Oscillatory Activities in Multiple Frequency Bands in Patients with Schizophrenia During Motion Perception.

Patients with schizophrenia show impairment in binding stimulus features into coherent objects, which are reflected in disturbed oscillatory activities. This study aimed to identify disturbances in multiple oscillatory bands during perceptual organization of motion perception in patients with schizophrenia. EEG was recorded from healthy controls and patients with schizophrenia during continuous presentation of a motion stimulus which induces reversals between two exogenously generated perceptions. This stimulus was used to investigate differences in motion binding processes between healthy controls and patients with schizophrenia. EEG signals were transformed into frequency components by means of the Morlet wavelet transformation in order to analyse inter-trial coherences (ITC) in the delta (1-4 Hz), theta (4-7 Hz), alpha (8-12 Hz), and gamma (28-48 Hz) frequency bands during exogenous motion binding. Patients showed decreased delta-ITC in occipital and theta-ITC in central and parietal areas, while no significant differences were found for neither alpha nor gamma-ITCs. The present study provides one of the first insights on the oscillatory synchronizations related with the motion perception in schizophrenia. The ITC differences revealed alterations in the consistency of large-scale integration and transfer functions in patients with schizophrenia.

What does the broken brain say to the neuroscientist? Oscillations and connectivity in schizophrenia, Alzheimer's disease, and bipolar disorder.

The application of the concept and methods of brain oscillations has been an important research area in neurosciences. In the last decades, besides the application in cognitive processes, the study of changes in brain oscillations in diseases has also become an important focal point of research. In the present paper, some remarkable examples in three different diseases are taken into consideration: 1) schizophrenia (SZ), 2) Alzheimer's disease (AD), 3) bipolar disorders (BD). In the current literature, decreased oscillations in cortical recordings are observed in most of the pathologies. For example, decrease of gamma activity in SZ, decrease of delta activity in almost all diseases, as well as frequency shifts in alpha and the lower frequencies were recorded. However, there are also paradoxical cases in which an increase of oscillatory activities is observed. In BD, whereas alpha activity is greatly decreased, a huge increase of beta activity is observed. Or, in SZ, a paradoxical increase of gamma activity can be observed during cognitive loading. We also observed paradoxical changes in the analysis of connectivity. In AD, we find that alpha, delta, and theta coherences between distant parts of the cortex are greatly decreased, whereas in the gamma band, event-related coherences attain very high values. The comparison of the results and paradoxical changes in diseases may lead to important conclusions related to the web of oscillations and neurotransmitters. In turn, we could gain new insights to approach "brain function", in general.

Alcohol Consumption in Healthy OPRM1 G Allele Carriers and Its Association with Impulsive Behavior.

AIMS: A link between alcohol use disorders (AUD) and impulsivity is well established. As there is evidence for the heritability of AUD, the investigation of the underlying genetic disposition for both conditions is an important issue. An association between AUD and a coding single nucleotide polymorphism (SNP) (rs1799971 encoding an Asn40Asp amino acid substitution, A118G) within the µ-opioid receptor 1 gene (OPRM1) has been reported. Therefore we tested the association between the OPRM1 A118G polymorphism and drinking as well as impulsive behavior in social drinkers. METHODS: A total of 214 healthy male social drinkers were recruited. Each participant was genotyped for the OPRM1 A118G variant. Alcohol use was assessed with items of the Alcohol Use Disorders Identification Test (AUDIT). Impulsivity was assessed using the UPPS impulsive behavior scale. For statistical analyses, we considered correlations, t-tests and ordinal regression models using SPSS V21. RESULTS: In total, 49 out of 214 participants were carriers of the OPRM1 118G allele. On average the OPRM1 118G carriers showed a slightly higher propensity for alcohol drinking. Higher drinking frequency among the G allele carriers was linked with higher urgency and perseveration subscores of impulsivity. CONCLUSION: Our results suggest a genetically influenced higher propensity for alcohol drinking among social drinkers carrying the 118G allele of the OPRM1 gene. The positive correlation between urgency and a higher drinking frequency among the OPRM1 118G hint towards a functional meaning of the opioid system in the regulation of impulsivity.

Association of functional DBH genetic variants with alcohol dependence risk and related depression and suicide attempt phenotypes: results from a large multicenter association study.

OBJECTIVE: Dopamine-beta-hydroxylase (DBH) metabolizes the conversion of dopamine to noradrenaline. DBH, located on chromosome 9q34.2 has variants with potential functional consequences which may be related to alterations of neurotransmitter function and several psychiatric phenotypes, including alcohol dependence (AD), depression (MD) and suicidal behavior (SA). The aim of this association study in a large multicenter sample of alcohol-dependent individuals and controls is to investigate the role of DBH SNPs and haplotypes in AD risk and associated phenotypes (AD with MD or SA). METHOD: 1606 inpatient subjects with DSM-IV AD from four addiction treatment centers and 1866 control subjects were included. Characteristics of AD, MD and SA were obtained using standardized structured interviews. After subjects were genotyped for 4 DBH polymorphisms, single SNP case-control and haplotype analyses were conducted. RESULTS: rs1611115 (near 5') C-allele and related haplotypes were significantly associated with alcohol dependence in females. This association with female alcohol dependence also accounts for the significant relationship between this variant and comorbid conditions and traits. CONCLUSIONS: This study presents evidence for a potentially functional DBH variant influencing the risk for alcohol dependence while other comorbid conditions are not independently influenced by this SNP. However, the study also supports the possible role of the dopamine system in the etiology of female alcohol dependence.

New rather than old? For working memory tasks with abstract patterns the P3 and the single-trial delta response are larger for modified than identical probe stimuli.

Memory-guided decision making is dynamic and context-dependent, even though many studies describe an enhancement of the P3 for recognized items in memory tasks ("old-new effect"). This study utilized a delay-dependent working memory task during which decision making could be optimized by focusing attention on detected changes instead of recognized similarities. Mean P3 amplitude and delta activity were analyzed from participants who classified probe stimuli as identical or modified. The P3 amplitudes were larger for modified than for identical probes, even when the probe occurred 4,000 ms after the primary stimulus. Enhanced single-trial amplitude, trial-by-trial consistency, and frontoparietal phase coherence of delta activity contributed to the larger P3 for the modified probe. Thus, context-dependent attentional resource allocation supporting memory-guided decisions might explain the enhancement of the P3 for specific probe types.

Event-related delta and theta brain oscillations reflect age-related changes in both a general and a specific neuronal inhibitory mechanism.

OBJECTIVE: ERPs may be limited in validity when investigating inhibitory functions in later adulthood, as age-related increases in intraindividual variability and changes in EEG-oscillations are not considered. The present study compared averaged ERP peak and single trial time-frequency (TF) data analysis. METHODS: Go/NoGo ERP waves amplitude/latency measures were compared with a TF analysis estimating single trial event-related EEG spectral power enhancement and intertrial phase-locking (ITC) in delta and theta band. RESULTS: Age-related larger ITC was found for theta oscillations in the N2-P3 time range during NoGo, only. Discrepancies between N1/N2 ERP and TF results were obtained. Go/NoGo-P3 amplitude reductions in elderly were not related to an increased delta latency jitter. CONCLUSIONS: Discrepancies between ERPs and TF results challenge conclusions made about age-related changes in Go/NoGo-N2. Earlier reports of age-related changes in P3 are supported by the present results. The study implies age-related impairments in a general neuronal inhibition mechanism and a specific response inhibition mechanism. SIGNIFICANCE: The study indicates long-range communication impairments in the aged brain and the results are discussed considering hypotheses on increases in neural noise.

No association of alcohol dependence with HOMER 1 and 2 genetic variants.

Several lines of evidence indicate that alterations of the central cortico-accumbens glutamate pathway are involved in the development and maintenance of alcohol- and substance-use disorders. The HOMER protein family is encoded by 3 genes HOMER (1-3) which are components of the excitatory postsynaptic density complex and function to modulate synaptic activity by the regulation of glutamate signaling. HOMER 1 and 2 have been reported to contribute to chronic alcohol-induced long-term neurochemical changes in the endogenous reward system. Data from animal models suggest a potential role of the Homer protein family in the development of alcohol and substance use. The aim of this study is to assess potential associations between HOMER 1 and 2 genetic variants in a larger sample of alcohol-dependent individuals and unrelated controls. Five genetic variants of HOMER 1 and 3 of HOMER 2 were genotyped in a multi-site sample of 1,923 German healthy controls and 2,039 alcohol-dependent subjects. Neither single SNP nor haplotype analysis could detect significant associations with alcohol dependence (AD) and related phenotypes. While most of the HOMER 1 and 2 SNPs are in low-to-moderate linkage disequilibrium, three major haplotypes of HOMER 1 and 4 haplotypes of HOMER 2 are present in the majority of alcohol-dependent and control subjects. In conclusion, our results suggest that single SNPs, respectively, haplotypes of the HOMER 1 and 2 genes are unlikely to play a major role in the pathophysiology of AD.

Association of a variant in the muscarinic acetylcholine receptor 2 gene (CHRM2) with nicotine addiction.

Genetic factors contribute to the overall risk of developing nicotine addiction, which is the major cause of preventable deaths in western countries. However, knowledge regarding specific polymorphisms influencing smoking phenotypes remains scarce. In the present study we provide evidence that a common single nucleotide polymorphism (SNP) in the 5' untranslated region of CHRM2, the gene coding for the muscarinic acetylcholine receptor 2 is associated with nicotine addiction. CHRM2 was defined as a candidate gene for nicotine addiction based on previous evidence that linked variations in CHRM2 to alcohol and drug dependence. A total of more than 5,500 subjects representative of the German population were genotyped and assessed regarding their smoking habits. The impact of three SNPs in CHRM2 on smoking behavior/nicotine addiction was investigated using logistic regression models or a quasi-Poisson regression model, respectively. We found the T allele of SNP rs324650 to be associated with an increased risk of smoking/nicotine dependence according to three different models, the recessive models of regular or heavy smokers vs. never-smokers (odds ratio 1.17 in both analyses) and according to the Fagerström index of nicotine addiction. In the analysis stratified by gender this association was only found in females. Our data provide further evidence that variations in CHRM2 may be associated with the genetic risk of addiction in general or with certain personality traits that predispose to the development of addiction. Alternatively, variations in CHRM2 could modulate presynaptic auto-regulation in cholinergic systems and may thereby affect an individual's response to nicotine more specifically.

Personality disorders in alcohol-dependent individuals: relationship with alcohol dependence severity.

The rate of axis II disorders in alcohol-dependent individuals is suggested to be high. The aim of this investigation is to assess the rate of DSM-IV axis II diagnoses in alcohol-dependent inpatients and their correlation with clinical characteristics of alcohol dependence (AD). 1,079 inpatients with DSM-IV AD from three inpatient addiction treatment centers ('qualified detoxification', open psychiatric university hospital wards) were included. Characteristics of AD were obtained using standardized structured interviews. Diagnoses of DSM-IV personality disorders (PDs) were generated with SCID-II-PQ and SCID-II interviews. Alcoholism severity was measured using the number of DSM-IV criteria endorsed and age at first drinking. Approximately 60% of the sample had at least one PD. However, rates of Axis II disorders differed significantly across centers. The most frequent PDs were obsessive-compulsive, borderline, narcissistic and paranoid PD. Diagnosis of any PD was related to a more severe clinical profile of AD. Regression analyses revealed that obsessive-compulsive PD was related to the number of DSM-IV criteria endorsed while antisocial PD was related to early age at first drinking. The majority of alcohol-dependent individuals had one or more comorbid axis II disorders. Univariate and multivariate analyses indicate that different PDs are related to age at first dinking and alcoholism severity.

Association of nicotinic acetylcholine receptor subunit alpha 4 polymorphisms with nicotine dependence in 5500 Germans.

Polymorphisms in the CHRNA4 gene coding the nicotinic acetylcholine receptor subunit alpha 4 have recently been suggested to play a role in the determination of smoking-related phenotypes. To examine this hypothesis, we conducted a genetic association study in three large samples from the German general population (N(1)=1412; N(2)=1855; N(3)=2294). Five single-nucleotide polymorphisms in CHRNA4 were genotyped in 5561 participants, including 2707 heavily smoking cases (regularly smoking at least 20 cigarettes per day) and 2399 never-smoking controls (

Altered oscillatory alpha and theta networks in schizophrenia.

In the present study we used a simple visual evoked potential and a visual oddball paradigm to investigate alterations in the temporal integration of different frequency components such as alpha and theta oscillations in patients with schizophrenia. We found that neither the amplitude enhancement after stimulus onset nor the intertrial phase coherence was generally reduced in patients, but that the topography of the neural response was altered. While healthy controls elicited their maximum early alpha as well as late theta response over posterior electrode sites, the maximum response in patients was shifted to anterior electrode positions. This result was not found for the late theta response for targets as target processing was accompanied with frontal theta amplitude enhancement in healthy controls as well. The change of the topographical response pattern was mirrored by the intertrial phase coherence in both frequency bands. The findings imply that schizophrenia is related to multiple alterations in oscillatory networks. Even during simple tasks without high cognitive demands dysfunctional mechanisms of temporal and regional coordination appear to be of importance in schizophrenia.

Potential pleiotropic effects of Mpdz on vulnerability to seizures.

We previously mapped quantitative trait loci (QTL) responsible for approximately 26% of the genetic variance in acute alcohol and barbiturate (i.e., pentobarbital) withdrawal convulsion liability to a < 1 cM (1.8 Mb) interval of mouse chromosome 4. To date, Mpdz, which encodes the multiple PSD95/DLG/ZO-1 (PDZ) domain protein (MPDZ), is the only gene within the interval shown to have allelic variants that differ in coding sequence and/or expression, making it a strong candidate gene for the QTL. Previous work indicates that Mpdz haplotypes in standard mouse strains encode distinct protein variants (MPDZ1-3), and that MPDZ status is genetically correlated with severity of withdrawal from alcohol and pentobarbital. Here, we report that MPDZ status cosegregates with withdrawal convulsion severity in lines of mice selectively bred for phenotypic differences in severity of acute withdrawal from alcohol [i.e., High Alcohol Withdrawal (HAW) and Low Alcohol Withdrawal (LAW) lines] or pentobarbital [High Pentobarbital Withdrawal (HPW) and Low Pentobarbital Withdrawal (LPW) lines]. These analyses confirm that MPDZ status is associated with severity of alcohol and pentobarbital withdrawal convulsions. Using a panel of standard inbred strains of mice, we assessed the association between MPDZ status with seizures induced by nine chemiconvulsants. Our results show that MPDZ status is genetically correlated with seizure sensitivity to pentylenetetrazol, kainate and other chemiconvulsants. Our results provide evidence that Mpdz may have pleiotropic effects on multiple seizure phenotypes, including seizures associated with withdrawal from two classes of central nervous system (CNS) depressants and sensitivity to specific chemiconvulsants that affect glutaminergic and GABAergic neurotransmission.

Raman investigation of stable and metastable states of 4-octyl-4'-cyanobiphenyl confined in porous silica matrices.

We study the polymorphism of solid phases of 4-octyl-4(')-cyanobiphenyl (8CB) by Raman spectroscopy. For bulk 8CB, the Raman spectrum of the CN stretch is featured by a single peak, which shifts abruptly at the smectic-A-crystal transition. In confinement, the CN peak splits both at high and low temperatures. In the isotropic and liquid crystal phases, the signature of the liquid crystal bulk (LC) coexists with another peak that is assigned to LC molecules interacting with the matrice interface. We find correlations between the volumic fractions of interfacial liquid and the texture of the matrices. At low temperatures, we assign the splitting of the CN peak to the coexistence of different metastable solid phases. For strong confinements, the temperature dependence of the CN stretching frequency extends to that of the liquid, which suggests the existence of frozen-in smecticlike solid phases. We discuss the structure of these metastable solid phases in the light of neutron diffraction measurements. We also report on the peculiar analogy between the effect of quenched disorder due to the porous matrices and the effect of thermal quenching.

Solid state polymorphism of liquid crystals in confined geometries.

Solid polymorphism of 4-alkyl-4'-cyanobiphenyl (nCB) was studied so far as a function of thermal history. In this paper we show that metastable solid phases of 4-octyl-4'-cyanobiphenyl (8CB) are also formed when the mesogens are confined in porous silica matrices and we study their structure by neutron diffraction and by Raman spectroscopy. Three metastable solid states are identified: one crystalline phase K', two frozen-in smectic-like phases K(s) and K'(s). We discuss the relation between the structure of the metastable solid phases and that of the mesomorph phases.

Serotonergic polymorphisms in patients suffering from alcoholism, anxiety disorders and narcolepsy.

1. Alterations in the serotonergic neurotransmission have been frequently described for patients suffering from alcoholism, anxiety disorders and narcolepsy. 2. The authors tested for association of the 5-HT2A receptor polymorphism (T102C) and the intron 7 tryptophan hydroxylase (TPH) polymorphism (A218C) among 176 alcohol dependent patients, 35 patients with panic disorder, 50 patients with generalized anxiety disorder, 55 patients with narcolepsy and 87 healthy controls. 3. Allele and genotype frequencies of the 5-HT2A receptor polymorphism (T102C), the intron 7 TPH polymorphism (A218C) were almost similar between the patients suffering from alcohol dependence, panic disorder, generalized anxiety disorder and narcolepsy. 4. There was no association between the 5-HT2A receptor polymorphism (T102C), the intron 7 TPH (A218C) polymorphisms and alcohol dependence, panic disorder, generalized anxiety disorder and narcolepsy in our subsets of German patients.

The HTR1B 861G>C receptor polymorphism among patients suffering from alcoholism, major depression, anxiety disorders and narcolepsy.

The HTR1B receptor gene has been linked to antisocial alcoholism in a Finnish population and an American Indian tribe [Lappalainen et al. , Arch. Gen. Psychiatry, 55 (1998) 989]. Using a candidate gene approach, we genotyped 209 patients with alcoholism, 108 patients with major depression, 32 patients with panic disorder, 50 patients with generalized anxiety disorder, 58 patients with narcolepsy and 74 healthy volunteers for the HTR1B 861G>C polymorphism. There was a higher frequency of the HTR1B 861G alleles among the alcohol-dependent patients as compared to the control subjects (chi(2)=4.02, d.f.=2, P=0.04). However, the association resulted from higher frequencies of the opposite alleles (HTR1B 861G), as originally reported by Lappalainen et al. (1998). Although the association in our study might be due to a type I error, the higher degree of HTR1B allele sharing within both populations could also argue for another alcoholism-relevant gene within the proximity of the HTR1B gene on human chromosome 6.

Sex differences in allelic frequencies of the 5-HT2C Cys23Ser polymorphism in psychiatric patients and healthy volunteers: findings from an association study.

Polymorphisms in the serotonergic system are believed to play a role in the etiology and treatment of different psychiatric illnesses. The 5-HT2C receptor gene is X-linked, with a frequent mutation at nucleotide 68 leading to a Ser-->Cys transition at amino acid 23. Recent studies have demonstrated an impaired function of 5-HT2C receptors and an increased production of the major noradrenergic metabolite 3-methoxy-4-hydroxyphenylethyleneglycol in the cerebrospinal fluid among the subjects carrying the Ser23 allele (Lappalainen et al., 1999). Biol. Psychiatry 46:821). We genotyped patients with alcohol dependence, panic disorder without agoraphobia, generalized anxiety disorder, narcolepsy and normal healthy volunteers for the 5-HT2C Cys23Ser polymorphism. 5-HT2C Cys23Ser allele frequencies and genotypes did not differ among patients with alcohol dependence, panic disorder, generalized anxiety disorder, narcolepsy and normal healthy volunteers. In an overall analysis, female subjects (n = 173) displayed a higher frequency of 5-HT2C Ser23 alleles as compared to males (n = 298, P = 0.0178). The potential mechanisms of the observed gender difference in allele frequencies, including transmission ratio distortion, are discussed.