Effects of response feedback light: behavioral differences between the spontaneously hypertensive rat (SHR) and controls. Artikkel 2

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder found all over the world with a prevalence of around 5% in children and 2.5% in adults. An estimated heritability of 76% has been suggested, which leaves around 20-25% to be caused by environmental factors or a heredity-environmental interaction. The dynamic developmental theory (DDT) is a theory on ADHD based on studies of an animal model called the spontaneously hypertensive rat and suggests that ADHD symptoms are caused by altered reinforcement of novel behavior and deficient extinction of previously learned behavior. Deficit stimulus control or effects of sensory reinforcement may lead to symptoms of ADHD, especially inattention and hyperactivity. In 1992, Sagvolden, Hendley & Knardahl did a study on SHR where they found that by installing a response feedback light above the left lever during extinction in a two-component schedule, the response rate of the SHR increased substantially compared to the other strains. The purpose of the present experiment was to investigate the increased response rate observed in SHR during extinction with the response feedback light, and test whether this activity increase is caused by effects of sensory reinforcement or general discrimination problems. Studies on stimulus control in an animal model may increase the understanding of symptoms and behavior changes observed in children with ADHD.Master i læring i komplekse systeme