Visual P3 in Female Alcoholics

WOMEN'S USE OF ALCOHOL: NEUROBIOBEHAVIORAL CONCOMITANTS AND CONSEQUENCES

In this narrative review, we draw from historical and contemporary literature to explore the impact of alcohol consumption on brain and behavior among women. We examine three domains: 1) the impact of alcohol use disorder (AUD) on neurobiobehavioral outcomes, 2) its impact on social cognition/emotion processing, and 3) alcohol's acute effects in older women. There is compelling evidence of alcohol-related compromise in neuropsychological function, neural activation, and brain structure. Investigations of social cognition and alcohol effects in older women represent emerging areas of study. Initial analyses suggest that women with AUD show significant deficits in emotion processing, a finding also observed in older women who have consumed a moderate dose of alcohol. Critically, despite the long-recognized need for programmatic interrogation of alcohol's effect in women, studies with sufficient numbers of women for meaningful analysis represent a small proportion of the literature, constraining interpretation and generalization.

Examining impulsivity and risky decision making among school youth in balloon analogue risk task

BACKGROUND

Impulsivity trait as a risk factor which typically displayed in risk decision among school youth. This study aims to examine behavioral and cognitive problems of risky decision among Chinese young people aged 15-25 years. The balloon analogue risk task (BART) and event-related potential (ERP) were combine used to explore the neural mechanism of risky decision process whether infected by impulsivity trait.

METHODS

A total of 31 subjects were included, including 16 experimental subjects with risk behavior (RS), and 15 health control subjects with non-risk behavior (HC). BART were used to measure risk-taking propensity and ERP were to record in real time. RS vs. HC were compared to explain the relationship between impulsivity and risky decision.

RESULTS

Behavioral data in BART task shown that the RS subjects tended to make risky decisions. ERP results illustrate that P300 in RS subjects is more significant positive-going than HC that means dysfunction of cognitive control, and FRN in RS subjects is more negative-going than HC in negative feedback condition, which means individual with high impulsive would be more sensitive to unexpected outcome.

CONCLUSIONS

Impulsiveness is a risk factor for school adolescent, because RS subjects performed more risky decision than control group, the evidence indicate that individual with high impulsiveness would lead to be less sensitive to harmful consequences and more inclination to immediate rewards. Therefore, the inclination of risk taking can be powerfully informed by different levels of impulsiveness.

The P300 in alcohol use disorder: A meta-analysis and meta-regression

OBJECTIVE

The P300 ERP component is a marker of reduced capacity in alcohol use disorder (AUD) to engage attentional mechanisms and update memory representations. No meta-analysis to date has been completed comparing effect size estimates of auditory vs. visual stimuli in AUD. In addition, there is a lack of consensus on whether the P3b in women is reduced, or whether the P3a - an earlier, more frontally distributed component - is reduced in AUD.

METHODS

Strict inclusion criteria and data-analysis plans were implemented. Eligible studies needed to diagnose AUD using DSM or ICD-10 and exclude patients with any psychiatric co-morbidities. Data analysis was completed using a refined variance estimator of the random effects model.

RESULTS

Effect size estimates were large for both auditory (Hedges' g = 1.01, p = .056) and visual (Hedges' g = 0.77, p = .040) P300 amplitudes, but only marginally significant for the auditory modality. Auditory P300 latency was significantly increased in AUD patients (Hedges' g = 0.73, p = .027). The moderator analysis did not show significant sex differences for either auditory (p = .97) or visual (p = .45) P3b. Finally, the P3a was not reduced in patients with AUD (Hedges' g = 1.01; p = .59).

CONCLUSION

This meta-analysis clarifies important questions related to P300 in AUD. By resolving inconsistencies, it is hoped that this information will facilitate the design of futurestudies.

Differential neurophysiological correlates of information processing in Internet gaming disorder and alcohol use disorder measured by event-related potentials

Internet gaming disorder (IGD) shares clinical and neuropsychological features with alcohol use disorder (AUD), but few studies have identified the neurophysiological characteristics of IGD. We investigated the N100 and P300 event-related potentials (ERPs) in patients with IGD to compare them with those of patients with AUD and healthy controls (HCs). Twenty-six patients with IGD, 22 patients with AUD, and 29 HCs participated in this study. ERPs were acquired from young male adults during an auditory oddball task. Between-group differences in N100 and P300 were investigated separately using repeated-measures analysis of variance. Correlations between the ERP values and neurocognitive functioning of each group were examined. Both the IGD and AUD groups showed reduced P300 amplitudes at the midline central and parietal area compared with the HCs. The IGD exhibited reduced N100 amplitudes at the midline frontal area compared with the HCs. The reduced P300 were correlated with a higher spatial span error rate in the IGD. The reduced N100 and P300 were not correlated with Internet addiction severity scores in the IGD. These results indicate that IGD have abnormalities in the P300 comparable to those in AUD. Moreover, the reduction in N100 could be considered a candidate trait marker for IGD.

Sex differences in alcohol-related neurobehavioral consequences

In this chapter, we review existing research regarding sex differences in alcohol's effects on neurobehavioral functions/processes. Drawn largely from laboratory studies, literature regarding acute alcohol administration and chronic alcohol misuse is explored focusing on commonly employed neuropsychologic domains (e.g., executive function, visuospatial skills, learning and memory, gait and balance), neurophysiologic measures (e.g., electroencephalography and event-related potentials), and structural and functional neuroimaging (e.g., magnetic resonance imaging (MRI), functional MRI, diffusion tensor imaging, positron emission tomography, and magnetic resonance spectroscopy). To provide a historical perspective on the development of these questions, we have included reference to early and more recent research. Additionally, specific biases, knowledge gaps, and continuing controversies are noted.

Reward processing deficits and impulsivity in high-risk offspring of alcoholics: A study of event-related potentials during a monetary gambling task

BACKGROUND

Individuals at high risk to develop alcoholism often manifest neurocognitive deficits as well as increased impulsivity. The goal of the present study is to elucidate reward processing deficits, externalizing disorders, and impulsivity as elicited by electrophysiological, clinical and behavioral measures in subjects at high risk for alcoholism from families densely affected by alcoholism in the context of brain maturation across age groups and gender.

METHODS

Event-related potentials (ERPs) and current source density (CSD) during a monetary gambling task (MGT) were measured in 12-25 year old offspring (N=1864) of families in the Collaborative Study on the Genetics of Alcoholism (COGA) Prospective study; the high risk (HR, N=1569) subjects were from families densely affected with alcoholism and the low risk (LR, N=295) subjects were from community families. Externalizing disorders and impulsivity scores were also compared between LR and HR groups.

RESULTS

HR offspring from older (16-25 years) male and younger (12-15 years) female subgroups showed lower P3 amplitude than LR subjects. The amplitude decrement was most prominent in HR males during the loss condition. Overall, P3 amplitude increase at anterior sites and decrease at posterior areas were seen in older compared to younger subjects, suggesting frontalization during brain maturation. The HR subgroups also exhibited hypofrontality manifested as weaker CSD activity during both loss and gain conditions at frontal regions. Further, the HR subjects had higher impulsivity scores and increased prevalence of externalizing disorders. P3 amplitudes during the gain condition were negatively correlated with impulsivity scores.

CONCLUSIONS

Older male and younger female HR offspring, compared to their LR counterparts, manifested reward processing deficits as indexed by lower P3 amplitude and weaker CSD activity, along with higher prevalence of externalizing disorders and higher impulsivity scores.

SIGNIFICANCE

Reward related P3 is a valuable measure reflecting neurocognitive dysfunction in subjects at risk for alcoholism, as well as to characterize reward processing and brain maturation across gender and age group.

Understanding alcohol use disorders with neuroelectrophysiology

Neurocognitive deficits associated with impairments in various brain regions and neural circuitries, particularly involving frontal lobes, have been associated with chronic alcoholism, as well as with a predisposition to develop alcohol use and related disorders (AUDs). AUD is a multifactorial disorder caused by complex interactions between behavioral, genetic, and environmental liabilities. Neuroelectrophysiologic techniques are instrumental in understanding brain and behavior relationships and have also proved very useful in evaluating the genetic diathesis of alcoholism. This chapter describes findings from neuroelectrophysiologic measures (electroencephalogram, event-related potentials, and event-related oscillations) related to acute and chronic effects of alcohol on the brain and those that reflect underlying deficits related to a predisposition to develop AUDs and related disorders. The utility of these measures as effective endophenotypes to identify and understand genes associated with brain electrophysiology, cognitive networks, and AUDs has also been discussed.

Association between P3 event-related potential amplitude and externalizing disorders: a time-domain and time-frequency investigation of 29-year-old adults

This study determined whether time-domain P3 amplitude and time-frequency principal component (TF-PC) reductions are present in adulthood (age 29) when participants have largely passed through the age of heaviest substance misuse. Participants were assessed from age 17 through 29 for lifetime externalizing (EXT) disorders. EEG comparisons from three topographic regions were examined for P3 amplitude and TF-PCs at delta and theta frequency ranges. Significant P3 amplitude reductions were found in those with EXT for both regional and site-Pz analyses, with stronger effects observed the greater the EXT comorbidity. Reductions were also observed in all eight TF-PCs extracted, with a delta component yielding frontal effects not apparent in the time domain. Overall, results suggest that these brain measures continue, at age 29, to provide effective indices of EXT that potentially tap a neural substrate related to behavioral disinhibition.

Neurocognitive deficits in male alcoholics: an ERP/sLORETA analysis of the N2 component in an equal probability Go/NoGo task

In alcoholism research, studies concerning time-locked electrophysiological aspects of response inhibition have concentrated mainly on the P3 component of the event-related potential (ERP). The objective of the present study was to investigate the N2 component of the ERP to elucidate possible brain dysfunction related to the motor response and its inhibition using a Go/NoGo task in alcoholics. The sample consisted of 78 abstinent alcoholic males and 58 healthy male controls. The N2 peak was compared across group and task conditions. Alcoholics showed significantly reduced N2 peak amplitudes compared to normal controls for Go as well as NoGo task conditions. Control subjects showed significantly larger NoGo than Go N2 amplitudes at frontal regions, whereas alcoholics did not show any differences between task conditions at frontal regions. Standardized low resolution electromagnetic tomography analysis (sLORETA) indicated that alcoholics had significantly lower current density at the source than control subjects for the NoGo condition at bilateral anterior prefrontal regions, whereas the differences between groups during the Go trials were not statistically significant. Furthermore, NoGo current density across both groups revealed significantly more activation in bilateral anterior cingulate cortical (ACC) areas, with the maximum activation in the right cingulate regions. However, the magnitude of this difference was much less in alcoholics compared to control subjects. These findings suggest that alcoholics may have deficits in effortful processing during the motor response and its inhibition, suggestive of possible frontal lobe dysfunction.

The P300 event-related brain potential as a neurobiological endophenotype for substance use disorders: a meta-analytic investigation

Endophenotypes are intermediate phenotypes on the putative causal pathway from genotype to phenotype and can aid in discovering the genetic etiology of a disorder. There are currently very few suitable endophenotypes available for substance use disorders (SUD). The amplitude of the P300 event-related brain potential is a possible candidate. The present study determined whether the P300 amplitude fulfils two fundamental criteria for an endophenotype: (1) an association with the disorder (disease marker), and (2) presence in unaffected biological relatives of those who have the disorder (vulnerability marker). For this purpose, two separate meta-analyses were performed. Meta-analysis 1 investigated the P300 amplitude in relation to SUD in 39 studies and Meta-analysis 2 investigated P300 amplitude in relation to a family history (FH+) of SUD in 35 studies. The findings indicate that a reduced P300 amplitude is significantly associated with SUD (d=0.51) and, though to a lesser extent, with a FH+ of SUD (d=0.28). As a disease maker, the association between reduced P300 amplitude and SUD is significantly larger for participants that were exclusively recruited from treatment facilities (d=0.67) than by other methods (i.e., community samples and family studies; d=0.45 and 0.32, respectively), and larger for abstinent SUD patients (d=0.71) than for current substance users (d=0.37). Furthermore, in contrast to FH+ males, a P300 amplitude reduction seems not to be present in FH+ females (d=-0.07). Taken together, these results suggest that P300 amplitude reduction can be both a useful disease and vulnerability marker and is a promising neurobiological endophenotype for SUD, though only in males. Implications and future directions are discussed.

Event-related potentials during visual target detection in treatment-naïve active alcoholics

BACKGROUND

Reduced P3b event-related potentials (ERP) amplitude during visual target detection in alcoholics is a robust phenomenon. However, this finding is based primarily on samples of treated alcoholics, who comprise only about 25% of alcoholics. We studied visual target detection in a treatment-naïve alcohol-dependent sample (TNAD) versus age and gender comparable nonalcoholic controls (NAC) to investigate whether reduced P3 amplitudes generalize to TNAD.

METHODS

EEGs were recorded from 74 TNAD and 63 age and gender comparable NAC during visual target detection. ANOVA was applied at midline electrodes to amplitudes and latencies of N2 and P3 ERP components during target and rare nontarget conditions.

RESULTS

Treatment-naïve alcohol-dependent subjects had a modestly lower P3b amplitude (p=0.05) and a more robustly lower N2b amplitude (p=0.29). In the target condition, TNAD showed a significant reduction in P3b amplitude and a larger reduction in N2b amplitude, with these phenomena being independent of each other. Latencies to P3b, N2b, and P3a were earlier in TNAD than NAC, with this effect correlating with our reported effect of better attention in TNAD versus NAC.

CONCLUSION

The significant reduction in P3b amplitude in TNAD suggests that this phenomenon is present in TNAD, but dramatically smaller than that observed in treated samples (we reported an effect over 5 times as large in treated long-term abstinent alcoholics). The N2b amplitude reduction (not present in long-term abstinent alcoholics) may reflect the effects of active alcohol abuse. Finally, the shorter latencies of these components in TNAD is associated with better scores on tests of attention and may reflect compensatory attentional effort in the context of active drinking.

Reduced resource optimization in male alcoholics: N400 in a lexical decision paradigm

BACKGROUND

Event Related Potential (ERP) studies have highlighted some measures, notably P3 amplitude, that are associated with both state and trait deficits in alcoholism, while studies examining N400 amplitude in alcoholism are few. The present study aims to examine differences in the N400 component, an electrophysiological correlate of semantic priming, in event-related potentials from a lexical decision task in 87 alcohol dependent subjects and 57 community controls.

METHODS

 Each subject was presented with 300 stimuli sequentially in a quasi-randomized design, where 150 stimuli were words and 150 were non-words. The subjects made a lexical decision indicating the word/non-word status with a button press. Among the words, 50 words (primed) were always preceded by their antonyms (prime, n=50), whereas the remaining 50 words were unrelated. N400 amplitude and latency measures were compiled from ERPs to the primed and unprimed words. Corresponding reaction time (RT) and response characteristics were also analyzed.

RESULTS

Control subjects revealed a significant attenuation of the N400 response to the primed word when compared to the unprimed word. Significantly less attenuation was observed in alcohol dependent subjects. No significant group differences were seen for latency and behavioral measures. All subjects had slower RT for unprimed words compared to primed words; however significantly less RT savings between the unprimed and primed condition was noted for alcoholics.

CONCLUSIONS

 These results suggest a reduced flexibility in the cognitive networks and a lack of resource optimization in alcoholics. The reduced attenuation of N400 during the primed condition in the alcohol dependent subjects may reflect an inability to engage similar neuronal substrates associated with semantic relatedness as seen in the controls. As diminished N400 attenuation during priming is observed in both alcoholics and high risk subjects, it may be a marker of risk and a good endophenotype for alcoholism.

Brain electrophysiological endophenotypes for externalizing psychopathology: a multivariate approach

Abnormalities in electrophysiological measures of stimulus-evoked brain activity (including the P3 event-related potential (ERP) and its associated delta and theta time-frequency (TF) components), and intrinsic, resting state brain activity (including EEG in the beta frequency band) have each been associated with biological vulnerability to a variety of externalizing (EXT) spectrum disorders, such as substance use disorders, conduct disorder, and antisocial behavior. While each of these individual measures has shown promise as an endophenotype for one or more aspects of EXT, we proposed that the power to identify EXT-related genes may be enhanced by using these measures collectively. Thus, we sought to explore a multivariate approach to identifying electrophysiological endophenotypes related to EXT, using measures identified in the literature as promising individual endophenotypes for EXT. Using data from our large twin sample (634 MZ and 335 DZ, male and female same-sex pairs), and fitting multivariate biometric Cholesky models, we found that these measures (1) were heritable, (2) showed significant phenotypic and genetic correlation with a general vulnerability to EXT (which is itself highly heritable), (3) showed modest phenotypic and genetic correlation with each other, and (4) were sensitive to genetic effects that differed as a function of gender. These relationships suggest that these endophenotypes are likely tapping into neurophysiological processes and genes that are both common across them and unique to each-all of which are relevant to a biological vulnerability to EXT psychopathology.

Priming deficiency in male subjects at risk for alcoholism: the N4 during a lexical decision task

BACKGROUND

While there is extensive literature on the relationship between the P3 component of event-related potentials (ERPs) and risk for alcoholism, there are few published studies regarding other potentially important ERP components. One important candidate is the N4(00) component in the context of semantic processing, as abnormalities in this component have been reported for adult alcoholics.

METHOD

A semantic priming task was administered to nonalcohol dependent male offspring (18 to 25 years) of alcoholic fathers [high risk (HR) n = 23] and nonalcoholic fathers [low risk (LR) n = 28] to study whether the 2 groups differ in terms of the N4 component. Subjects were presented with 150 words and 150 nonwords. Among the words, 50 words (primed) were preceded by their antonyms (prime, n = 50), whereas the remaining 50 words were unprimed. For the analysis, N4 amplitude and latency as well as behavioral measures for the primed and unprimed words were considered.

RESULTS

A significant interaction effect was observed between semantic condition and group, where HR subjects did not show N4 attenuation for primed stimuli.

CONCLUSION

The lack of N4 attenuation to primed stimuli and/or inability to differentiate between primed and unprimed stimuli, without latency and reaction time being affected, suggest deficits in semantic priming, especially in semantic expectancy and/or postlexical semantic processing in HR male offspring. Further, it indicates that it might be an electrophysiological endophenotype that reflects genetic vulnerability to develop alcoholism.

Relationship between the P3 event-related potential, its associated time-frequency components, and externalizing psychopathology

P3 amplitude reduction (P3-AR) is associated with biological vulnerability to a spectrum of externalizing disorders, such as ADHD, conduct disorder, and substance use disorders. P3, however, is generally characterized as a broad activation involving multiple neurophysiological processes. One approach to separating P3-related processes is time-frequency (TF) analysis. The current study used a novel PCA-based TF analysis method to investigate relationships between P3, its associated TF components, and externalizing in a community-based sample of adolescent males. Results showed that 1) alone, P3 and each TF-PCA derived component could successfully discriminate diagnostic groups from controls, and 2) delta components in specific time ranges accounted for variance beyond that accounted for by P3. One delta component was associated with all diagnostic groups, suggesting it may represent a more parsimonious endophenotype for externalizing than P3-AR.

The P300 event-related potential and its possible role as an endophenotype for studying substance use disorders: a review

The concept of endophenotypes has gained popularity in recent years. This is because of the potential that endophenotypes provide of measuring objective trait markers that are simpler to access and assess than complex behavioral disease phenotypes themselves. The simplicity, ease of measurement and the putative links to the etiology of the disease in the study of an endophenotype has the potential promise of unraveling the genetic basis of the disease in question. Of the various proposed endophenotypes, the P300 component of the event-related potential has been used in studies on alcoholism, schizophrenia and externalizing disorders. The current state of knowledge regarding the concept of endophenotypes, P300 and the validity of P300 as an endophenotype with special reference to substance use disorders is discussed in this review. The implications of the above are discussed.

Genetic variations of the NR3A subunit of the NMDA receptor modulate prefrontal cerebral activity in humans

INTRODUCTION

Recently, a novel N-methyl-D-aspartate (NMDA) receptor subunit, NR3A, has been discovered in the brain. This subunit decreases NMDA receptor activity by modulating the calcium permeability of the receptor channel and current density in cortical cells. Because the NR3A is expressed in the human prefrontal cortex, we hypothesized that genetic variations of the NR3A subunit modulate prefrontal activation.

METHODS

Electromagnetic activity during selective attention (auditory oddball task with target processing) was measured in 281 healthy subjects. Genotyping of a missense variation (rs10989591, Val362Met) of the NR3A gene was performed.

RESULTS

Individuals carrying Val/Val genotype showed significantly reduced frontal P300 amplitudes compared with Met/Met subjects. Subsequent low-resolution electromagnetic source analysis revealed that this group difference is likely caused by reduced activation in the inferior frontal gyrus.

CONCLUSIONS

It was shown for the first time that the genetic constitution of the subunit composition of NMDA receptor regulation might be relevant for prefrontal information processing in humans. The results underline the pivotal role of glutamate in frontal lobe function and indicate that the NR3A subunit could be a plausible candidate gene for diseases with prefrontal dysfunctions.

BIS/BAS Sensitivity and the P300 Event-Related Brain Potential

Abstract. Both a reduced amplitude of the P300 event-related potential component and a highly impulsive personality are known to be strong predictive markers for substance abuse and related psychiatric disorders. Because of this common link to externalizing psychopathology, a significant negative association between the P300 amplitude and personality measures related to behavioral disinhibition is expected. The present study investigated correlations between the visual P300 amplitude and the personality dimensions of Behavioral Approach System (BAS) sensitivity and Behavioral Inhibition System (BIS) sensitivity among healthy subjects (N = 44; mean age = 24 ± 4.93 years). To measure BIS and BAS sensitivity the BIS/BAS scales were used. Significant positive correlations were found between BAS sensitivity and P300 amplitude at both anterior and posterior scalp locations above the right hemisphere. There were no significant correlations between P300 amplitude and BIS sensitivity. Results are discussed in light of the rather inconsistent findings from previous studies investigating P300 amplitude and impulsivity-related measures. It is concluded that a P300 amplitude reduction may be regarded as a general, nonspecific marker for psychopathology and psychopathology-prone personality functioning.

Visual P300s in long-term abstinent chronic alcoholics

BACKGROUND

Evidence of reduced P3b amplitudes in chronic alcoholics and individuals at risk for developing alcoholism suggest that the P3b may be an endophenotypic marker for alcoholism. If this is the case, then long-term abstinent alcoholics (LTAAs) should exhibit reduced P3b amplitudes. Thus far, P3b studies on chronic alcoholics have focused primarily on samples with relatively short-term abstinence (less than 15 months). This study examines the amplitude and latency of the P3b and P3a event-related brain electrical components in LTAAs compared with normal controls (NCs) and whether these measures are related to alcohol use and other subject variables.

METHODS

Electroencephalographs (EEGs) were recorded on 48 LTAAs (mean abstinence=6.7 years) compared with 48 age-matched and gender-matched NCs during a visual P300 experiment consisting of standard, target, and rare nontarget conditions. This paradigm elicited the P3b (target condition) and the P3a (rare nontarget condition) components.

RESULTS

Long-term abstinent alcoholics had reduced P3b amplitudes and increased P3b latencies in comparison with NCs. Long-term abstinent alcoholics also exhibited delayed P3a components, but no P3a amplitude reductions. Alcohol use variables, a family history of alcohol problems, and the duration of alcohol abstinence were not associated with any amplitude or latency variables.

CONCLUSIONS

Even after very prolonged abstinence, reduced P3b amplitudes are present in chronic alcoholics and are not associated with any family history or alcohol use variables. These results provide equivocal support for reduced P3b amplitude being an endophenotypic marker for alcoholism, but are also consistent with P3b being affected by a threshold of alcohol abuse, with the effect not resolving over long periods of abstinence.

Tobacco Use, Alcohol Dependence, and Cognitive Performance

Chronic alcohol abuse has long been associated with a mild, generalized pattern of cognitive decrements. However, it is important to note that problem drinking rarely occurs in isolation from abuse of other drugs. For people dependent upon alcohol, tobacco is one of the mostly commonly coabused substances. Recent research suggests that individuals with alcohol dependency may gravitate toward tobacco use, in part, because of the positive effects of nicotine on aspects of cognitive performance that may be compromised as a consequence of chronic alcohol misuse. In this article, the author focuses on the effects of nicotine on behavioral and electrophysiological indexes of cognitive performance, and the impact of these effects on alcohol-related cognitive decrements. The author discusses implications of these findings in the context of treatment and recovery of people with alcoholism.

The utility of neurophysiological markers in the study of alcoholism

OBJECTIVE

This review attempts to differentiate neuroelectric measures (electroencephalogram (EEG), event-related potentials (ERPs) and event-related oscillations (EROs)) related to acute and chronic effects of alcohol on the brain from those that reflect underlying deficits related to the predisposition to develop alcoholism and related disorders. The utility of these neuroelectric measures as endophenotypes for psychiatric genetics is evaluated.

METHODS

This article reviews the main findings of EEG and ERP abnormalities in alcoholics, offspring of alcoholics at high risk to develop alcoholism and the electrophysiological effects of alcohol on high risk compared to low-risk offspring. It highlights findings using EROs, a fast developing tool in examining brain function and cognition. It also reviews evidence of genetic findings related to these electrophysiological measures and their relationship to clinical diagnosis.

RESULTS

Many of these abnormal neuroelectric measures are under genetic control, may precede the development of alcoholism, and may be markers of a predisposition toward the development of a spectrum of disinhibitory conditions including alcoholism. Genetic loci underlying some neuroelectic measures that involve neurotransmitter systems of the brain have been identified.

CONCLUSIONS

Quantitative neuroelectric measures (EEG, ERPs, EROs) provide valuable endophenotypes in the study of genetic risk to develop alcoholism and related disorders.

SIGNIFICANCE

Genetic studies of neuroelectric endophenotypes offer a powerful strategy for identifying susceptibility genes for developing psychiatric disorders, and provide novel insights into etiological factors.

Spatial-anatomical mapping of NoGo-P3 in the offspring of alcoholics: evidence of cognitive and neural disinhibition as a risk for alcoholism

OBJECTIVE

The concept of disinhibition as a behavioral and biological trait has been considered to be involved in the etiology of alcoholism and its co-existing disorders. The magnitude and functional mapping of event-related potential P3(00) components were analyzed, in order to examine the possible response inhibition deficits in the offspring of alcoholics.

METHODS

The P3 components were compared between 50 offspring of alcoholics (OA) and a matched normal control group (NC) using a visual Go/NoGo task. The low-resolution electromagnetic tomography (LORETA) was used to analyze the functional brain mapping between groups.

RESULTS

The results indicated that the OA group manifested decreased P3 amplitude during the NoGo but not the Go condition compared to the NC group. The voxel-by-voxel analysis in LORETA showed group differences at several brain regions including prefrontal areas during the processing of NoGo but not Go signals.

CONCLUSIONS

The decreased NoGo-P3 suggests that cognitive and neural disinhibition in offspring of alcoholics may serve as a neurocognitive index for a phenotypic marker in the development of alcoholism and related disorders.

SIGNIFICANCE

Dysfunctional neural and response inhibition in the offspring of alcoholics perhaps provides an endophenotypic marker of risk for the development of alcoholism and related disorders.

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. The difference between Go and No-Go processing was more evident in controls than in alcoholics. The topography of current source density in alcoholics during the P3 response was found to be very different from that of normals, suggesting that alcoholics perhaps activated inappropriate brain circuitry during cognitive processing. The significantly reduced No-Go P3 along with the relatively less anteriorized CSD topography during No-Go condition suggests poor inhibitory control in alcoholics. It is proposed that the No-Go P3, the electrophysiological signature of response inhibition, can be considered as an endophenotypic marker in alcoholism.

Increased P3 Amplitudes Induced by Alcohol-Related Pictures in Patients With Alcohol Dependence

BACKGROUND

Alcohol craving, a key element in alcohol dependence, is recognized as being a kind of motivational or emotional state. It is meaningful in research and clinical practice involving alcohol dependence to explore ways of measuring alcohol craving. The aim of this study was to measure the P3 event-related potentials induced by alcohol-related pictures in patients with alcohol dependence; these potentials are considered to constitute a neuronal correlate of alcohol craving.

METHODS

On the basis of our previous study, six alcohol-related pictures and six neutral pictures were chosen as the visual stimuli. Each set of stimuli consisted of alcohol-related or neutral pictures as the target stimuli and same-sized checkerboards as the nontarget stimuli. The stimuli were presented by using the oddball paradigm for 300 msec, with an interstimulus interval of 1000 msec, in 12 controls and 16 abstinent patients with alcohol dependence. Each electroencephalography session consisted of three blocks: a practice block, a neutral block, and an alcohol-craving block.

RESULTS

The amplitudes of P3 elicited by the alcohol-related pictures were significantly larger than those elicited by the neutral pictures in the patients with alcohol dependence, whereas there was no significant difference according to the stimuli in the P3 amplitudes of controls. Repeated-measures ANOVA on the amplitudes of P3 revealed that there was a significant interaction effect of block by subject group.

CONCLUSIONS

These results suggest that event-related potentials can be used as a neuronal correlate of alcohol craving in alcohol-dependent patients. Future investigations will be needed to assess the frequency of relapse in the patients included in this study, to elucidate the meaning of the observed results with regard to the therapeutic outcomes.

Gene-environment interplay in alcoholism and other substance abuse disorders: expressions of heritability and factors influencing vulnerability

Factors that confer predisposition and vulnerability for alcoholism and other substance abuse disorders may be described usefully within the gene-environment interplay framework. Thus, it is postulated that heritability provides a major contribution not only to alcohol but also to other substances of abuse. Studies of evoked potential amplitude reduction have provided a highly suitable and testable method for the assessment of both environmentally-determined and heritable characteristics pertaining to substance use and dependence. The different personal attributes that may co-exist with parental influence or exist in a shared, monozygotic relationship contribute to the final expression of addiction. In this connection, it appears that personality disorders are highly prevalent co-morbid conditions among addicted individuals, and, this co-morbidity is likely to be accounted for by multiple complex etiological relationships, not least in adolescent individuals. Co-morbidity associated with deficient executive functioning may be observed too in alcohol-related aggressiveness and crimes of violence. The successful intervention into alcohol dependence and craving brought about by baclofen in both human and animal studies elucidates glutamatergic mechanisms in alcoholism whereas the role of the dopamine transporter, in conjunction with both the noradrenergic and serotonergic transporters, are implicated in cocaine dependence and craving. The role of the cannabinoids in ontogeny through an influence upon the expression of key genes for the development of neurotransmitter systems must be considered. Finally, the particular form of behaviour/characteristic outcome due to childhood circumstance may lie with biological, gene-based determinants, for example individual characteristics of monoamine oxidase (MAO) activity levels, thereby rendering simple predictive measures both redundant and misguiding.

Abnormal CNV in chronic heavy drinkers

OBJECTIVE

We used the contingent negative variation (CNV), a slow negative shift in the human electroencephalogram, to investigate the effects of heavy chronic alcohol use on frontal lobe function.

METHODS

Event-related potentials (ERPs) were recorded from 30 heavy drinkers (HD) and 30 age-, sex-, and education-matched light or non-drinkers (LD), using a classical two-stimulus reaction time (RT) paradigm. Structural magnetic resonance images and neuropsychological tests were also administered.

RESULTS

The amplitude of the late CNV was significantly reduced in HD relative to light drinkers. Moreover, diminished CNV amplitudes in HD appear to be closely related to the amount of recent alcohol consumption. There were no significant differences in neuropsychological measures of frontal lobe function and frontal lobe volume between light and HD. However, in HD, reduced late CNV amplitudes were associated with decreased frontal lobe gray matter volume and poor performance on the Trail Making Test B. In LD but not in HD, late CNV amplitude correlated positively with RT, suggesting that the late CNV reflects some aspect of motor and cognitive preparation.

CONCLUSIONS

The inverse relationships between frontal lobe gray matter volume, performance on the Trail Making Test B, and late CNV amplitude in HD suggest that the ERP abnormalities observed in the current study may be indices of alcohol-related damage to the frontal lobe. The lack of a significant relationship between CNV amplitude and RT in HD suggests that chronic heavy alcohol use may disrupt response preparation.

Depression and familial risk for substance dependence: a P300 study of young women

The present study evaluated the effects of depression and a family history of alcohol or substance dependence on P300 event-related potentials in young women aged 14 to 20 years. Of the 130 female subjects, 29 met DSM-III-R diagnostic criteria for a lifetime history of a Major Depressive Episode. Event-related electroencephalographic potentials were recorded from each subject while she performed a complex visual oddball task. Analyses indicated a decrement in P300 amplitude in the depressed group as compared to girls with no history of depression. No effects of family history of alcoholism or drug dependence were detected. Current source density analyses, utilizing a realistic head-shape boundary element model, indicated that the difference between the depressed and non-depressed groups was maximal in the right prefrontal region. These results provide further support for the notion that the cognitive difficulties associated with depression are subtle and best detected with sensitive neurophysiological indices, such as P300.

Auditory P3 in female alcoholics

BACKGROUND

The P3 (P300) has been considered to be a phenotypical marker of the risk for alcoholism. Although reductions in visual P3 in male and female alcoholics have been replicated, studies of auditory target P3 have been inconsistent. Our objective was to study the magnitude of auditory P3 reduction in female alcoholics and to establish the association between P3 reduction and alcoholism while taking into account comorbid depression and psychoactive drug dependence. The characteristics of P3 reduction were further examined by studying the reduction in family history-positive and -negative individuals.

METHODS

Auditory target P3s recorded from 61 scalp electrodes in female alcoholics (n = 71) were compared with P3s from female controls (n = 159) ranging in age from 18 to 50 years. The amplitudes and latencies were statistically analyzed, by using repeated-measures ANOVA, in six regional electrode arrays and at representative electrode sites, with age and comorbid depression as covariates. The effects of family density and clinical variables such as depression and drug dependence were also examined with correlation analysis.

RESULTS

Alcoholic women had significantly lower P3 amplitudes in all six regions and at midline electrode sites. The reductions were not associated with comorbid depression, as shown by low correlations and similar P3 amplitudes at Pz in female alcoholics with and without depression. The P3 amplitudes in women with a high family density were smaller than those in women with a low family density of alcohol dependence. Drug dependency did not influence P3 amplitude, as shown by similar responses in drug-dependent and non-drug-dependent alcoholic women.

CONCLUSIONS

These findings highlight the significance of P3 reductions associated with alcoholism in women, independently of comorbid depression. Family density effects further support the evidence that these findings are heritable. These results suggest that P3 can be considered as a phenotypical marker of vulnerability to alcoholism in women.

[ERPs (N200, P300 and CNV) in alcoholics: relapse risk assessment]

The cognitive event-related potentials were studied in a group of 55 alcoholic patients, paired in age and sex with a group of 18 control subjects, using a protocol oddball (visual and auditory) and a protocol VCN Go/Nogo. The N200 obtained using an auditory oddball paradigm had lower amplitude in alcoholics than in controls. A significant amplitude decrease of visual P300 was also observed in alcoholic male subjects. There was however no difference in auditory P300 between alcoholics and control subjects. Using a Go/Nogo paradigm, a significant difference on the final part of the VCN appears between alcoholic and pilot subjects. In addition, the longitudinal follow-up of the same alcoholic patients showed an electrophysiological profile that allowed dividing them into two different groups. On the initial recording (17 days after weaning), the auditory oddball P300 amplitude was significantly higher at Cz and Pz among patients who relapsed during the 3 months follow-up. The same effect appeared on the CNV protocol, where the amplitude of P300 was higher in patients who subsequently relapsed than for those who remained abstinent. Cognitive ERPs may be clinically useful to improve the prediction of risk of relapse among alcoholic patients.

Substance use disorders, externalizing psychopathology, and P300 event-related potential amplitude

We hypothesize the existence of an inherited predisposition for a spectrum of behaviors and traits characterized by behavioral disinhibition. This externalizing spectrum includes childhood disruptive disorders, antisocial behavior, substance use disorders, personality traits related to behavioral undercontrol, and the precocious expression of problem behavior. We further hypothesize that a genetically influenced central nervous system diathesis underlies this spectrum and is reflected in reduced P300 amplitude in a visual oddball event-related potential task. A review of evidence bearing on the model is derived from findings from the Minnesota Twin Family Study, a population-based, longitudinal investigation of twin youth. These findings indicate that the collection of attributes related to behavioral disinhibition is familial, heritable, and interrelated. Evidence supporting P3 amplitude reduction (P3-AR) as an index of genetic vulnerability for this externalizing spectrum includes its association with (a) familial risk for substance use and antisocial personality disorders, (b) diagnoses of childhood disruptive disorders and substance use disorders, (c) early onset of undersocialized behavior, and (d) quantitative phenotypes related to externalizing problems. In addition, the development of substance use disorders over a 3-year period is associated with P3-AR measured prior to their expression. These findings suggest that P3-AR indexes one aspect of the genetic diathesis for a spectrum of externalizing problem behavior.

Linkage and linkage disequilibrium mapping of ERP and EEG phenotypes

Linkage analyses of highly heritable electrophysiological phenotypes (EEG, ERP) that can potentially identify individuals at risk for alcoholism were performed on a large sample of families with a high density of alcohol dependence as part of the Collaborative Study on the Genetics of Alcoholism (COGA); these genetic findings are summarized. Quantitative trait loci (QTLs) were identified for several ERP characteristics (P300, N100, N400) and for the beta frequencies of the EEG where we report linkage and linkage disequilibrium at a GABA(A) receptor gene on chromosome 4. Genetic analyses of ERPs suggest that several regions of the human genome contain genetic loci related to the generation of N100, N400 and P300, which are possible candidate loci underlying the functional organization of human neuroelectric activity. The advent of genomics and proteomics and a fuller understanding of gene regulation, will open new horizons on the critical electrical events so essential for human brain function.