Young adult stimulant users' increased striatal activation during uncertainty is related to impulsivity

Abstract

Background-Young adults who use stimulants (e.g., cocaine, amphetamines) are at particular risk of transitioning to dependence. Previously, we demonstrated increased risk-taking in young adults who had used stimulants (Leland and Paulus, 2005). Since outcome uncertainty is a critical element of risk, we investigated whether such individuals have different neural responses to uncertainty than their stimulant-naïve peers.

Neuropsychological profiling of impulsivity and compulsivity in cocaine dependent individuals

“…Human neuropsychological and imaging studies have provided indirect support to this model. The notion that increased impulsivity underlies early stages of drug use is consistent with findings showing that recreational psychostimulant users (those who have minimal or intermittent use of these drugs but do not meet criteria for psychostimulant dependence) have elevated scores on trait measures of impulsivity and poor inhibitory control (indexed by go/no-go or stop-signal tasks) associated with functional alterations of striatal function (Colzato et al 2007;Leland et al 2006;Verdejo-García et al 2010). On the other hand, studies conducted in chronic cocainedependent individuals have underscored the presence of robust and durable impairments on indices of flexibility and perseveration (Ersche et al 2008;Verdejo-García et al 2007a;Woicik et al 2011).…”

Milnacipran enhances the control of impulsive action by activating D1-like receptors in the infralimbic cortex

“…Meanwhile, increased dopamine release in the NAc stimulates impulsive behavior (Cole and Robbins 1987;Pattij et al 2006). Administrations of drugs that activate the dopamine system not only in the mPFC but also in the NAc induce rather impaired impulse control in humans (Leland et al 2006) and in animals (van : Milstein et al 2010. However, inhibition of the noradrenaline transporters by atomoxetine induces an increase of dopamine release in the mPFC without affecting dopamine release in the NAc (Bymaster et al 2002) and consequently enhances impulse control (Robinson et al 2008;Tsutsui-Kimura et al 2009).…”

Altered reward expectancy in individuals with recent methamphetamine dependence

“…Stimulant-using individuals often demonstrate dysfunctional decision-making, which may predate the initiation of use (Leland et al, 2006; Leland and Paulus, 2005; Paulus et al, 2008). Individuals with a history of methamphetamine use (METH+) in particular appear more influenced by the immediately preceding choice (Paulus et al, 2002), show a rigid stimulus-response relationship (Paulus et al, 2003), and are less able to adjust decision-making to short-term versus long-term gains (Gonzalez et al, 2007).…”