Visual Exploration and Object Recognition by Lattice Deformation

Mechanisms of explicit object recognition are often difficult to investigate and require stimuli with controlled features whose expression can be manipulated in a precise quantitative fashion. Here, we developed a novel method (called “Dots”), for generating visual stimuli, which is based on the progressive deformation of a regular lattice of dots, driven by local contour information from images of objects. By applying progressively larger deformation to the lattice, the latter conveys progressively more information about the target object. Stimuli generated with the presented method enable a precise control of object-related information content while preserving low-level image statistics, globally, and affecting them only little, locally. We show that such stimuli are useful for investigating object recognition under a naturalistic setting – free visual exploration – enabling a clear dissociation between object detection and explicit recognition. Using the introduced stimuli, we show that top-down modulation induced by previous exposure to target objects can greatly influence perceptual decisions, lowering perceptual thresholds not only for object recognition but also for object detection (visual hysteresis). Visual hysteresis is target-specific, its expression and magnitude depending on the identity of individual objects. Relying on the particular features of dot stimuli and on eye-tracking measurements, we further demonstrate that top-down processes guide visual exploration, controlling how visual information is integrated by successive fixations. Prior knowledge about objects can guide saccades/fixations to sample locations that are supposed to be highly informative, even when the actual information is missing from those locations in the stimulus. The duration of individual fixations is modulated by the novelty and difficulty of the stimulus, likely reflecting cognitive demand

Mid‑term impact of home‑based follow‑up care on health‑related quality of life of hypertensive patients at a teaching hospital in Ilorin, Nigeria

Background: Health‑related quality of life (HRQoL) is an important clinicaloutcome assessment in hypertension management, given the lifelong (chronicity) nature and the need for daily self‑management for hypertensive patents. Of some of the studies that implemented  home‑based interventions on hypertension globally, the HRQoL is rarely used as a primary outcome measure. This study developed, implemented, and assessed the impact of home‑based follow‑up care (HBFC) on HRQoL of hypertensive patients attending outpatients’ clinics in Ilorin, Nigeria. Materials and Methods: A total of 149 and 150 patients were randomized to intervention and usual care (control) groups, respectively. A 12‑month task‑shifting (nurse‑driven) HBFC intervention was administered to intervention group. The mid‑term impact of intervention on HRQoL was assessed after 6 months intervention. Data were analyzed with intention‑to‑treat principle. Treatment effects were measured with the t‑tests, analysis of covariance, and multivariate analysis of covariance analysis. Significant levels were set at P < 0.05 and 95% confidence interval. Results: The between‑group treatment effect was not statistically significant (P > 0.05), whereas the within‑group treatment effects were statistically significant for both the intervention and control arms (P < 0.05) at 6 months. After controlling for age and baseline HRQoL, the intervention group had an improved physical component of HRQoL than the control group. The intervention group also had statistically significant improvement in blood pressure control, medication adherence, and symptom counts (P < 0.05).Conclusion: The HBFC intervention for hypertensive patients impacted positively on physical component of HRQoL after controlling for baseline HRQoL and age of the patients at 6 months post‑intervention.Keywords: Home-based care, hypertension, Ilorin, quality of lif