Effects of atomoxetine, desipramine, d-amphetamine and methylphenidate on impulsivity in juvenile rats, measured in a T-maze procedure.
ABSTRACT Impulsivity is a core symptom of Attention Deficit/Hyperactivity Disorder (ADHD). In the present study, we assessed the effects of two stimulants, methylphenidate and d-amphetamine and of two non stimulant noradrenaline reuptake inhibitors, atomoxetine and desipramine, on the tolerance to delay of reward, taken as an index of impulsivity, in juvenile Wistar rats. Animals were trained in a T-maze to choose between a small-and-immediate reward and a large-but-30s-delayed reward. The effects of drugs were studied on the performance of animals at 30-40 day of age. Methylphenidate (3mg/kg), atomoxetine (1mg/kg), d-amphetamine (1 and 2mg/kg) and desipramine (8 and 16mg/kg) increased the number of choices of the large-but-delayed reward, i.e. decreased impulsivity. Given that these drugs are commonly prescribed in ADHD, these data indicate that the T-maze procedure in juvenile animals may be suitable for testing the therapeutic potential of drugs intended to the treatment of ADHD in children.
Conference Paper: Successive adaptation of neural networks in a multi-agent model[Show abstract] [Hide abstract]
ABSTRACT: This paper examines the adaptability of neural networks to gradual and sudden changes in the environment of a non-cooperative repeated market selection game. Neural networks are used as decision-making systems of agents for iterative game playing. Training data are successively generated from each round of our game by the neural networksNeural Networks, 2002. IJCNN '02. Proceedings of the 2002 International Joint Conference on; 02/2002
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ABSTRACT: Impulsivity is a key symptom of attention-deficit hyperactivity disorder (ADHD). The use of the norepinephrine reuptake inhibitor, atomoxetine, to treat ADHD suggests that the activity of the norepinephrine transporter (NET) may be important in regulating impulsive behavior. Many ADHD patients receive chronic drug treatment during adolescence, a time when frontal brain regions important for impulse control are undergoing extensive development. The current study aimed to determine the effects of chronic atomoxetine treatment during adolescence in rats on two distinct forms of impulsivity in adulthood and whether any behavioral changes were accompanied by alterations in mRNA or protein levels within the frontal cortices. Rats received daily injections of saline or atomoxetine (1 mg/kg) during adolescence (postnatal days 40-54). Two weeks later, animals were trained to perform either the delay-discounting test or the five-choice serial reaction time task (5CSRT). Adolescent atomoxetine treatment caused a stable decrease in selection of small immediate rewards over larger delayed rewards (impulsive choice) in adulthood, but did not affect premature responding (impulsive action) in the 5CSRT. Chronic atomoxetine treatment also altered the ability of acute atomoxetine to modulate aspects of impulsivity, but did not change the response to d-amphetamine. Ex vivo analysis of brain tissue indicated that chronic atomoxetine decreased phosphorylation of CREB and ERK in the orbitofrontal cortex and decreased mRNA for BDNF and cdk5. These data suggest that repeated administration of atomoxetine in adolescence can lead to stable decreases in impulsive choice during adulthood, potentially via modulating development of the orbitofrontal cortex.Psychopharmacology 08/2011; 219(2):285-301. · 4.06 Impact Factor