The neonatal rat as a developmental animal model of attention deficit hyperactivity disorder: Effects of frontal lesions on activity and learning

Abstract

We examined a developmental animal model of Attention Deficit Hyperactivity Disorder (ADHD) by evaluating the effects of suppressed frontal cortical functioning on habituation in neonatal rats. Frontal cortical activity was suppressed with brain transections in neonatal rats 3, 6, 9, or 12 days of age. Pups were tested in a habituation‐to‐odor paradigm and behaviors (general activity, headwaving, probing, and rolling) were recorded. Frontal cortical suppression via brain transection resulted in significantly higher activity levels in 3‐day‐old rats, particularly with regard to rolling, suggesting that the frontal cortex is involved in the regulation of this age‐dependent behavior. Frontal transections also increased probing during the odor habituation test in 12‐day‐old pups. Results are consistent with the neuropsychological research regarding frontal cortical functioning and inhibition in children with ADHD, and suggest that neonatal rats with frontal lesions may provide a useful developmental animal model for studying ADHD. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 42: 79–90, 2003.