Executive dysfunction in cocaine addiction: Evidence for discordant frontal, cingulate, and cerebellar activity
ABSTRACT Using a GO-NOGO response inhibition task in which working memory (WM) demands can be varied, we demonstrate that the compromised abilities of cocaine users to exert control over strong prepotent urges are associated with reduced activity in anterior cingulate and right prefrontal cortices, two regions thought to be critical for implementing cognitive control. Furthermore, unlike drug-naive controls, and opposite to the anterior cingulate pattern, cocaine users showed an over-reliance on the left cerebellum, a compensatory pattern previously seen in alcohol addiction. The results indicate that cocaine users find it difficult to inhibit their own actions, particularly when WM demands, which have been shown previously to increase during cue-induced craving for the drug, are increased. The results reveal a neuroanatomical basis for this dysexecutive component to addiction, supporting the suggested importance cognitive functions may play in prolonging abuse or predisposing users toward relapse.
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ABSTRACT: Improved neuroscientific understanding of high-risk behaviors such as alcohol binging, drug use, and unsafe sex will lead to therapeutic advances for high-risk groups. High-risk behavior often occurs in an emotionally-charged context, and behavioral inhibition and emotion regulation play important roles in risk-related decision making. High impulsivity is an important potential contributor to high-risk behavior tendencies. We explored the relationships between high-risk behavior tendencies, impulsivity, and fMRI brain activations in an emotional Go/NoGo task. This task presented emotional distractor pictures (aversive vs. neutral) simultaneously with Go/NoGo stimuli (square vs. circle) that required a button press or withholding of the press, respectively. Participants' risk behavior tendencies were assessed with the Cognitive Appraisal of Risky Events (CARE) scale. The Barratt Impulsivity Scale 11 (BIS) was used to assess participant impulsivity. Individuals with higher CARE risk scores exhibited reduced activation related to response inhibition (NoGo−Go) in right orbital frontal cortex (OFC) and ventromedial prefrontal cortex. These regions did not show a significant relationship with impulsivity scores. Conversely, more impulsive individuals showed reduced emotion-related activity (aversive−neutral distractors) in dorsomedial prefrontal cortex, perigenual anterior cingulate cortex, and right posterior OFC. There were distinct neural correlates of high-risk behavior tendency and impulsivity in terms of brain activity in the emotional Go/NoGo task. This dissociation supports the conception of high-risk behavior tendency as a distinct construct from that of impulsivity. Our results suggest that treatment for high-risk behavior may be more effective with a nuanced approach that does not conflate high impulsivity necessarily with high-risk behavior tendencies.Frontiers in Systems Neuroscience 03/2015; 9. DOI:10.3389/fnsys.2015.00024
Neurociencias y adiciones, Edited by Eduardo Pedrero Pérez, José María Ruiz Sánchez de León, Antonio Verdejo García, Marcos Llanero Luque, Emilio Ambrosio Flores, 01/2011: chapter Factores de vulnerabilidad para desarrollar una adicción: elementos para su prevención: pages 99-110; Sociedad Española de Toxicomanías., ISBN: 978-84-615-0572-2
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ABSTRACT: Paradoxical behaviours characterizing an addiction could be understood as the result of a combination between an attempt to cope with dominant painful feelings (e.g., anxiety with low self-esteem) and sub-optimal decision-making prioritizing short-term over long-term consequences. This article focused on decision-making and emphasized that addicts' decisions are determined by immediate outcomes because of abnormal interactions between key neural and cognitive systems: (1) an automatic, habitual and salient information processing mediated by amygdala-striatum dependent system; (2) an intention self-regulatory system forecasting the future consequences of a choice; (3) a interoceptive signals processing system which generates feeling states and in turn plays a strong influential role in decision-making and impulse control processes related to uncertainty, risk, and reward. As a whole, sub-optimal interactions such as a too strong automatic stimulus-driven actions associated with poor intentional control and a state of stress or craving are thought to result in prioritizing short-term consequences at the detriment of the necessary forecast of delayed consequences.