Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.
"Furthermore, cocaine users exhibit impaired cognitive control and increased impulsivity (Goldstein and Volkow, 2002; Kjome et al., 2010; Lane et al., 2007), as well as decreased sensorimotor performance (Hanlon et al., 2009, 2010), suggesting a broad range of consequences from long-term cocaine exposure. These impairments are accompanied by alterations in the regulation of transmitter systems (Volkow et al., 2006; Martinez et al., 2004; Mash et al., 2002, 2005), reductions in functional activity in the prefrontal cortex (Volkow et al., 1992), decreases in gray matter volume (Hanlon et al., 2011; Matochik et al., 2003; Fein et al., 2002; Lim et al., 2008), and reductions in the integrity of white matter (Franklin et al., 2002; Lim et al., 2002; Ma et al., 2009; Moeller et al., 2005) among many other deficits when compared to healthy controls. Studies, particularly those in animal models, have shown that many of these abnormalities result from repeated exposure to cocaine, and are not merely the result of conditions that pre-date drug use. "
[Show abstract][Hide abstract] ABSTRACT: Cocaine users exhibit a wide range of behavioral impairments accompanied by brain structural, neurochemical and functional abnormalities. Metabolic mapping studies in cocaine users and animal models have shown extensive functional alterations throughout the striatum, limbic system, and cortex. Few studies, however, have evaluated the persistence of these effects following cessation of cocaine availability. The purpose of this study, therefore, was to assess the functional effects of re-exposure to cocaine in nonhuman primates after the discontinuation of cocaine self-administration for 30 or 90 days, using the quantitative autoradiographic 2-[(14)C]deoxyglucose (2DG) method. Rhesus monkeys self-administered cocaine (fixed interval 3-min schedule, 30 infusions per session, 0.3 mg/kg/infusion) for 100 sessions followed by 30 (n=4) or 90 days (n=3) during which experimental sessions were not conducted. Food-reinforced control animals (n=5) underwent identical schedules of reinforcement. Animals were then re-exposed to cocaine or food for one final session and the 2DG method applied immediately after session completion. Compared to controls, re-exposure to cocaine after 30 or 90 day drug-free periods resulted in lower rates of glucose utilization in ventral and dorsal striatum, prefrontal and temporal cortex, limbic system, thalamus, and midbrain. These data demonstrate that vulnerability to the effects of cocaine persists for as long as 90 days after cessation of drug use. While there was some evidence for recovery (fewer brain areas were affected by cocaine re-exposure at 90 days as compared to 30 days), this was not uniform across regions, thus suggesting that recovery occurs at different rates in different brain systems.
Full-text · Article · Jun 2014 · Neuropharmacology
"Neuroimaging studies suggest that decreased dopamine-related activation of reward circuits may account for hypoactivation in the ACC (Volkow et al. 1993). Our finding of decreased ACC activation in former users is consistent with reports in the literature that cocaine abusers show reduced ACC activation 3 to 4 months after withdrawal (Volkow et al. 1992) and neuropsychological deficits up to 6 months of abstinence (Bolla et al. 2000; Di Sclafani et al. 2002; van Gorp et al. 1999). HIV-infected individuals with and without a history of cocaine abuse show decreased dopamine transporters in the dorsal striatum, and this reduction Table 3 Group differences in activation during encoding and recognition: brain region, Brodmann area (BA), SPM coordinates, cluster size (k), and statistical information Brain region BA Coordinates (x, y, z) "
[Show abstract][Hide abstract] ABSTRACT: Crack cocaine use is associated with impaired verbal memory in HIV-infected women more than uninfected women. To understand the neural basis for this impairment, this study examined the effects of crack cocaine use on activation of the prefrontal cortex (PFC) and strategic encoding during a verbal memory task in HIV-infected women. Three groups of HIV-infected women from the Chicago Consortium of the Women's Interagency HIV Study were compared: current users of crack cocaine (n = 10), former users of cocaine (n = 11), and women who had never used cocaine (n = 9). Participants underwent functional magnetic resonance imaging during a verbal memory task and completed a neuropsychological test of verbal memory. On the neuropsychological test, current crack users performed significantly worse than other groups on semantic clustering, a measure of strategic encoding, p < 0.05. During encoding, activation in left anterior cingulate cortex (ACC) was lower in current and former cocaine users compared to never users. During recognition, activation in bilateral PFC, specifically left dorsal medial PFC and bilateral dorsolateral PFC, was lower in current and former users compared to women who had never used cocaine. Lower activation in left dorsolateral PFC was correlated with worse performance on the recognition task, p < 0.05. The verbal learning and memory deficits associated with cocaine use in women with HIV may be partially accounted for by alterations in ACC and PFC function.
Full-text · Article · Apr 2014 · Journal of NeuroVirology
"Increasing evidence has suggested that poor inhibitory control resulting from sub-optimal functioning of prefrontal cortical structures (Volkow & Fowler, 2000; Naqvi & Bechara, 2009; Ersche et al., 2012) that may precede (Volkow & Fowler, 2000; Ersche et al., 2012), or be the result of, chronic exposure to addictive drugs may provide an important mechanism underlying the propensity to lose control over drug intake and to seek cocaine compulsively (Volkow et al., 1992; Grant et al., 1996; Rogers et al., 1999; Hester & Garavan, 2004; Ersche et al., 2005). Individuals addicted to cocaine or other drugs of abuse show decreased grey matter volume in several subregions of the prefrontal cortex (PFC), including the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and insular cortex (IC) (Franklin et al., 2002; Matochik et al., 2003; Ersche et al., 2011, 2012), as well as alterations in the amygdala, albeit with less consistent findings (Makris et al., 2004; Ersche et al., 2012), and white matter changes suggesting disrupted connectivity between cortical and striatal structures (Ersche et al., 2012). "
[Show abstract][Hide abstract] ABSTRACT: Compulsive drug use and a persistent vulnerability to relapse are key features of addiction. Imaging studies have suggested that these features may result from deficits in prefrontal cortical structure and function, and thereby impaired top-down inhibitory control over limbic-striatal mechanisms of drug-seeking behaviour. We tested the hypothesis that selective damage to distinct subregions of the prefrontal cortex, or to the amygdala, after a short history of cocaine taking would: (i) result in compulsive cocaine seeking at a time when it would not usually be displayed; or (ii) facilitate relapse to drug seeking after abstinence. Rats with selective, bilateral excitotoxic lesions of the basolateral amygdala or anterior cingulate, prelimbic, infralimbic, orbitofrontal or anterior insular cortices were trained to self-administer cocaine under a seeking-taking chained schedule. Intermittent mild footshock punishment of the cocaine-seeking response was then introduced. No prefrontal cortical lesion affected the ability of rats to withhold their seeking responses. However, rats with lesions to the basolateral amygdala increased their cocaine-seeking responses under punishment and were impaired in their acquisition of conditioned fear. Following a 7-day abstinence period, rats were re-exposed to the drug-seeking environment for assessment of relapse in the absence of punishment or cocaine. Rats with prelimbic cortex lesions showed decreased seeking responses during relapse, whereas those with anterior insular cortex lesions showed an increase. Combined, these results show that acute impairment of prefrontal cortical function does not result in compulsive cocaine seeking after a short history of self-administering cocaine, but further implicates subregions of the prefrontal cortex in relapse.
Full-text · Article · Jul 2013 · European Journal of Neuroscience