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Take it or leave it: prefrontal control in recreational cocaine users.


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Authors

Morein-Zamir, S 
Simon Jones, P 
Bullmore, ET 
Robbins, TW 
Ersche, KD 

Abstract

Though stimulant drugs such as cocaine are considered highly addictive, some individuals report recreational use over long periods without developing dependence. Difficulties in response inhibition have been hypothesized to contribute to dependence, but previous studies investigating response inhibition in recreational cocaine users have reported conflicting results. Performance on a stop-signal task was examined in 24 recreational cocaine users and 32 healthy non-drug using control participants matched for age, gender and verbal intelligence during functional magnetic resonance imaging scanning. The two groups were further matched on traumatic childhood histories and the absence of family histories of addiction. Results revealed that recreational cocaine users did not significantly differ from controls on any index of task performance, including response execution and stop-signal reaction time, with the latter averaging 198 ms in both groups. Functional magnetic resonance imaging analyses indicated that, compared with controls, stopping in the recreational users was associated with increased activation in the pre-supplementary motor area but not the right inferior frontal cortex. Thus, findings imply intact response inhibition abilities in recreational cocaine users, though the distinct pattern of accompanying activation suggests increased recruitment of brain areas implicated in response inhibition. This increased recruitment could be attributed to compensatory mechanisms that enable preserved cognitive control in this group, possibly relating to their hypothetical resilience to stimulant drug dependence. Such overactivation, alternatively, may be attributable to prolonged cocaine use leading to neuroplastic adaptations.

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Keywords

Adult, Brain, Case-Control Studies, Central Nervous System Stimulants, Cocaine, Cocaine-Related Disorders, Executive Function, Female, Frontal Lobe, Functional Neuroimaging, Humans, Inhibition, Psychological, Magnetic Resonance Imaging, Male, Motor Cortex, Prefrontal Cortex, Reaction Time, Task Performance and Analysis, Young Adult

Journal Title

Transl Psychiatry

Conference Name

Journal ISSN

2158-3188
2158-3188

Volume Title

5

Publisher

Springer Science and Business Media LLC
Sponsorship
Medical Research Council (G1000183)
Medical Research Council (G0701497)
Medical Research Council (G0001354)
Wellcome Trust (089589/Z/09/Z)
Wellcome Trust (093875/Z/10/Z)
This work was funded by a Medical Research Council (MRC) research grant to KDE, ETB and TWR (G0701497) and was conducted within the Behavioural and Clinical Neuroscience Institute, University of Cambridge, UK, which is supported by a joint award from the MRC and the Wellcome Trust; Both KDE and PSJ were supported by the MRC, SM was supported by a Wellcome Trust grant (089589/Z/09/Z) awarded to TW Robbins.