Addiction Rehab: Dorsolateral Prefrontal and Orbitofrontal Cortex Interactions During Self-Control of Cigarette Craving.
Dorsolateral prefrontal and orbitofrontal cortex interactions during self-control of cigarette craving.
Filed under: Addiction Rehab
Proc Natl Acad Sci U S A. 2013 Jan 28;
Hayashi T, Ko JH, Strafella AP, Dagher A
Drug-related cues induce craving, which may perpetuate drug use or trigger relapse in addicted individuals. Craving is also under the influence of other factors in daily life, such as drug availability and self-control. Neuroimaging studies using drug cue paradigms have shown frontal lobe involvement in this contextual influence on cue reactivity, but have not clarified how and which frontal area accounts for this phenomenon. We explored frontal lobe contributions to cue-induced drug craving under different intertemporal drug availability conditions by combining transcranial magnetic stimulation and functional magnetic resonance imaging in smokers. We hypothesized that the dorsolateral prefrontal cortex (DLPFC) regulates craving during changes in intertemporal availability. Subjective craving was greater when cigarettes were immediately available, and this effect was eliminated by transiently inactivating the DLPFC with transcranial magnetic stimulation. Functional magnetic resonance imaging demonstrated that the signal most proportional to subjective craving was located in the medial orbitofrontal cortex across all contexts, whereas the DLPFC most strongly encoded intertemporal availability information. The craving-related signal in the medial orbitofrontal cortex was attenuated by inactivation of the DLPFC, particularly when cigarettes were immediately available. Inactivation of the DLPFC also reduced craving-related signals in the anterior cingulate and ventral striatum, areas implicated in transforming value signals into action. These findings indicate that DLPFC builds up value signals based on knowledge of drug availability, and support a model wherein aberrant circuitry linking dorsolateral prefrontal and orbitofrontal cortices may underlie addiction.
HubMed – addiction
Epigenetics and Psychostimulant Addiction.
Filed under: Addiction Rehab
Cold Spring Harb Perspect Med. 2013 Jan 28;
Schmidt HD, McGinty JF, West AE, Sadri-Vakili G
Chronic drug exposure alters gene expression in the brain and produces long-term changes in neural networks that underlie compulsive drug taking and seeking. Exactly how drug-induced changes in synaptic plasticity and subsequent gene expression are translated into persistent neuroadaptations remains unclear. Emerging evidence suggests that complex drug-induced neuroadaptations in the brain are mediated by highly synchronized and dynamic patterns of gene regulation. Recently, it has become clear that epigenetic mechanisms contribute to drug-induced structural, synaptic, and behavioral plasticity by regulating expression of gene networks. Here we review how alterations in histone modifications, DNA methylation, and microRNAs regulate gene expression and contribute to psychostimulant addiction with a focus on the epigenetic mechanisms that regulate brain-derived neurotrophic factor (BDNF) expression following chronic cocaine exposure. Identifying epigenetic signatures that define psychostimulant addiction may lead to novel, efficacious treatments for drug craving and relapse.
HubMed – addiction
[Neurocognitive screening in substance addicts: the Montreal Cognitive Assessment].
Filed under: Addiction Rehab
Rev Neurol. 2013 Feb 1; 56(3): 129-36
Rojo-Mota G, Pedrero-Perez EJ, Ruiz-Sanchez de Leon JM, Llanero-Luque M, Puerta-Garcia C
INTRODUCTION. The detection of neurocognitive disorders in addicts would allow subjects with functional impairment to be assigned to cognitive rehabilitation programmes. The Montreal Cognitive Assessment (MoCA) is a screening test that can be a valuable aid with this kind of patient. AIMS. To use the MoCA with a sample of subjects with addictions who are receiving treatment and to compare the results with the criteria proposed for the general population, mild cognitive impairment and early dementias. It also intends to examine the concurrent validity with global execution tests and the relationship with socio-demographic variables and others related to addiction. PATIENTS AND METHODS. The MoCA and the Allen Cognitive Level Screen-5 (ACLS-5) test were administered to a sample of 79 patients with addiction who were beginning treatment in a specific centre. RESULTS. Only 29.1% of the participants presented normal performance in terms of the criteria proposed by the authors. The others achieved scores below the cut-off point, many of them displaying an alarmingly low score, even when compared with criteria for mild cognitive impairment and early dementias. The MoCA showed concurrent validity with the ACLS-5 and correlation with academic level, but not with variables related to addiction. CONCLUSIONS. The MoCA is a test that is quick and simple to administer and correct. It allows the detection of subjects with extremely low cognitive performance that require neuropsychological and occupational interventions for cognitive rehabilitation, which increases treatment compliance and the benefits to be gained from other interventions with important cognitive demands, such as relapse prevention psychotherapy.
HubMed – addiction
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