Yanhui Liao

Differences between smokers and non-smokers in regional gray matter volumes: a voxel-based morphometry study.

Magnetic resonance imaging (MRI) studies showed a link between chronic smoking and structural brain abnormalities. To date, little is known about the long‐term effects of smoking on gray matter deficiencies. MRI study was carried for 44 smokers and 44 matched non‐smokers to assess gray matter volume differences between the two groups. Decreased gray matter volumes were found in left thalamus, medial frontal cortex and anterior cingulate of smokers in comparison to controls. This voxel‐based morphometry study is showing reduction of regional gray matter volume in smokers, which might better guide future research into the pathogenesis of chronic smoking.

Frontal white matter abnormalities following chronic ketamine use: a diffusion tensor imaging study

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.

Reduced Dorsal Prefrontal Gray Matter After Chronic Ketamine Use

BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.

Aberrant default mode functional connectivity in early onset schizophrenia.

Background The default mode network (DMN) has been linked to a number of mental disorders including schizophrenia. However, the abnormal connectivity of DMN in early onset schizophrenia (EOS) has been rarely reported. Methods Independent component analysis (ICA) was used to investigate functional connectivity (FC) of the DMN in 32 first-episode adolescents with EOS and 32 age and gender-matched healthy controls. Results Compared to healthy controls, patients with EOS showed increased FC between the medial frontal gyrus and other areas of the DMN. Partial correlation analyses showed that the FC of medial frontal gyrus significantly correlated with PANSS-positive symptoms (partial correlation coefficient  = 0.538, Bonferoni corrected P = 0.018). Limitations Although the sample size of participants was comparable with most fMRI studies to date, it was still relatively small. Pediatric brains were registered to the MNI adult brain template. However, possible age-specific differences in spatial normalization that arise from registering pediatric brains to the MNI adult brain template may have little effect on fMRI results. Conclusion This study provides evidence for functional abnormalities of DMN in first-episode EOS. These abnormalities could be a source of abnormal introspectively-oriented mental actives.

Abnormal anterior cingulum integrity in first episode, early-onset schizophrenia: a diffusion tensor imaging study.

Adolescents with early-onset schizophrenia (EOS) provide a unique opportunity to examine regional and disease-specific early abnormal brain development in schizophrenia. There is currently a general agreement that clinical symptoms and cognitive dysfunctions of schizophrenia may arise from a failure of adequate communication between different brain regions. This disturbed connectivity may be related to alterations in the numbers, distribution, and ultrastructural integrity of oligodendrocytes of white matter. Diffusion tensor imaging provides a relatively new approach for quantifying possible connectivity of white matter in vivo. In this study, thirty-eight adolescents with early-onset schizophrenia (EOS; onset of psychotic symptoms by age 18years) and 38 age- and gender-matched healthy volunteers received diffusion tensor imaging examinations. Fractional anisotropy images were compared between groups in the white matter using a voxelwise analysis after inter-subject registration to standard Montreal Neurological Institute (MNI) space. Adolescents with EOS demonstrated significantly reduced fractional anisotropy in right anterior cingulum compared to healthy volunteers. Increased fractional anisotropy was not observed in any brain region in patients compared to controls. ROI analysis also reported a trend-level negative correlation between mean regional FA in right anterior cingulum and PANSS positive symptom score. These findings indicate that white matter abnormalities in the anterior cingulum are associated with adolescent EOS.

Changes in brain gray matter in abstinent heroin addicts

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.

Symptoms of disordered eating, body shape, and mood concerns in male and female Chinese medical students.

OBJECTIVE This cross-sectional study explored the prevalence of disordered eating attitudes, body shape concerns, and social anxiety and depressive symptoms in male and female medical students in China. METHOD Four hundred eighty-seven students from Central South University (Hunan Province, Changsha City, China) completed the following self-report measures: Eating Attitudes Test-26, Eating Disorders Assessment Questionnaire, Body Shape Questionnaire, Swansea Muscularity Attitudes Questionnaire, Social Interaction Anxiety Scale, and the Self-Rating Depression Scale. RESULTS A comparatively lower rate of at-risk eating attitudes (2.5%) and eating disorders (0.90%) were found compared to those reported in other studies. Significantly more female (3.2%) than male (1.2%) students had abnormal eating attitudes with 4 female students meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for bulimia nervosa. Significant relationships were observed between eating attitudes, body shape concern, social anxiety, depression, and body mass index. For females, the most significant correlate of distorted eating attitudes was body shape concern, whereas for male students, social anxiety and concern with muscle size and shape were most strongly correlated with distorted eating attitudes.

Bilateral Fronto-Parietal Integrity in Young Chronic Cigarette Smokers: A Diffusion Tensor Imaging Study

Background 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. Methodology/Principal Findings 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). Conclusion/Significance 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.

Decrease in Temporal Gyrus Gray Matter Volume in First-Episode, Early Onset Schizophrenia: An MRI Study

Background Loss of gray matter has been previously found in early-onset schizophrenic patients. However, there are no consistent findings between studies due to different methods used to measure grey matter volume/density and influences of confounding factors. Methods The volume of gray matter (GM) was measured in 29 first episode early-onset schizophrenia (EOS) and 34 well-matched healthy controls by using voxel-based morphometry (VBM). Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). The correlations between the GM volume and PANSS scores, age of psychosis onset, duration of psychosis, and chlorpromazine (CPZ) equivalent value were investigated. Results Relative to healthy subjects, the patients with first episode EOS showed significantly lower GM volume in the left middle and superior temporal gyrus. The loss of GM volume negatively correlated with PANSS-positive symptoms (p = 0.002), but not with PANSS-negative symptoms, PANSS-general psychopathology, and PANSS-total score. No significant correlation was found between GM volume and age of psychosis onset, duration of psychosis, and CPZ equivalent value. Conclusion Patients with first episode EOS have evidence of reduced GM in the left middle and superior temporal gyrus. Structural abnormalities in the left middle and superior temporal gyrus may contribute to the pathophysiology of schizophrenia.

Genome-wide DNA methylation patterns in discordant sib pairs with alcohol dependence.

Alcohol dependence is a complex disease caused by a confluence of environmental and genetic factors. Epigenetic mechanisms have been shown to play an important role in the pathogenesis of alcohol dependence.