Ronald L Cowan

..This paper reviews existing findings in the context of a cortical model and suggests directions for future research...

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..Additional research is needed to clarify the origin and significance of the current findings...

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..These findings are not supportive of MDMA-induced alterations in NAA or MI levels in this small sample of moderate MDMA users. Limitations to this study suggest caution in the interpretation of these results...

..These findings suggest that cannabis use may contribute to altered neuronal integrity in Ecstasy polydrug users in a brain region associated with verbal memory processing...

..Path analysis confirmed that the impact of decreased midbrain D2/D3 autoreceptor availability on trait impulsivity is mediated in part through its effect on stimulated striatal DA release...

..These findings highlight the role of DA signaling in striatal, prefrontal, and insular regions as key neurochemical mechanisms underlying individual differences in cost/benefit decision-making...

..The authors sought to determine whether individual differences in normal variation in schizotypal traits are correlated with dopamine transmission in the striatum and in extrastriatal brain regions...

..This conclusion has significant implications for neuropsychiatric models that posit global or regionally specific relationships between dopaminergic tone and behavior...

..Whether MDMA produces chronic reductions in serotonin signaling in humans remains controversial...

..In individuals with an inhibited temperament, this sustained response may be related to the wariness of social situations that persists beyond initial exposure...

..Studies have correlated long-term MDMA use with altered brain activation in regions that play a role in verbal memory...

..When considered in the context of previous results, cortical hyper-excitability may be a biomarker for MDMA-induced serotonin neurotoxicity...

..These findings suggest that neurochemical and neurophysiological hyper-reactivity of the dopaminergic reward system may comprise a neural substrate for impulsive-antisocial behavior and substance abuse in psychopathy...

..2009). Blood oxygenation level dependent (BOLD) data from that study were reanalyzed for intraregional coherence and for inter-regional temporal correlations between time series, as functional connectivity...

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..We speculate that the lower midbrain (auto)receptor availability seen in high novelty seekers leads to accentuated dopaminergic responses to novelty and other conditions that induce dopamine release...

..Cannabis dependence is a significant public health problem. Because there are no approved medications for this condition, treatment must rely on behavioral approaches empirically complemented by such lifestyle change as exercise...

..Enhanced amygdala sensitivity coupled with weak inhibitory control from the dACC may form a neural circuit mediating behaviors characteristic of inhibited temperament and risk for anxiety disorders...

..05). This preliminarily supports using fMRI time-series features to assess pontine raphé function. Whether, and how, high frequency activity oscillations interfere with low frequency signaling requires further study...

..Further studies examining behavioral correlates and the specific neurophysiological basis of the observed findings are warranted...

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..We propose that this failure to habituate reflects a social learning deficit in individuals with an inhibited temperament and provides a possible mechanism for increased risk for social anxiety...

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..Many children with heavy exposure to alcohol in utero display characteristic alterations in brain size and structure. However, the long-term effects of low-to-moderate alcohol exposure on these outcomes are unknown...

..Clinical studies comparing dopamine receptor availability between clinical and control groups may benefit by accounting for potential differences in cerebral morphology that exist even after spatial normalization...

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..These findings partially overlap with previous structural evidence for reduced grey matter in MDMA users and may, in part, explain the consistent verbal memory impairments observed in other studies of MDMA users...

..Eventually, we believe that a better understanding of the brain structures that allow us to get high, and become addicted, will lead to improved awareness and treatment for substance abuse. ..

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..Because the rate of depression is greater in females than males, and because regulation of the 5-HT2A receptor is influenced by estrogen, we have chosen to study the effects of having SS or L-A L-A genotype in female subjects. ..

..Exploratory analyses will examine for potential interactions of 5-HT2A receptor and 5-HT transporter genotype with the degree of MDMA exposure and outcome measures of 5-HT2A levels and brain volume. ..