Brain signatures of monetary loss and gain: outcome-related potentials in a single outcome gambling task.

This study evaluates the event-related potential (ERP) components in a single outcome gambling task that involved monetary losses and gains. The participants were 50 healthy young volunteers (25 males and 25 females). The gambling task involved valence (loss and gain) and amount (50 cent and 10 cent) as outcomes.

A novel non-parametric regression reveals linkage on chromosome 4 for the number of externalizing symptoms in sib-pairs.

In this report, we present results of a genome-wide linkage scan using as a phenotype the number of externalizing symptoms associated with alcohol use disorders. Subjects were collected by the Collaborative Study on the Genetics of Alcoholism project from families in which at least three first degree relatives were affected by alcohol dependence. We use a novel non-parametric regression method based on kernel smoothing for our analysis.

Family-based association analyses of alcohol dependence phenotypes across DRD2 and neighboring gene ANKK1.

Background: There is an extensive and inconsistent literature on the association of the dopamine D2 receptor gene (DRD2) with alcohol dependence. Conflicting results have been attributed to differences in the severity of the alcohol dependence phenotype across studies, failure to exclude related disorders from comparison groups, and artifacts of population-stratification. Recently the genetic polymorphism most widely analyzed in DRD2, Taq1A, has been discovered to reside in a neighboring gene, ankyrin repeat and kinase domain containing 1 (ANKK1), located 10 kb downstream from DRD2.

Genetic influences on bipolar EEG power spectra.

The EEG bipolar power spectra provide more localization than spectral measures obtained from monopolar referencing strategies, and have been shown to be useful endophenotypes of psychiatric disorders such as alcoholism. We estimated the additive genetic heritability of resting bipolar EEG power spectra in a large sample of non-twin sibling pairs. The corresponding heritabilities ranged between 0.

Reduced frontal lobe activity in subjects with high impulsivity and alcoholism.

Objective: Impulsivity is an important characteristic of many psychiatric disorders, including substance-related disorders. These disinhibitory disorders have a similar underlying genetic diathesis, with each disorder representing a different expression of the same underlying genetic liability. This study assessed whether there is a relationship between impulsivity and alcohol dependence, and their correlations with P3 (P300) amplitude, a proposed endophenotype of alcoholism.

Heritability of bipolar EEG spectra in a large sib-pair population.

The additive genetic heritability of both monopolar and bipolar EEG spectral power in a sample of 305 non-twin sibships comprising 690 individuals (age range 7-65) was estimated in order to investigate their regional variation. The heritabilities of the bipolar EEG spectral power ranged from 0.10 to 0.

Association of CHRM2 with IQ: converging evidence for a gene influencing intelligence.

The cholinergic neurotransmitter system is thought to be involved in many aspects of memory, attention, and higher cognition. In the Collaborative Study on the Genetics of Alcoholism (COGA) sample, we have previously reported linkage and association to the cholinergic muscarinic 2 receptor gene (CHRM2) on chromosome 7 with evoked EEG oscillations (Jones et al. 2004), providing evidence that this gene may be involved in human brain dynamics and cognition.

Delta and theta oscillations as risk markers in adolescent offspring of alcoholics.

Background: Visual P300 is consistently lower in alcohol-dependent individuals, their offspring and subjects at risk. Delta and theta event-related oscillations (ERO) are the major contributors to the P300 signal. The total and evoked power in delta and theta bands in the 300 to 700 ms post-stimulus window (corresponding to the zone of P300 maxima) was compared between adolescent offspring of alcoholics (high-risk) and age-matched normal controls (low-risk), to assess the utility of the risk markers.

Patterns of regional brain activity in alcohol-dependent subjects.

Background: Electroencephalographic (EEG) measures of hemispheric asymmetry in anterior brain activity have been related to a variety of indices of psychopathology and emotionality. However, little is known about patterns of frontal asymmetry in alcohol-dependent (AD) samples. It is also unclear whether psychiatric comorbidity in AD subjects accounts for additional variance in frontal asymmetry, beyond a diagnosis of AD alone.

High levels of dopamine D2 receptors in unaffected members of alcoholic families: possible protective factors.

Context: Predisposition to alcoholism is likely an interaction between genetic and environmental factors that confer vulnerability and protection. Alcoholic subjects have low levels of dopamine D(2) receptors in striatum, and increasing D(2) receptor levels in laboratory animals reduces alcohol consumption.

Objectives: To test whether high levels of D(2) receptors may be protective against alcoholism and whether this is mediated by their modulation of activity in orbitofrontal cortex and cingulate gyrus (regions involved in salience attribution, emotional reactivity, and inhibitory control).

S-transform time-frequency analysis of P300 reveals deficits in individuals diagnosed with alcoholism.

Objective: Decomposition of event-related potential (ERP) waveforms using time-frequency representations (TFR's) is becoming increasingly common in electrophysiology. The P300 potential is an important component of the ERP waveform and has been used to study cognition as well as psychiatric disorders such as alcoholism. In this work, we aim to further understand the nature of the event-related oscillation (ERO) components which form the P300 wave and how these components may be used to differentiate alcoholic individuals from controls.

Evoked gamma band response in male adolescent subjects at high risk for alcoholism during a visual oddball task.

This study investigates early evoked gamma band activity in male adolescent subjects at high risk for alcoholism (HR; n=68) and normal controls (LR; n=27) during a visual oddball task. A time-frequency representation method was applied to EEG data in order to obtain stimulus related early evoked (phase-locked) gamma band activity (29-45 Hz) and was analyzed within a 0-150 ms time window range. Significant reduction of the early evoked gamma band response in the frontal and parietal regions during target stimulus processing was observed in HR subjects compared to LR subjects.

A cholinergic receptor gene (CHRM2) affects event-related oscillations.

We report genetic linkage and association findings which implicate the gene encoding the muscarinic acetylcholine receptor M2 (CHRM2) in the modulation of a scalp-recorded electrophysiological phenotype. The P3 (P300) response was evoked using a three-stimulus visual oddball paradigm and a phenotype that relates to the energy in the theta band (4-5 Hz) was analyzed. Studies have shown that similar electrophysiological measures represent cognitive correlates of attention, working memory, and response selection; a role has been suggested for the ascending cholinergic pathway in the same functions.

Association of GABRA2 with drug dependence in the collaborative study of the genetics of alcoholism sample.

Results from twin studies suggest that overlapping genetic factors influence alcohol dependence and illicit drug dependence. Using data from the Collaborative Study on the Genetics of Alcoholism (COGA), we examined the association between 69 SNPs in the GABAA receptor gene cluster on chromosome 4 and marijuana and illicit drug dependence, individually, and as co-occurring phenotypes with alcohol dependence. Results suggested association between marijuana dependence and illicit drug dependence with SNPs in the GABRA2 gene.

Association of alcohol dehydrogenase genes with alcohol dependence: a comprehensive analysis.

Linkage evidence indicated that gene(s) located on chromosome 4q, in the region of the alcohol dehydrogenase (ADH) genes, affected risk for alcoholism. We genotyped 110 single nucleotide polymorphisms (SNPs) across the seven ADH genes and analyzed their association with alcoholism in a set of families with multiple alcoholic members, using the pedigree disequilibrium test. There was strong evidence that variations in ADH4 are associated with alcoholism: 12 SNPs were significantly associated.

Marital status, alcohol dependence, and GABRA2: evidence for gene-environment correlation and interaction.

Objective: The gene GABRA2 has been associated with the risk for alcohol dependence in independent samples. This article explores how this genetic risk factor interacts with marital status, another factor previously shown to be associated with the risk for alcohol dependence.

Method: Data from more than 1,900 male and female subjects from the Collaborative Study of the Genetics of Alcoholism (COGA) sample were analyzed.

The role of GABRA2 in risk for conduct disorder and alcohol and drug dependence across developmental stages.

We use findings from the behavior genetics literature about how genetic factors (latently) influence alcohol dependence and related disorders to develop and test hypotheses about the risk associated with a specific gene, GABRA2, across different developmental stages. This gene has previously been associated with adult alcohol dependence in the Collaborative Study of the Genetics of Alcoholism (COGA) sample [Edenberg, H. J.

Genetics of human brain oscillations.

In the last three decades, much emphasis has been placed on neural oscillations in vitro, in vivo, as well as in the human brain. These brain oscillations have been studied extensively in the resting electroencephalogram (EEG), as well as in the underlying evoked oscillations that make up the event-related potentials (ERPs). There are several approaches to elucidate the possible mechanisms of these brain oscillations.

Description of the data from the Collaborative Study on the Genetics of Alcoholism (COGA) and single-nucleotide polymorphism genotyping for Genetic Analysis Workshop 14.

The data provided to the Genetic Analysis Workshop 14 (GAW 14) was the result of a collaboration among several different groups, catalyzed by Elizabeth Pugh from The Center for Inherited Disease Research (CIDR) and the organizers of GAW 14, Jean MacCluer and Laura Almasy. The DNA, phenotypic characterization, and microsatellite genomic survey were provided by the Collaborative Study on the Genetics of Alcoholism (COGA), a nine-site national collaboration funded by the National Institute of Alcohol and Alcoholism (NIAAA) and the National Institute of Drug Abuse (NIDA) with the overarching goal of identifying and characterizing genes that affect the susceptibility to develop alcohol dependence and related phenotypes. CIDR, Affymetrix, and Illumina provided single-nucleotide polymorphism genotyping of a large subset of the COGA subjects.

Functional variant in a bitter-taste receptor (hTAS2R16) influences risk of alcohol dependence.

A coding single-nucleotide polymorphism (cSNP), K172N, in hTAS2R16, a gene encoding a taste receptor for bitter beta -glucopyranosides, shows significant association with alcohol dependence (P = .00018). This gene is located on chromosome 7q in a region reported elsewhere to exhibit linkage with alcohol dependence.

Amplitude modulation of gamma band oscillations at alpha frequency produced by photic driving.

Gamma band response to visual stimulation in humans has been observed to have both burst and resonance properties. Amplitude modulation of gamma activity at low frequencies has been seen in rat hippocampus and modeled in a number of forms. Significant amplitude modulation (p=0.

Endophenotypes successfully lead to gene identification: results from the collaborative study on the genetics of alcoholism.

The use of endophenotypes has been proposed as a strategy to aid gene identification efforts for complex phenotypes [Gottesman, I. I., and Shields J.

Event-related oscillations in offspring of alcoholics: neurocognitive disinhibition as a risk for alcoholism.

Background: Event-related oscillations (EROs) are increasingly being used to assess neurocognitive functioning in normal and clinical populations. The current study compares different frequency activities in offspring of alcoholics (OA) and in normal control subjects (NC) to examine whether the OA group exhibits any abnormality in oscillatory activity while performing a Go/NoGo task.

Methods: The S-transform algorithm was employed to decompose the electroencephalographic (EEG) signals into different time-frequency bands, and the oscillatory responses in the P300 time window (300-700 milliseconds) were statistically analyzed in both groups.

Suppression of early evoked gamma band response in male alcoholics during a visual oddball task.

We investigated the early evoked gamma frequency band activity in alcoholics (n=122) and normal controls (n=72) during a visual oddball task. A time-frequency representation method was applied to EEG data in order to obtain phase-locked gamma band activity (29-45 Hz) and was analyzed within a 0-150 ms time window range. Significant reduction of the gamma band response in the frontal region during target stimulus processing was observed in alcoholic compared to control subjects.

Alcoholism is a disinhibitory disorder: neurophysiological evidence from a Go/No-Go task.

Response inhibition is considered a core dimension in alcoholism and its co-existing disorders. The major objective of this study is to compare the magnitude and spatial distribution of ERP components during response activation and inhibition in alcoholics (N = 30) and normal controls (N = 30) using a visual Go/No-Go task. The results indicate that alcoholics manifest a decreased P3(00) amplitude during Go as well as No-Go conditions.