ReviewImpulsivity, frontal lobes and risk for addiction
Section snippets
Introduction: executive function and impulsivity
Executive functions in cognitive psychology control abstract thinking, rule acquisition, planning and flexibility in responses including rule shifting, as well as initiating appropriate actions and inhibiting inappropriate actions. Impulsivity has a range of definitions that generally include actions that are poorly conceived, prematurely expressed, unduly risky or inappropriate to the situation that often result in undesirable consequences (Evenden, 1999, de Wit, 2009). At times, impulsivity
Frontal lobes and goal-directed activity
The prefrontal cortex (PFC), including orbitofrontal gyri and the anterior cingulated cortex, are important for executive functions. The PFC is defined as the projection region of the medial dorsal thalamus that includes the dorsal lateral prefrontal cortex (dlPFC), anterior cingulated cortex (ACC), and orbital frontal cortex (OFC). When properly functioning, the frontal lobes equip individuals with the capacity to use past experience and knowledge to make sense of current behavior and to guide
Frontal lobes and addiction
Addiction is simply defined as engaging in the continued use of substances or activities in the face of negative consequences. Addiction appears to result from a combination of precipitating environmental factors and underlying biological risk factors, similar to other neurobehavioral disorders, like schizophrenia or depression. The biological mechanisms of addiction have been explored in great detail, uncovering much about the neurobiology of drug self-administration and effects of chronic
Alcoholic neurodegeneration and executive dysfunction
Heavy drinking and high blood alcohol levels induce neurodegeneration and frontal-cortical dysfunction. As mentioned above, frontal-cortical dysfunction and impulsivity likely contribute to the consumption of dangerous amounts of alcohol despite the knowledge that problems occur as a result of drinking, the key characteristic of alcohol use disorders. Alcohol use disorder is in part due to a heavy drinking environment. High alcohol consumption causes neurodegeneration that contributes to loss
Genetic regulation of impulsiveness and risk for addiction
Polymorphisms in several genes in the dopaminergic system, which targets the frontal and limbic brain structures that regulate impulsive behavior, have been identified as likely contributors to impulsivity (Kreek et al., 2005). For example, recent results indicate that genetic variation at the Val158Met polymorphism of the catechol-O-methyltransferase (COMT) gene influences decision-making behavior and underlying activity in brain activity associated with impulsive choice (Boettiger et al., 2007
Adolescent brain development represents a critical risk period for addiction
Adolescence is an important period of development during the transition from childhood to adulthood. Adolescence is best defined by characteristic behaviors such as high social interaction, high levels of risk-taking, high exploration, impulsivity, novelty and sensation seeking, high activity and play behaviors. These are shared across species from humans (12 to 20–25 years of age), to rats (post-natal days 28 to 42) and many other species (Spear, 2000). The characteristic behaviors of
The frontal cortex and stages of change in recovery from addiction
Recovery from addiction involves a significant change in behavior. The factors that regulate the persistence of dependence and motivation to control addictive behavior reflect aspects of the decisional balance between reflective and impulsive systems. Psychological changes that occur during recovery from addiction involve motivation and have been modeled as “Stages of Change” as an aid to therapists with a diversity of clients in various phases of recovery (Fig. 8) (DiClemente, 2007). Addicted
Summary
The fundamental problem in addiction is the destructive nature of the substance abuse and the inability to stop. The frontal regions of the brain control behaviors including planning and organization, motivation for goal-directed activity, weighing consequences of future actions and impulse inhibition, known collectively as executive functions. The PFC projects to ACC and OFC, with all 3 projecting to the VS, a dopamine rich area important for expression of behaviors. Frontal-cortical damage
Acknowledgements
The authors wish to thank the National Institute of Alcohol Abuse and Alcoholism, the UNC-Bowles Center for Alcohol Studies and the UNC-Biomedical Research Imaging Center for support.
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