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ABSTRACT: BACKGROUND: Few studies have been previously published about the resting state brain activity in young chronic smokers, although many previous fMRI studies have shown that the task-related activity pattern is altered in chronic smokers. METHODS: In the present study, forty-five healthy smokers (age: 27.9 [PLUS-MINUS SIGN] 5.6 year) and forty-four healthy non-smoking control subjects (age: 26.3 [PLUS-MINUS SIGN] 5.8 year) have been imaged with functional magnetic resonance imaging (fMRI) and analyzed with the regional homogeneity (ReHo) approach. RESULTS: Compared with healthy controls, decreased ReHo was found in smokers in the right inferior frontal cortex and increased ReHo was found in the left superior parietal lobe (P < 0.01, 35 Voxels,Alphasim corrected). CONCLUSIONS: Our data suggested that, during resting state, neural function is less synchronized in the right inferior frontal cortex and more synchronized in the left superior parietal lobe in chronic smokers compared to non-smokers. The decreased synchronization in the right inferior frontal cortex may reflect lacking of control over reward-related behavior, and the increased synchronization may reflect smoking urges.
Behavioral and Brain Functions 08/2012; 8(1):44. · 2.13 Impact Factor
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ABSTRACT: BACKGROUND: Previous neuroimaging studies have documented changes in the brain of heroin addicts. However, few researches have detailed whether such changes can be amended after short-term abstinence. METHODS: We used magnetic resonance imaging (MRI) to investigate gray matter volume in 20 heroin-dependent patients at 3 days and at 1 month after heroin abstinence; 20 normal subjects were also included as controls. RESULTS: Decreased gray matter density in frontal cortex, cingulate and the occipital regions were found in heroin users after three days of abstinence. In contrast, after 1-month abstinence, no significant difference was found in superior frontal gyrus between heroin addicts and controls, but changes in other brain regions, including right middle frontal gyrus, left cingulate gyrus and left inferior occipital gyrus, still remained. CONCLUSION: Our findings illustrate that abnormal gray matter in some brain regions of heroin addicts can return to normal after one-month abstinence.
Drug and alcohol dependence 06/2012; · 3.60 Impact Factor
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ABSTRACT: Ketamine is a non-competitive anatognist of the N-methyl-D-aspartate (NMDA) receptor commonly used as an anesthetic and analgesic. In sub-anesthetic doses, it can induce temporary psychotic symptoms and has served as a pharmacological model for schizophrenia. While its acute effects on brain and behavior have been studied, the effects of long-term exposure to ketamine on brain activity have been largely unexplored. In this study, we aimed to examine such effects on spontaneous brain dynamics measure using resting-state functional magnetic resonance imaging (fMRI). Forty-one patients with ketamine dependence and forty-four healthy control subjects were imaged with BOLD fMRI using a 3.0-Tesla Siemens scanner at the Magnetic Resonance Center of Hunan Provincial People's Hospital, analyzed with the regional homogeneity (ReHo) method. Compared with healthy controls, decreased ReHo was found in ketamine users in the right anterior cingulate cortex and increased ReHo was found in left precentral frontal gyrus (p<0.05, cluster-level corrected). We also observed negative correlations between increased ReHo in precentral frontal gyrus and estimated total lifetime ketamine consumption and ketamine craving levels. To our knowledge, this is the first study the long-term effects of ketamine exposure on brain functional activity. Our findings indicate that ketamine dependence is associated with alterations in the functional connectivity of medial and lateral prefrontal cortices.
Neuroscience Letters 06/2012; 522(1):36-40. · 2.11 Impact Factor
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ABSTRACT: To compare HCV and HIV infection among heroin addicts in MMT and not in MMT in two large cities in central China.
A total of 541 heroin addicts were recruited from MMT clinics and voluntary detoxification centers in Changsha and Wuhan, China. Structured questionnaires collected data on their socio-demographics, clinical status, risk behaviors, and their knowledge of HIV. Their HIV serostatus and Hepatitis C virus (HCV) serostatus were determined by testing antibodies in blood serum.
We observed a higher prevalence of HCV infection among MMT heroin addicts (82.3%) than that in the non-MMT group (50.6%). However, our findings indicated that the heroin addicts in MMT had less drug or sexual HIV/HCV risk behaviors and more knowledge about HIV than non-MMT addicts. The heroin addicts in MMT had a significantly higher percentage of individuals who always used condoms (44.9%) compared with patients in the non-MMT group (14.6%, p = 0.039), and they had more knowledge about HIV than non-MMT individuals (p<.001). The percentage of HIV-positive addicts in the MMT group (0.7%) and non-MMT group (0.8%) were almost same.
Our study indicated that the rate of HCV infection among heroin addicts among MMT or non-MMT settings in central China is very high. The non-MMT heroin addicts have higher risk of becoming infected with HCV in the future, while at present they have lower rates of HCV infection than MMT heroin addicts. Although rates of HIV infection among MMT and non-MMT heroin addicts are low now, they are all at great risk of becoming infected with HIV in the future, especially for non-MMT heroin addicts. We should use the MMT sites as a platform to improve the control of HCV and HIV infection in heroin addicts.
PLoS ONE 01/2012; 7(9):e45632. · 4.09 Impact Factor
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ABSTRACT: To explore the attitudes of medical students toward psychiatry.
A total of 254 fourth-year medical students were investigated with a 29-item questionnaire.
Although in general, medical school students showed a positive attitude towards psychiatry, opinions about certain aspects like the reputation of psychiatry and the attitude toward psychiatric therapy were not positive.
There are still some misunderstandings for psychiatry among medical school students, some of which are based on false beliefs that should be actively targeted for remediation.
Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences 09/2011; 36(9):903-7.
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ABSTRACT: To examine white matter integrity in heroin-dependent patients and matched normal controls with diffusion tensor imaging (DTI).
The fractional anisotropy was compared between 15 heroin-dependent patients and 15 controls.
We found the fractional anisotropy was significantly decreased in specific brain regions of the heroin-dependent patients (P<0.001 uncorrected), including the frontal gyrus, the parietal lobule, the insula, and the corpus callosum.
The presence of microstructural abnormality is found in the white matter of several brain regions of heroin-dependent patients.
Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences 08/2011; 36(8):728-32.
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ABSTRACT: To explore what brain regions are modulated by heroin addiction and withdrawal.
We used functional magnetic resonance imaging to investigate the brain function in 15 heroin-dependent patients 3 days (acute) and 1 month (protracted) after heroin abstinence. Sixteen normal controls were included.
The blood oxygen level-dependent signal in the orbitofrontal cortex of the brain of heroin-dependent patients was significantly elevated 3 days after the withdrawal. Hyperfunction of the orbitofrontal cortex declined 1 month after the withdrawal.
Heroin-dependent subjects at both 3 days and 1 month abstinence have persistent abnormalities in the brain function. Although some tangible beneficial effects are noted following 1 month of detoxification, possible permanent damage to the brain caused by heroin use is suggested.
Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences 08/2011; 36(8):733-8.
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ABSTRACT: Previous neuroimaging studies have documented the structural damage in heroin addicts. However, little research has detailed the white matter microstructural changes in the human brain as a result of chronic heroin use and importantly, whether such changes can be recovered after short-term abstinence. Decreased fractional anisotropy values in frontal cortex were found in heroin users after 3 days of abstinence in comparison with controls. However, no significant difference was found between these heroin addicts and controls after 1-month abstinence. These results might better our understanding of the biological basis of drug addiction and provide insight into addiction treatment.
Addiction Biology 07/2011; · 4.83 Impact Factor
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Yanhui Liao,
Jinsong Tang,
Qijian Deng,
Yongwen Deng,
Tao Luo, Xuyi Wang,
Hongxian Chen,
Tieqiao Liu,
Xiaogang Chen,
Arthur L Brody,
Wei Hao
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ABSTRACT: Cigarette smoking continues to be the leading cause of preventable morbidity and mortality in China and other countries. Previous studies have demonstrated gray matter loss in chronic smokers. However, only a few studies assessed the changes of white matter integrity in this group. Based on those previous reports of alterations in white matter integrity in smokers, the aim of this study was to examine the alteration of white matter integrity in a large, well-matched sample of chronic smokers and non-smokers.
Using in vivo diffusion tensor imaging (DTI) to measure the differences of whole-brain white matter integrity between 44 chronic smoking subjects (mean age, 28.0±5.6 years) and 44 healthy age- and sex-matched comparison non-smoking volunteers (mean age, 26.3±5.8 years). DTI was performed on a 3-Tesla Siemens scanner (Allegra; Siemens Medical System). The data revealed that smokers had higher fractional anisotropy (FA) than healthy non-smokers in almost symmetrically bilateral fronto-parietal tracts consisting of a major white matter pathway, the superior longitudinal fasciculus (SLF).
We found the almost symmetrically bilateral fronto-parietal whiter matter changes in a relatively large sample of chronic smokers. These findings support the hypothesis that chronic cigarette smoking involves alterations of bilateral fronto-parietal connectivity.
PLoS ONE 01/2011; 6(11):e26460. · 4.09 Impact Factor
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ABSTRACT: Dopamine partial agonists have been suggested to be potential therapeutic candidates for pharmacological intervention in drug addiction. These drugs bind to dopamine receptors with high affinity and low intrinsic activity and are hypothesized to behave as functional antagonists in conditions of high dopaminergic tone. The aim of the present study was to characterize the effects of terguride, a partial dopamine agonist at the dopamine D(2) receptor, on intravenous heroin self-administration on fixed- and progressive-ratio schedules of reinforcement. The effects of terguride on oral sweet solution (4% sucrose) self-administration on a fixed-ratio schedule were also tested. Terguride dose-dependently decreased heroin self-administration on the fixed-ratio schedule and decreased the maximum number of responses for heroin self-administration on a progressive-ratio schedule. In contrast, terguride did not significantly affect oral sucrose self-administration. These data suggest that terguride may represent a novel pharmacological strategy for the treatment of opiate addiction.
Pharmacology Biochemistry and Behavior 12/2010; 97(2):222-6. · 2.53 Impact Factor
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ABSTRACT: Use of ketamine as a recreational drug is spreading rapidly among young people all over the world. Epidemiological studies have linked chronic ketamine use with a number of problems, including cognitive impairments, bladder dysfunction, and ketamine-related death. However, little is known about the long-term effects of ketamine use on brain structure and function.
We used voxel based morphometry in conjunction with statistical parametric mapping on the structural magnetic resonance images of ketamine-dependent (n = 41) and drug-naive control individuals (n = 44) to assess differences in gray matter volume between the two groups.
We observed significant decreases in gray matter volume in bilateral frontal cortex (left superior frontal gyrus and right middle frontal gyrus) of ketamine users in comparison with control subjects (p < .05 corrected for multiple comparisons at cluster-level). Duration of ketamine use was negatively correlated with gray matter volume in bilateral frontal cortex, whereas the estimated total lifetime ketamine consumption was negatively correlated with gray matter volume in left superior frontal gyrus.
We have demonstrated a reduction in frontal gray matter volume in patients after chronic ketamine use. The link between frontal gray matter attenuation and the duration of ketamine use and cumulative doses of ketamine perhaps suggests a dose-dependent effect of long-term use of the drug. Our results have important connotations for the clinical picture that is likely to emerge with the growing recreational use of ketamine and is also relevant to the status of the drug as a model for schizophrenia.
Biological psychiatry 10/2010; 69(1):42-8. · 8.93 Impact Factor
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ABSTRACT: Ketamine abuse has been shown to have a deleterious impact on brain function. However, the precise mechanisms of ketamine dependence-induced pathological change remain poorly understood. Although there is evidence for white matter changes in drug abuse, the presence of white matter abnormalities in chronic ketamine users has not been studied. White matter volumes were measured using in vivo diffusion tensor magnetic resonance imaging data in 41 ketamine-dependent subjects and 44 drug-free healthy volunteers. White matter changes associated with chronic ketamine use were found in bilateral frontal and left temporoparietal cortices. There was also evidence that frontal white matter fractional anisotropy correlated with the severity of drug use (as measured by estimated total ketamine consumption). We provide direct evidence for dose-dependent abnormalities of white matter in bilateral frontal and left temporoparietal regions following chronic ketamine use. The findings suggest a microstructural basis for the changes in cognition and experience observed with prolonged ketamine use. Moreover, the similarities of these changes to those observed in chronic schizophrenia have implications for the glutamate model of this illness.
Brain 07/2010; 133(Pt 7):2115-22. · 9.46 Impact Factor
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ABSTRACT: Previous studies have shown that withdrawal from psychostimulant drugs such as d-amphetamine or methamphetamine decreases motivation to work for a natural reinforcement, which is thought to be associated with the withdrawal-induced depressive state and hypofunction of the mesolimbic dopamine system. However, to our knowledge, studies exploring the effect of morphine withdrawal on motivation for a natural reinforcement are lacking. The purpose of the present study was to examine whether motivation to work for a natural reinforcement changes during morphine withdrawal. Three groups of male Sprague–Dawley rats were trained to respond on a nose poke for a 4% sucrose solution under a progressive ratio schedule and were subsequently administered a 10-day regimen of injection of high or low dose of morphine or saline. Their duration of break point and withdrawal symptoms were assessed. The finding showed that break points were significantly reduced on day 1 and persisted to at least day 10 of withdrawal without change in locomotor activity. There were hardly any differences bear mentioning when comparing the magnitude of the decrease between the high- and the low-dose group, whereas the withdrawal scales were significant greater in the high-dose group than in the low-dose group. The results suggest that the morphine withdrawal resulted in decreased motivation to obtain the natural reinforcement. The progressive ratio procedure may be a useful technique for evaluation of changes in motivation for natural reinforcing stimuli following withdrawal from opiates.
Addiction Biology 05/2007; 12(2):152 - 157. · 4.83 Impact Factor
