Neural circuitry and mechanisms of waiting impulsivity: relevance to addiction

Abstract

Impatience—the failure to wait or tolerate delayed rewards (e.g. food, drug and monetary incentives)—is a common behavioural tendency in humans. However, when rigidly and rapidly expressed with limited regard for future, often negative consequences, impatient or impulsive actions underlie and confer susceptibility for such diverse brain disorders as drug addiction, attention-deficit hyperactivity disorder (ADHD) and major depressive disorder. Consequently, ‘waiting’ impulsivity has emerged as a candidate endophenotype to inform translational research on underlying neurobiological mechanisms and biomarker discovery for many of the so-called impulse-control disorders. Indeed, as reviewed in this article, this research enterprise has revealed a number of unexpected targets and mechanisms for intervention. However, in the context of drug addiction, impulsive decisions that maximize short-term gains (e.g. acute drug consumption) over longer-term punishment (e.g. unemployment, homelessness, personal harm) defines one aspect of impulsivity, which may or may not be related to rapid, unrestrained actions over shorter timescales. We discuss the relevance of this distinction in impulsivity subtypes for drug addiction with reference to translational research in humans and other animals. This article is part of the theme issue ‘Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications’.

Network failures: When incentives trigger impulsive responses

“…SDI demonstrated similar activations but most robustly to drug‐related cues, where they further showed increased activation in brain areas that encode motivation and emotional salience (e.g., amygdala, OFC). Greater activation to drug incentives in these regions was accompanied by elevated premature responding in the active users, suggesting that incentive salience was driving this behavior, consistent with studies in experimental animals and in other addiction‐related clinical populations (Dalley & Ersche, ; Voon, ).…”

Review of the Neural Processes of Working Memory Training: Controlling the Impulse to Throw the Baby Out With the Bathwater

“…Similarly, in a study of chronic methamphetamine users currently abstinent and engaging in cognitive-behavioral therapy, Brooks and colleagues demonstrated that 4 weeks (20 half-hour sessions) of 0-3-back WMT led to increased bilateral basal ganglia volume (incorporating the striatum) in line with improved self-reported impulse control and self-regulation ( 33 ). In line with Dahlin and colleagues’ hypotheses ( 43 ) as well as others ( 34 , 49 ) increased basal ganglia volume might indicate that WMT forges neuroplasticity changes, enabling more efficient updating capabilities, which support new cognitive strategies for better cognitive control of impulsivity. In line with the importance of striatal structural and functional changes after WMT, Nemmi and colleagues have recently tested the extent to which dopamine-related genes (e.g., COMT and DAT-1), striatal activation and morphology have been associated with increased working memory capacity in different ages of adolescents ( 93 ).…”

“…The first aim of this review has been met, to demonstrate that brain imaging studies of WMT report significant neural effects often independently of behavioral changes in frontoparietal and frontostriatal circuitry. This review has also met its second aim, to demonstrate that there is a paucity of far-transfer measures of impulse control in neuroimaging studies of WMT, despite a wealth of evidence emphasizing that frontoparietal and striatal circuits not only contribute to changes in working memory function across the lifespan but are also associated with the cognitive control of impulsivity ( 34 , 91 ). As such, studies examining the neural effects of WMT associated with impulse control could be a fruitful research avenue to pursue for those aiming to improve neural processes in people with addictive disorders, which often demonstrate comorbid impulse control deficits ( 91 ).…”

“…Thus, it appears that working memory function is predominantly a “top-down” function associated with prefrontal cortex activation, whereas impulsivity is predominantly a “bottom-up” function associated with striatal activation. Nevertheless, despite the dissociation between these two functions, it has well been established that efficient working memory processing is associated with effective frontostriatal activity and reduced impulsivity ( 32 – 34 ).…”

Cocaine-Induced Impulsivity is Differentially Expressed in Male and Female Mice Exposed to Maternal Separation and is Associated with Alterations in AMPA Receptors Subunits

“…Impulsivity is a major personality and temperament dimension consisting of maladaptive 75 behaviour and characterized by poorly conceived, prematurely expressed, unduly risky, or 76 inappropriate actions often resulting in undesirable consequences (Granö et al 2007;Dent 77 and Isles 2014; Dalley and Ersche 2019). Therefore, this personality trait can increase 78 predisposition to suffer drug addiction (Nicholls et al 2014 Depression is the most common psychological disorder affecting more than 264 million 82 people worldwide (James et al 2018).…”