Successive negative contrast effects in a risk-sensitive foraging procedure.

Although a wealth of studies have evidenced successive negative contrast effects in instrumental or operant procedures, relatively few studies have determined if and how a sudden downshift in reward quality alters foraging behaviour. In light of research by ecologists and psychologists in the area of risk-sensitive foraging, this area would serve as an adequate framework to examine the effects of a sudden downshift in reward quality on foraging behaviour. Therefore, the purpose of the current experiment was to explore if and how a sudden downshift in reward quality altered risk-sensitive foraging in rats. Subjects chose between a variable and fixed option that returned the same mean amount of sugar pellets, but one group of subjects (i.e., contrast group) were downshifted from 100% to 20% sugar pellets, whereas an unshifted control group received 20% sugar pellets throughout the study. Consistent with past risk-sensitive foraging research where reward quality was manipulated, subjects in the contrast group displayed significantly more risk-prone choices when reward quality was decreased from 100% to 20% sugar. However, the change in choice was inconsistent with contrast effects observed in prior contrast experiments. In addition to choice behaviour, other behavioural measures (e.g., rejected food, latency to choice) were significantly different between the unshifted control and contrast group and across conditions in the contrast group (e.g., latency to choice and rejected food significantly increased when reward quality changed from 100% to 20% sugar). These findings revealed a contrast effect and were similar to past contrast studies where reward quality was downshifted. Thus, when foragers experience a sudden downshift in reward quality, they may display significant behavioural changes and, in turn, display a bias for patches that yield a greater reward quality despite potentially lower payoffs. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Pediatric to Adult Transitions of Ketogenic Dietary Therapy for Epilepsy.

Ketogenic therapy is now an accepted treatment for pediatric and adult patients with medically refractory epilepsy.1-3 However, young adults treated with a ketogenic diet face unique challenges when transitioning to adult neurology providers.4 The variable acceptance of dietary therapy, paucity of nutritionists and adult neurology providers educated in dietary therapy, and lack of insurance coverage for dietary education may interfere with transition to adult care. In addition, patients in this life stage may just begin to independently seek medical care, cook meals, and manage medications, making strict dietary limitations difficult.4 In this worldwide study, we surveyed 191 pediatric and adult neurology providers who prescribe ketogenic dietary therapy for epilepsy. Our response rate was 39% with a total of 74 valid surveys received. Our goal was to identify perceived barriers that inhibit effective transition and successful continuation of dietary therapy during transition to adult care. We found that dietary therapy is a more accepted treatment of intractable epilepsy in children (84%) than adults (17%) in all geographic areas. Although half of pediatric neurology providers (50%) transition their young adult patients on dietary therapy to adult providers, only 23% have a documented transition plan or a formal transition protocol. Most (87%) pediatric providers who prescribe the ketogenic diet feel the lack of sufficient adult providers who prescribe dietary therapy as a barrier to transitioning adolescent and young adult patients.