Research Interests: Electrophysiology, Typography, Electroencephalography, Brain Mapping, Fourier Analysis, and 15 moreEvoked Potentials, Humans, Thalamus, Cerebral Cortex, Topography, Male, Young Adult, Coherence, Middle Aged, Adult, Fourier transform, Neural pathways, Alpha Rhythm, Theta Rhythm, and Functional Laterality
Research Interests:
Higher impulsivity observed in alcoholics is thought to be due to neurocognitive functional deficits involving impaired inhibition in several brain regions and/or neuronal circuits. Event-related Oscillations (EROs) offer time-frequency... more
Higher impulsivity observed in alcoholics is thought to be due to neurocognitive functional deficits involving impaired inhibition in several brain regions and/or neuronal circuits. Event-related Oscillations (EROs) offer time-frequency measure of brain rhythms during perceptual and cognitive processing, which provide a detailed view of neuroelectric oscillatory responses to external/internal events. The present study examines evoked power (temporally locked to events) of oscillatory brain signals in alcoholics during an equal probability Go/NoGo task, assessing their functional relevance in execution and inhibition of a motor response. The current study hypothesized that increases in the power of slow frequency bands and their topographical distribution is associated with tasks that have increased cognitive demands, such as the execution and inhibition of a motor response. Therefore, it is hypothesized that alcoholics would show lower spectral power in their topographical densities compared to controls. The sample consisted of 20 right-handed abstinent alcoholic males and 20 age and gender-matched healthy controls. Evoked delta (1.0-3.5Hz; 200-600ms), theta (4.0-7.5Hz; 200-400ms), slow alpha (8.0-9.5Hz; 200-300ms), and fast alpha (10.0-12.5Hz; 100-200ms) ERO power were compared across group and task conditions. Compared to controls, alcoholics had higher impulsiveness scores on the Barrett Impulsiveness Scale (BIS-11) and made more errors on Go trials. Alcoholics showed significantly lower evoked delta, theta, and slow alpha power compared to controls for both Go and NoGo task conditions, and lower evoked fast alpha power compared to controls for only the NoGo condition. The results confirm previous findings and are suggestive of neurocognitive deficits while executing and suppressing a motor response. Based on findings in the alpha frequency ranges, it is further suggested that the inhibitory processing impairments in alcoholics may arise from inadequate early attentional processing with respect to the stimulus related aspects/semantic memory processes, which may be reflected in lower posterio-temporal evoked fast alpha power. It can thus be concluded that alcoholics show neurocognitive deficits in both execution and suppression of a motor response and inadequate early attentional processing with respect to the semantic memory/stimulus related aspects while suppressing a motor response.
Research Interests:
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... more
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. Event-related potentials (ERPs) and current source density (CSD) during a monetary gambling task (MGT) were measured in 12-25year 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. HR offspring from older (16-25years) male and younger (12-15years) 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. 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. 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.
Research Interests:
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... more
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. METHODS: Healthy control subjects (n=58) and subjects with DSM-IV diagnosis of alcohol dependence (n=57) were assessed with a visual oddball task. Event-Related Potentials (ERPs) were recorded from 61 scalp electrodes and P3 amplitudes measured. Barratt Impulsiveness Scale (BIS), version 11, was used to evaluate impulsivity. Source localization of P3 was computed using low-resolution brain electromagnetic tomography (LORETA). RESULTS: Alcoholic subjects manifested reductions in target P3 amplitudes (p<0.0001...
Objective: Alcoholism has been considered to be part of a spectrum of disinhibitory disorders, with impulsivity being an important characteristic. Event-related potentials (ERPs) have been used as effective tools to study cognitive... more
Objective: Alcoholism has been considered to be part of a spectrum of disinhibitory disorders, with impulsivity being an important characteristic. Event-related potentials (ERPs) have been used as effective tools to study cognitive deficits related alcoholism and risk. Previous studies have reported low P3 amplitudes of the ERP and high impulsivity in alcoholics as well as in offspring who are at high risk (HR) to develop alcoholism. Our objective in the present study was to investigate the P3 component of the ERP as well as impulsivity in high risk subjects with a heavy loading of family history of alcoholism using an auditory oddball paradigm. Current source density (CSD) was also computed in each group to examine brain topography of P3 in these risk groups. Methods: Offspring in an adolescent age range (12-17 years) from HR families (N = 396) from the multi-site Collaborative Study on the Genetics of Alcoholism (COGA) and offspring from low risk (LR) control families (N = 79) wer...
Event-related oscillations (EROs) have served as a powerful tool to measure neurocognitive processing in normal and clinical populations including those with Alcohol Use Disorders (AUDs). Studies have reported reduced theta EROs during... more
Event-related oscillations (EROs) have served as a powerful tool to measure neurocognitive processing in normal and clinical populations including those with Alcohol Use Disorders (AUDs). Studies have reported reduced theta EROs during reward processing in alcoholics and individuals at risk for AUDs. Theta EROs to targets during a visual oddball task have been found to be significantly associated with several single nucleotide polymorphisms (SNPs) in KCNJ6 at genome-wide significant levels in a family genome-wide association study (GWAS). The KCNJ6 gene encodes GIRK2, a G-protein inward rectifying potassium channel that is important in regulating the excitability of neuronal networks, and has been shown to be involved in the pharmacokinetics of alcohol. The goal of the present study is to examine the effects of a synonymous KCNJ6 SNP (rs702859) on theta EROs during reward processing in a monetary gambling task. The sample included 1,601 individuals (800 males and 801 females) betwee...
The outcome related negativity (ORN), an event-related potential (ERP) component around 200-250 ms, has been suggested to be an electrophysiological brain signature for the processing of loss and gain. This component has been suggested to... more
The outcome related negativity (ORN), an event-related potential (ERP) component around 200-250 ms, has been suggested to be an electrophysiological brain signature for the processing of loss and gain. This component has been suggested to involve theta band oscillations as a primary feature. The aim of the current study is to examine oscillatory activity and functional connectivity between frontal and parietal regions during the processing of monetary loss and gain. The sample consisted of 36 healthy individuals with the age range of 18-35 years. A 64-channel EEG was recorded continuously while the subjects were performing a gambling task that prompted the subject to select one of two amounts, 10 and 50. Loss (-50) and Gain (+50) conditions were analyzed using a Wavelet coherence method for frontal (FZ) and parietal (PZ) regions. Time-Frequency representation and Power and Coherence were plotted and compared between loss and gain conditions. Loss condition had more power at FZ while...
Neurocognitive correlates of impulsivity have been thought to underlie several of externalizing/disinhibitory disorders including alcoholism. The current study examines the aspects of impulsivity in terms of behavioral measures as well as... more
Neurocognitive correlates of impulsivity have been thought to underlie several of externalizing/disinhibitory disorders including alcoholism. The current study examines the aspects of impulsivity in terms of behavioral measures as well as event-related oscillations (EROs) while performing a gambling task that involves monetary gain and loss. Behavioral measures of impulsivity were analyzed and brain oscillations were decomposed into time-frequency-amplitude data using the S-Transform algorithm. The mean amplitude in the outcome-related negativity (ORN) time window (225-275 ms) in each frequency band was statistically analyzed in both groups across four outcomes that involved valence (loss or gain) and magnitude (50 or 10 cents). Alcoholics showed higher impulsivity as measured in Barratt Impulsivity Scale (BIS) and in other task-related impulsivity responses. Further, alcoholics showed significantly decreased amplitude in delta (1-3 Hz) and theta (4-7 Hz) band during the ORN time wi...
The developmental trajectories of theta band (4-7Hz) event-related oscillations (EROs), a key neurophysiological constituent of the P3 response, were assessed in 2170 adolescents and young adults ages 12 to 25. The theta EROs occurring in... more
The developmental trajectories of theta band (4-7Hz) event-related oscillations (EROs), a key neurophysiological constituent of the P3 response, were assessed in 2170 adolescents and young adults ages 12 to 25. The theta EROs occurring in the P3 response, important indicators of neurocognitive function, were elicited during the evaluation of task-relevant target stimuli in visual and auditory oddball tasks. These tasks call upon attentional and working memory resources. Large differences in developmental rates between males and females were found; scalp location and task modality (visual or auditory) differences within males and females were small compared to gender differences. Trajectories of interregional and intermodal correlations between ERO power values exhibited increases with age in both genders, but showed a divergence in development between auditory and visual systems during ages 16 to 21. These results are consistent with previous electrophysiological and imaging studies...
Research Interests:
Background: Electrophysiological anomalies in individuals at risk for alcoholism have been previously reported using several tasks, including gambling paradigms. Studies have also identified deficits in reward processing as a key... more
Background: Electrophysiological anomalies in individuals at risk for alcoholism have been previously reported using several tasks, including gambling paradigms. Studies have also identified deficits in reward processing as a key cognitive component in alcoholism and as well as in predicting the risk to develop alcoholism. While reward processing deficits in alcoholics have been reported earlier, such anomalies in highrisk individuals have not been frequently studied. The goal of the present study is to elucidate patterns of current density activations during reward processing in individuals at high risk for developing alcoholism. Method: The sample comprised both male and female offspring from families in the Collaborative Study on the Genetics of Alcoholism (COGA) within the age range of 12-25 years; 742 high risk (HR) subjects who had at least one parent who was alcohol dependent and 428 low risk (LR) individuals without any parental history of alcohol dependence were included. S...
Objective: Alcoholism has been considered to be part of a spectrum of disinhibitory disorders, with impulsivity being an important characteristic. Previous studies have shown a correlation between impulsivity and cognitive deficits in... more
Objective: Alcoholism has been considered to be part of a spectrum of disinhibitory disorders, with impulsivity being an important characteristic. Previous studies have shown a correlation between impulsivity and cognitive deficits in alcoholics and in offspring who are at high risk (HR) to develop alcoholism. Event- related potentials (ERPs) have been used as an effective tool to study cognitive deficits in these populations. Our objective in the present study was to investigate the P300 component of the ERP as well as impulsivity in high risk subjects with a heavy loading of family history of alcoholism using an auditory oddball paradigm. Methods: Offspring from HR families (N=1785) from the multi-site Collaborative Study on the Genetics of Alcoholism (COGA) and offspring of low risk (LR) control families (N=152) were assessed with an Auditory Oddball Paradigm; P3 amplitudes to target stimuli were measured at midline frontal (Fz), central (Cz), parietal (Pz) and occipital (Oz) reg...
To examine the topographic relationship of P3(00) between the visual and auditory modalities, especially to examine whether there are any modality-specific hemispheric differences of P3 in normal adults. The P3s were recorded from the... more
To examine the topographic relationship of P3(00) between the visual and auditory modalities, especially to examine whether there are any modality-specific hemispheric differences of P3 in normal adults. The P3s were recorded from the same 41 normal right-handed males between the ages of 20 and 33 in both a typical auditory oddball task and a visual oddball paradigm with novel stimuli, with an extensive set of 61 scalp electrodes. In addition to the visual comparison and quantitative assessment of current source density (CSD) maps between the two modalities, canonical correlation analyses on the P3 raw amplitudes and examination of interaction effects of modality x location on both raw and normalized P3 data were performed. The canonical correlation between modalities was generally high, especially at the left parietal brain region. There were no significant hemispheric effects in anterior brain but significant left-greater-than-right hemispheric effects in posterior brain regions i...
Research Interests: Cognitive Science, Electroencephalography, Brain Mapping, Right Hemisphere Functions, Brain, and 15 moreHumans, Automation, Male, Clinical Sciences, Canonical Correlation, Adult, Auditory evoked Potentials, Interaction effect, Visual Evoked Potentials, Neurosciences, Right Handed, Current Source Density, Scalp, Surface Current, and Acoustic Stimulation
An event-related potential (ERP) correlate of visual short-term memory (VMP) has been identified in our laboratory. This study aims to determine how stimulus load modulates recognition processing of digits. ERPs were recorded from 117... more
An event-related potential (ERP) correlate of visual short-term memory (VMP) has been identified in our laboratory. This study aims to determine how stimulus load modulates recognition processing of digits. ERPs were recorded from 117 healthy right-handed subjects during a delayed matching-to-sample paradigm, using number stimuli that were either low load (three digits long) or high load (five digits long). The bootstrap method [R. Srebro, A bootstrap method to compare the shapes of two scalp fields, Electroenceph. Clin. Neurophysiol. 100 (1996) 25-32.] was employed to evaluate the topographic features of the VMP revealed in the current source density (CSD) maps. Response times were significantly shorter for matching stimuli than for non-matching stimuli only for low loads; longer response times were related to higher loads compared to low loads only for matching stimuli. The high loads were related to larger ERP responses. The ERP was significantly smaller for matching than for non...
Research Interests: Cognition, Brain and Cognitive Development, Memory, Evoked Potentials, Humans, and 14 moreFemale, Male, Spatial Pattern, Digit, Adult, Short Term Memory, Bootstrap Method, Visual Short Term Memory, Left Hemisphere, Electrodes, Right Handed, Current Source Density, Delayed Matching-to-Sample, and Scalp
The P3 event-related brain potential (ERP) is a positive-going voltage change of scalp-recorded electroencephalographic activity that occurs between 300-500 ms after stimulus onset. It is elicited when a stimulus is perceived, memory... more
The P3 event-related brain potential (ERP) is a positive-going voltage change of scalp-recorded electroencephalographic activity that occurs between 300-500 ms after stimulus onset. It is elicited when a stimulus is perceived, memory operations are engaged, and attentional resources are allocated toward its processing. Because this ERP component reflects fundamental cognitive processing, it has found wide utility as an assessment of human mental function in basic and clinical studies. In particular, P3 attributes are heritable and have demonstrated considerable promise as a means to identify individuals at genetic risk for alcoholism. We have conducted a quantitative linkage analysis on a large sample from families with a high density of affected individuals. The analyses suggest that several regions of the human genome contain genetic loci related to the generation of the P3 component of the ERP, which are possible candidate loci underlying the functional organization of human neur...
Research Interests:
The use of current source density (CSD), the Laplacian of the scalp surface voltage, to map the electrical activity of the brain is a powerful method in studies of cognitive and affective phenomena. During the last few decades, mapping of... more
The use of current source density (CSD), the Laplacian of the scalp surface voltage, to map the electrical activity of the brain is a powerful method in studies of cognitive and affective phenomena. During the last few decades, mapping of CSD has been successfully applied to characterize several neuropsychiatric conditions such as alcoholism, schizophrenia, depression, anxiety disorders, childhood/developmental disorders, and neurological conditions (i.e., epilepsy and brain lesions) using electrophysiological data from resting state and during cognitive performance. The use of CSD and Laplacian measures has proven effective in elucidating topographic and activation differences between groups: i) patients with a specific diagnosis vs. healthy controls, ii) subjects at high risk for a specific diagnosis vs. low risk or normal controls, and iii) patients with specific symptom(s) vs. patients without these symptom(s). The present review outlines and summarizes the studies that have employed CSD measures in investigating several neuropsychiatric conditions. The advantages and potential of CSD-based methods in clinical and research applications along with some of the limitations inherent in the CSD-based methods are discussed in the review, as well as future directions to expand the implementation of CSD to other potential clinical applications. As CSD methods have proved to be more advantageous than using scalp potential data to understand topographic and source activations, its clinical applications offer promising potential, not only for a better understanding of a range of psychiatric conditions, but also for a variety of focal neurological disorders, including epilepsy and other conditions involving brain lesions and surgical interventions.
Research Interests:
We describe a method to obtain estimates of EEG signal complexity using the well-established wavelet packet transform with best basis selection. In particular, we use the two-dimensional wavelet packet transform to obtain estimates of the... more
We describe a method to obtain estimates of EEG signal complexity using the well-established wavelet packet transform with best basis selection. In particular, we use the two-dimensional wavelet packet transform to obtain estimates of the complexity of two-dimensional images. This allows us to calculate complexity estimates of high-resolution brain potential maps generated from 61 scalp electrode Visual Oddball paradigm, grand-mean data. A significant reduction in the complexity of the surface Laplacian time-slices is observed during and after the Visual Potential 300 (P3) event for the target case, possibly as a result of increased spatial synchrony associated with visual-related tasks. We also present the results of a statistical analysis of the largest principal component of the time-varying complexity curves, for control, high-risk, and alcoholic groups of male subjects. Parametric and non-parametric analyses show differences in the complexity data which are significant between ...
Research Interests: Cognitive Science, Algorithms, Principal Component Analysis, Statistical Analysis, Electroencephalography, and 14 moreEntropy, Humans, Male, Reaction Time, Clinical Sciences, High Resolution, Theoretical Models, Reproducibility of Results, Auditory evoked Potentials, Wavelet Packet Transform, Electric Field, Neurosciences, Time varying, and Control Group
Adolescent drinking is an important public health concern, one that is influenced by both genetic and environmental factors. The functional variant rs1229984 in alcohol dehydrogenase 1B (ADH1B) has been associated at a genome-wide level... more
Adolescent drinking is an important public health concern, one that is influenced by both genetic and environmental factors. The functional variant rs1229984 in alcohol dehydrogenase 1B (ADH1B) has been associated at a genome-wide level with alcohol use disorders in diverse adult populations. However, few data are available regarding whether this variant influences early drinking behaviors and whether social context moderates this effect. This study examines the interplay between rs1229984 and peer drinking in the development of adolescent drinking milestones. One thousand five hundred and fifty European and African American individuals who had a full drink of alcohol before age 18 were selected from a longitudinal study of youth as part of the Collaborative Study on the Genetics of Alcoholism (COGA). Cox proportional hazards regression, with G × E product terms in the final models, was used to study 2 primary outcomes during adolescence: age of first intoxication and age of first D...
Research Interests: Psychology, Adolescent, Humans, Child, Alcoholism, and 17 moreUnited States, Female, Alcohol Drinking, Male, Young Adult, Social distance, Social Environment, Risk factors, Clinical Sciences, Peer group, Longitudinal Studies, Genetic variation, Disease Progression, Risk Factors, Neurosciences, Alcohol Dehydrogenase, and Proportional Hazards Models
Human brain oscillations represent important features of information processing and are highly heritable. A common feature of beta oscillations (13-28 Hz) is the critical involvement of networks of inhibitory interneurons as pacemakers,... more
Human brain oscillations represent important features of information processing and are highly heritable. A common feature of beta oscillations (13-28 Hz) is the critical involvement of networks of inhibitory interneurons as pacemakers, gated by gamma-aminobutyric acid type A (GABA(A)) action. Advances in molecular and statistical genetics permit examination of quantitative traits such as the beta frequency of the human electroencephalogram in conjunction with DNA markers. We report a significant linkage and linkage disequilibrium between beta frequency and a set of GABA(A) receptor genes. Uncovering the genes influencing brain oscillations provides a better understanding of the neural function involved in information processing.
Research Interests:
Research Interests: Engineering, Genetics, Physics, Chemistry, Biology, and 29 moreAdolescent, Genome Wide Association Studies (GWAS), Medicine, Multidisciplinary, Multivariate Analysis, Lung Cancer, Humans, Substance Use, Smoking, Alcoholism, Female, Male, Nicotinic Acetylcholine Receptors, Nicotine Dependence, Young Adult, Risk factors, PLoS one, Alcohol dependence, Adult, Cross Section, Linkage Disequilibrium, Quantitative Trait Loci, Chronic obstructive pulmonary disease, Risk Factors, Cross Sectional Studies, Proportional Hazards Models, Age of Onset, Substance Use Disorder, and Age at Onset
Event-related oscillations (ERO) offer an alternative theoretical and methodological approach to the analysis of event-related EEG responses. The P300 event-related potential (ERP) is elicited through the superposition of the delta (1-3... more
Event-related oscillations (ERO) offer an alternative theoretical and methodological approach to the analysis of event-related EEG responses. The P300 event-related potential (ERP) is elicited through the superposition of the delta (1-3 Hz) and theta (3-7 Hz) band oscillatory responses. The cholinergic neurotransmitter system has a key function in modulating excitatory post-synaptic potentials caused by glutamate, and therefore influences P300 generation and the underlying oscillatory responses. Here we report significant linkage and linkage disequilibrium between target case frontal theta band, visual evoked brain oscillations and a single nucleotide polymorphism (SNP) from the cholinergic muscarinic receptor gene (CHRM2) on chromosome 7. We also demonstrate significant linkage disequilibrium between CHRM2 SNPs and target case parietal delta band visual evoked oscillations (LD P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). These findings were not observed for the equivalent non-target case data, suggesting a role for the CHRM2 gene in higher cognitive processing in humans.
Research Interests: Psychophysiology, Cognition, Electroencephalography, Adolescent, Glutamate, and 20 moreBrain, Humans, Alcoholism, Delta, Cognitive Process, Oscillations, Human Brain, Genetic linkage analysis, Aged, Middle Aged, Gene Polymorphism, Adult, Single Nucleotide Polymorphism, Parietal Lobe, Linkage Disequilibrium, Visual Evoked Potentials, Muscarinic Receptor, Frontal Lobe, Theta Rhythm, and Delta Rhythm
Research Interests: Psychophysiology, Electrophysiology, Cognition, Attention, Electroencephalography, and 25 moreAdolescent, Information Processing, Human Information Processing, Problem Solving, Brain Mapping, Brain, Evoked Potentials, Humans, Alcoholism, Female, Male, Mental processes, Delta, Cognitive Process, Vigilance, Oscillations, Electroencephalogram, Cognitive systems, Inhibitory Control, Middle Aged, Adult, Power Spectrum, Cognitive Model, Theta Rhythm, and Case Control Studies
This study examines the differences in beta (12-28 Hz) band power in offspring of male alcoholics from densely affected alcoholic families. We have attempted to investigate if the increase in beta power is a 'state' or... more
This study examines the differences in beta (12-28 Hz) band power in offspring of male alcoholics from densely affected alcoholic families. We have attempted to investigate if the increase in beta power is a 'state' or 'trait' marker for alcoholism. This study also explores the gender differences in the expression of this potential risk marker. Absolute beta power in three bands-beta 1(12-16 Hz), beta 2 (16-20 Hz), and beta 3 (20-28 Hz)-in the eyes closed EEG of 171 high risk (HR) subjects who were offspring of male alcoholics and 204 low risk (LR) subjects with no family history of alcoholism, were compared for each gender separately using a repeated measures analysis of variance design. Alcoholic and non-alcoholic subjects within the high risk group were compared using a repeated measures design as a follow-up analysis. The present study demonstrated increased beta power in the resting EEG of offspring of male alcoholics. Male HR subjects had higher beta 1 (12-...
Research Interests:
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... more
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. In contrast, significantly higher gamma band response for the non-target stimulus was observed in alcoholics compared to controls. It is suggested that the reduction in early evoked frontal gamma band response to targets may be associated with frontal lobe dysfunction commonly observed in alcoholics. This perhaps can be characterized by a deficient top-down processing mechanism.
Research Interests: Psychophysiology, Electroencephalography, Brain Mapping, Humans, Alcoholism, and 13 moreMale, Reaction Time, Oscillations, Gamma Band, Phase Locking, Adult, Top Down Processing, Analysis of Variance, Time Factors, Visual Evoked Potentials, Time Frequency Representation, Frontal Lobe, and Case Control Studies
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... more
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. Additionally, the HR group showed less differentiation between target and non-target stimuli in both frontal and parietal regions compared to the LR group, indicating difficulty in early stimulus processing, probably due to a dysfunctional frontoparietal attentional network. The results indicate that the deficient early evoked gamma band response may precede the development of alcoholism and could be a potential...
Research Interests: Psychophysiology, Electroencephalography, Adolescent, Humans, Alcoholism, and 14 moreMale, Oscillations, Gamma Band, Risk factors, Phenotype, Phase Locking, Parietal Lobe, Children of Alcoholics, Biological markers, Risk Factors, Visual Evoked Potentials, Time Frequency Representation, Frontal Lobe, and Gamma-Aminobutyric Acid
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... more
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.
Research Interests:
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... more
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 0.220 and 0.647 and were highly significant at all 38 electrode pairs for theta (3-7 Hz), low-alpha (7-9 Hz), high-alpha (9-12 Hz), low-beta (12-16 Hz), middle-beta (16-20 Hz) and high-beta (20-28 Hz) frequency bands. The heritabilities were the highest in the high-alpha and low-beta bands at most electrode pairs. The heritabilities were most variable across the head in the three beta bands. Other heritability patterns were also identified within each frequency band. Our results suggest that substantial proportions of the variability in the bipolar EEG measures are explained by genetic factors.
Research Interests:
A dysfunctional neural reward system has been shown to be associated with alcoholism. The current study aims to examine reward processing in male alcoholics by using event-related potentials (ERPs) as well as behavioral measures of... more
A dysfunctional neural reward system has been shown to be associated with alcoholism. The current study aims to examine reward processing in male alcoholics by using event-related potentials (ERPs) as well as behavioral measures of impulsivity and risk-taking.
Research Interests: Electrophysiology, Cognition, Electroencephalography, Risk Taking, Adolescent, and 16 moreReward, Brain Mapping, Brain, Evoked Potentials, Humans, Alcoholism, Gambling, Male, Young Adult, Middle Aged, Adult, Analysis of Variance, Psychiatric, Error Related Negativity, Impulsive behavior, and Psychiatric Status Rating Scales
Recent studies have linked alcoholism with a dysfunctional neural reward system. Although several electrophysiological studies have explored reward processing in healthy individuals, such studies in alcohol-dependent individuals are quite... more
Recent studies have linked alcoholism with a dysfunctional neural reward system. Although several electrophysiological studies have explored reward processing in healthy individuals, such studies in alcohol-dependent individuals are quite rare. The present study examines theta oscillations during reward processing in abstinent alcoholics. The electroencephalogram (EEG) was recorded in 38 abstinent alcoholics and 38 healthy controls as they performed a single outcome gambling task, which involved outcomes of either loss or gain of an amount (10 or 50¢) that was bet. Event-related theta band (3.0-7.0 Hz) power following each outcome stimulus was computed using the S-transform method. Theta power at the time window of the outcome-related negativity (ORN) and positivity (ORP) (200-500 ms) was compared across groups and outcome conditions. Additionally, behavioral data of impulsivity and task performance were analyzed. The alcoholic group showed significantly decreased theta power during...