Unravelling Impulsivity by Optogentically stimulating Noradrenergic and Dopaminergic Neuronal circuitry

Abstract

Impulsivity is a multifaceted phenomenon linked to drug addiction, pathological gambling, and attention deficit hyperactivity disorder (ADHD) and personality disorders such as the manic phase of bipolar disorder. Dopaminergic (DA) and noradrenergic (NE) reuptake inhibitors are used to treat the impulsive aspect of these disorders and it is known that these drugs act upon frontostriatal regions to do so. Nonetheless, it is still not understood how endogenous DA and NE neuronal activity modulates impulsivity within frontostriatal circuitry nor is the method of action of the current drugs available very well described. For this reason, I propose to investigate the role of DA and NE neuronal activity in frontostriatal circuits. To accomplish this, I will use optogenetics to stimulate DA and NE afferents into the nucleus accumbens and into the orbitofrontal cortex in rats during the assessment of impulsive behaviours. Impulsive traits will then be measured using the well-established, translational behavioural paradigms the 5-Choice-Serial-Reaction-Time-Task (5-CSRTT) and the Delayed Reward Task (DRT). These tasks will each measure impulsive action and impulsive choice respectively.