Addiction Rehab: Task Difficulty Modulates the Impact of Emotional Stimuli on Neural Response in Cognitive-Control Regions.

Task difficulty modulates the impact of emotional stimuli on neural response in cognitive-control regions.

Filed under: Addiction Rehab

Front Psychol. 2012; 3: 345
Jasinska AJ, Yasuda M, Rhodes RE, Wang C, Polk TA

Both heightened reactivity to emotional stimuli and impaired cognitive control are key aspects of depression, anxiety, and addiction. But the impact of emotion on cognitive-control processes, and the factors that modulate this impact, are still not well understood. We examined the effects of threat and reward distracters on the neural correlates of cognitive control using functional MRI (fMRI) and the Multi-Source Interference Task (MSIT). Behaviorally, subjects were slower and less accurate on the more demanding incongruent trials compared to the easier congruent trials. In addition, both threat and reward distracters significantly impaired the speed of responding on incongruent trials relative to the no-distracter condition. At the neural level, we used the incongruent – congruent contrast to functionally define four cognitive-control regions of interest (ROIs): anterior cingulate cortex (ACC), left and right inferior frontal gyrus (IFG)/insula, and right dorsolateral prefrontal cortex (DLPFC). A repeated-measures analysis of variance on the extracted contrast values in these ROIs indicated a significant interaction of stimulus salience and task difficulty on the neural response in cognitive-control regions. Specifically, threat distracters significantly decreased the response in cognitive-control regions on incongruent trials, whereas they significantly increased that response on congruent trials, relative to the no-distracter condition. Exploratory analyses of the amygdala response showed a similar interaction of stimulus salience and task difficulty: threat distracters significantly decreased the amygdala response only on incongruent trials. Overall, our results suggest that the impact of emotional distracters on the neural response in cognitive-control regions as well as in the amygdala is modulated by task difficulty, and add to our understanding of the factors that determine whether emotion enhances or impairs cognition.
HubMed – addiction


Cingulate biochemistry in heroin users on substitution pharmacotherapy.

Filed under: Addiction Rehab

Aust N Z J Psychiatry. 2012 Oct 11;
Verdejo-García A, Lubman DI, Roffel K, Vilar-López R, Bora E, Mackenzie T, Yücel M

Objective:High doses of opiate substitution pharmacotherapy are associated with greater treatment retention and lower illicit drug consumption, although the neurobiological bases of these benefits are poorly understood. Dysfunction of the anterior cingulate cortex (ACC) is associated with greater addiction severity and mood dysregulation in opiate users, such that the beneficial effects of substitution pharmacotherapy may relate to normalisation of ACC function. This study aimed to investigate the differential impact of methadone compared with buprenorphine on dorsal ACC biochemistry. A secondary aim was to explore the differential effects of methadone and buprenorphine on dorsal ACC biochemistry in relation to depressive symptoms.Methods:Twenty-four heroin-dependent individuals stabilised on methadone (n=10) or buprenorphine (n=14) and 24 healthy controls were scanned using proton Magnetic Resonance Spectroscopy and compared for metabolite concentrations of N-acetylaspartate, glutamate/glutamine, and myo-inositol.Results:(1) Methadone was associated with normalisation of dorsal ACC biochemistry (increased N-acetylaspartate and glutamate/glutamine levels, and decreased myo-inositol levels) in a dose-dependent manner; (2) buprenorphine-treated individuals had higher myo-inositol and glutamate/glutamine levels than methadone-treated patients in the right dorsal ACC; and (3) myo-inositol levels were positively correlated with depressive symptoms in participants stabilised on buprenorphine.Conclusions:These findings point to a beneficial role of high-dose methadone on dorsal ACC biochemistry, and suggest a link between elevated myo-inositol levels and depressive symptoms in the context of buprenorphine treatment.
HubMed – addiction


Cognitive Performance of Individuals With Schizophrenia Across Seven Decades: A Study Using the MATRICS Consensus Cognitive Battery.

Filed under: Addiction Rehab

Am J Geriatr Psychiatry. 2012 Oct 10;
Rajji TK, Voineskos AN, Butters MA, Miranda D, Arenovich T, Menon M, Ismail Z, Kern RS, Mulsant BH

OBJECTIVES:: The objectives of this study were to determine the effect of aging, schizophrenia, and their interaction on cognitive function. DESIGN:: Cross-sectional controlled study. SETTING:: Community living. PARTICIPANTS:: A total of 235 subjects with schizophrenia age 19-79 and 333 comparison subjects age 20-81. MEASUREMENTS:: The Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB). RESULTS:: Older age was associated with poorer performance on 9 of 10 MCCB tests in both subjects with schizophrenia and comparison subjects. Subjects with schizophrenia were impaired relative to comparison subjects on each of the 10 tests. However, there was no interaction between aging and schizophrenia on any test. Essentially the same results were observed when analyzing performance on the seven MCCB cognitive domains and MCCB global composite score. CONCLUSIONS:: Consistent with other reports, schizophrenia appears to be a disorder marked by generalized cognitive dysfunction. However, the rate of cognitive decline appears to be similar to that observed in healthy comparison subjects. They do not experience acceleration in cognitive aging, which supports the hypothesis that schizophrenia is a syndrome of premature aging. Longitudinal studies including very old patients are needed to confirm and extend these findings.
HubMed – addiction



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