Matthew E. Andrzejewski

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BACKGROUND Low doses of psychostimulants, such as methylphenidate (MPH), are widely used in the treatment of attention-deficit/hyperactivity disorder (ADHD). Surprisingly little is known about the neural mechanisms that underlie the behavioral/cognitive actions of these drugs. The prefrontal cortex (PFC) is implicated in ADHD. Moreover, dopamine (DA) and(More)
This study examined the effects of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and the CB1 antagonist SR-141716 on open-field behaviors in male Sprague-Dawley rats. Animals were examined after administration of Delta(9)-THC alone (dose range: 0.3-5.6 mg/kg), SR-141716 alone (dose range: 1-5.6 mg/kg) and the two drugs in combination; injections were given(More)
Intra-nucleus accumbens (Acb) infusion of cholinergic muscarinic antagonist, scopolamine (10 microg/0.5 microl), markedly reduced fat intake elicited by intra-Acb treatment of the mu-opioid receptor agonist, DAMGO, with 30 min and 4h pretreatment intervals. Intra-Acb scopolamine infusions also reduced food intake in food-deprived rats, but not water intake(More)
Previous work has implicated the cholinergic system in modulating feeding behavior; however, its specific function remains unclear. This work aims to characterize potential dissociations between the central cholinergic modulation of the incentive properties of food and food-associated cues, and consummatory behaviors. Three separate experiments demonstrated(More)
Glutamate-coded signaling in corticostriatal circuits has been shown to be important in various forms of learning and memory. In the present study, the authors found that N-methyl-D-aspartate (NMDA) receptor antagonism in the central nucleus of the amygdala (CeA) and the posterior lateral striatum (PLS) impaired instrumental conditioning but had no effect(More)
Opioid transmission and dysregulated prefrontal cortex (PFC) activity have both been implicated in the inhibitory-control deficits associated with addiction and binge-type eating disorders. What remains unknown, however, is whether endogenous opioid transmission within the PFC modulates inhibitory control. Here, we compared intra-PFC opioid manipulations(More)
Low dose amphetamine (AMPH) and methylphenidate (MPH, Ritalin(®)) are the most widely prescribed and most effective pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD). Certain low, clinically relevant doses of MPH improve sustained attention and working memory in normal rats, in contrast to higher doses that impair cognitive ability and(More)
Neural integration of glutamate- and dopamine-coded signals within the nucleus accumbens (NAc) is a fundamental process governing cellular plasticity underlying reward-related learning. Intra-NAc core blockade of NMDA or D1 receptors in rats impairs instrumental learning (lever-pressing for sugar pellets), but it is not known during which phase of learning(More)
Substantial experimental evidence exists suggesting a critical role for dopamine in reinforcer-related processes, such as learning and drug addiction. Dopamine receptors, and in particular D1 receptors, are widely considered as modulators of synaptic plasticity. The amygdala contains both dopamine terminals and dopamine D1 receptors and is intimately(More)
Little is known about how memories of new voluntary motor actions, also known as procedural memory, are formed at the molecular level. Our work examining acquisition of lever-pressing for food in rats has shown that activation of glutamate NMDA receptors, within broadly distributed but interconnected regions (e.g., nucleus accumbens core, prefrontal cortex,(More)