Vision First? The Development of Primary Visual Cortical Networks Is More Rapid Than the Development of Primary Motor Networks in Humans

The development of cortical functions and the capacity of the mature brain to learn are largely determined by the establishment and maintenance of neocortical networks. Here we address the human development of long-range connectivity in primary visual and motor cortices, using well-established behavioral measures - a Contour Integration test and a Finger-tapping task - that have been shown to be related to these specific primary areas, and the long-range neural connectivity within those. Possible confounding factors, such as different task requirements (complexity, cognitive load) are eliminated by using these tasks in a learning paradigm. We find that there is a temporal lag between the developmental timing of primary sensory vs. motor areas with an advantage of visual development; we also confirm that human development is very slow in both cases, and that there is a retained capacity for practice induced plastic changes in adults. This pattern of results seems to point to human-specific development of the “canonical circuits” of primary sensory and motor cortices, probably reflecting the ecological requirements of human life

OCRIPLASMIN FOR VITREOMACULAR TRACTION IN CLINICAL PRACTICE: The INJECT Study.

Randomized clinical trials have demonstrated the safety and efficacy of ocriplasmin in patients with vitreomacular traction (VMT), including those with macular hole (MH). The INJECT study prospectively evaluated ocriplasmin in the setting of clinical practice. INJECT was a Phase 4, multicenter, prospective observational study. Patients were followed up for 12 months. Assessments included nonsurgical VMT resolution, nonsurgical MH closure, best-corrected visual acuity, occurrence of vitrectomy, and adverse events. The efficacy population (N = 395) received an ocriplasmin injection and had optical coherence tomography-confirmed VMT at baseline. At Day 28, the rate of nonsurgical VMT resolution was 40.7% in the overall group, and the rate of nonsurgical MH closure was 36.0% in the VMT with MH group. At Month 12, the rate of ≥2-line best-corrected visual acuity gain (irrespective of vitrectomy) was 36.8% in the overall group and 59.6% in the VMT with MH group. The percentage of patients who underwent vitrectomy in the study eye was 29.1% in the overall group and 55.6% in the VMT with MH group. Photopsia (9.8%) and vitreous floaters (6.8%) were the most frequent adverse events. The INJECT study showed that ocriplasmin is effective in a clinical setting in patients with VMT, with or without MH. No new safety signals were identified from this large and surgeon-selected patient group, although the significant limitations of the study design without an image reading center and scheduled study visit timings should be noted

Reticular drusen associated with geographic atrophy in age-related macular degeneration

PURPOSE: To characterize reticular drusen (RDR) in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) in a prospective, multicenter, natural history study. METHODS: Confocal scanning laser ophthalmoscopy (cSLO) three-field fundus autofluorescence (FAF; exc., 488; em., 500-700 nm), near-infrared reflectance (IR; 820 nm), and blue reflectance (BR; 488 nm) images as well as red-free (RF) and color fundus (CF) camera photographs were recorded in 458 GA patients. The digital images were evaluated by two independent readers with subsequent senior reader arbitration for prevalence and topographic distribution of RDR using a modified Early Treatment Diabetic Retinopathy Study grid. RESULTS: RDR were detected with at least one cSLO modality in 286 of 458 (62%) patients in either eye (bilateral 207 [45%]) and were visible in fundus camera photographs in 66 of 371 (18%) patients (bilateral 48 [13%]). Prevalence of RDR by cSLO imaging was associated with increasing age (P = 0.007) and female sex (P = 0.007), but not with GA total lesion area (P = 0.38). Cohen kappa statistics showed good interobserver agreement for FAF (0.81) and IR (0.82) imaging modes, and moderate agreement was found for BR (0.48), RF (0.48), and CF (0.40). On three-field FAF images RDR were present most frequently superior to the fovea (99%). CONCLUSIONS: RDR represent a common phenotypic hallmark in GA eyes. RDR are readily identified using cSLO imaging technology. These observations may explain the high prevalence determined herein, in contrast to previous reports based on fundus photographs. Incorporation of these novel imaging modalities in future natural history studies may facilitate efforts aimed at defining the role and predictive value of RDR in the progression of AMD. (ClinicalTrials.gov number, NCT00599846.

Multiple forms of contour grouping deficits in schizophrenia: What is the role of spatial frequency?

Schizophrenia patients poorly perceive Kanizsa figures and integrate co-aligned contour elements (Gabors). They also poorly process low spatial frequencies (SFs), which presumably reflects dysfunction along the dorsal pathway. Can contour grouping deficits be explained in terms of the spatial frequency content of the display elements? To address the question, we tested patients and matched controls on three contour grouping paradigms in which the SF composition was modulated. In the Kanizsa task, subjects discriminated quartets of sectored circles (“pac-men”) that either formed or did not form Kanizsa shapes (illusory and fragmented conditions, respectively). In contour integration, subjects identified the screen quadrant thought to contain a closed chain of co-circular Gabors. In collinear facilitation, subjects attempted to detect a central low-contrast element flanked by collinear or orthogonal high-contrast elements, and facilitation corresponded to the amount by which collinear flankers reduced contrast thresholds. We varied SF by modifying the element features in the Kanizsa task and by scaling the entire stimulus display in the remaining tasks (SFs ranging from 4–12 cycles/deg). Irrespective of SF, patients were worse at discriminating illusory, but not fragmented shapes. Contrary to our hypothesis, collinear facilitation and contour integration were abnormal in the clinical group only for the higher SF (>=10 c/deg). Tasks correlated with clinical variables, such as conceptual disorganization, general symptoms, and levels of functioning. In schizophrenia, three forms of contour grouping impairments prominently arise and cannot be attributed to poor low SF processing. Neurobiological and clinical implications are discussed