Article

Unbalanced neuronal circuits in addiction

National Institute on Drug Abuse, National Institutes of Health, Bethesda, MD 20892, United States. Electronic address: .
Current opinion in neurobiology (Impact Factor: 6.63). 02/2013; 23(4). DOI: 10.1016/j.conb.2013.01.002
Source: PubMed

ABSTRACT

Through sequential waves of drug-induced neurochemical stimulation, addiction co-opts the brain's neuronal circuits that mediate reward, motivation to behavioral inflexibility and a severe disruption of self-control and compulsive drug intake. Brain imaging technologies have allowed neuroscientists to map out the neural landscape of addiction in the human brain and to understand how drugs modify it.

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    • "According to these researchers, the 'paradox of addiction' could be explained by neurobiological disruptions or cognitive biases in brain regions important to the motivational, reward and inhibitory control processes (Koob, 2013; Volkow et al., 2013). "
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    ABSTRACT: Background: Substance use disorders (SUD) are associated with several neurobiological disruptions, including biases in attention and approach/avoidance behaviour. The aims of this study were to compare the strength of cognitive biases between light and problematic drinkers, to explore the role of IQ on the cognitive biases and to study the psychometric qualities of the measures. Method: Participants (N = 130) were divided into four groups based on IQ and severity of alcohol use-related problems: light (n = 28) and problematic drinkers (n = 25) with (sub)average IQ and light (n = 33) and problematic drinkers (n = 44) with mild to borderline intellectual disability (MBID). All participants performed the visual dot probe task and the approach avoidance task to measure the strength of cognitive biases. Results: In contrast with the hypothesis, no cognitive biases were found in problematic drinkers. Full scale IQ nor level of craving influenced the strength of the cognitive biases in light and problematic drinkers, although IQ did influence task performance (i.e. large intra-individual, trial-to-trial variation in reaction time). The internal consistency of the visual dot probe task was good, whereas the internal consistency of the approach avoidance task was poor. Conclusion: Cognitive biases seem to vary within the group of problematic drinkers as a whole. The psychometric qualities of the measures are problematic, especially in relation to the intra-individual variability in reaction time found in participants with MBID. Until the implications of this variability on the validity of implicit measures and establishing bias scores are more clear, the use of these measures in individuals with MBID calls for scrutiny.
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    • "What's more, its involvement in inhibitory control is regarded as a key role in drug seeking behaviors (Feil et al. 2010). Projections from several PFC regions such as the ACC, OFC and DLPFC to the striatum, passing through the pallidum and thalamus, constitute the prefrontalstriatal circuits, which are related to cognitive inhibitory control and stimulus–response habits (Volkow et al. 2013; Kober et al. 2010). Dysfunction of these circuits may be a possible underlying mechanism of addicted behaviors such as impaired inhibition-control and compulsive use despite the negative outcomes, which have been reported in subjects with IGD (Dong et al. 2010; Young 1998b). "
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    • "These dopamine spikes are thought to become hyper-salient incentive cues that elicit the phenomenon of 'wanting' (Berridge 2007), and dwarf the reward value of other occupational activities. These underpinnings are thought to account for the observed behaviour (participation in the addiction at the expense of engaging in other occupational responsibilities) of people with addictions (Volkow et al 2013). Attempts to abstain from the addictive behaviour are thwarted due to a number of neurobiological changes affecting dopamine transmission and other related neuronal processes (Koob and Le Moal 2005). "
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