 62 days), and 33% of children received a diagnosis of ASD. Our findings suggest that developing a tiered system of developmental screening and early ASD evaluation is feasible in a geographic region facing health care access problems. Through targeted delivery of education, outreach, and intensive practice-based training, large numbers of young children at risk for ASD can be identified, referred, and evaluated in the local primary care setting. The EAE Hub model has potential for dissemination to other states facing similar neurodevelopmental health care system burdens. Implementation lessons learned and key system successes, challenges, and future directions are reviewed.

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