Variants Near CCK Receptors are Associated With Electrophysiological Responses to Pre-pulse Startle Stimuli in a Mexican American Cohort.

Neurophysiological measurements of the response to pre-pulse and startle stimuli have been suggested to represent an important endophenotype for both substance dependence and other select psychiatric disorders. We have previously shown, in young adult Mexican Americans (MA), that presentation of a short delay acoustic pre-pulse, prior to the startle stimuli can elicit a late negative component at about 400 msec (N4S), in the event-related potential (ERP), recorded from frontal cortical areas. In the present study, we investigated whether genetic factors associated with this endophenotype could be identified. The study included 420 (age 18-30 years) MA men (n = 170), and women (n = 250). DNA was genotyped using an Affymetrix Axiom Exome1A chip. An association analysis revealed that the CCKAR and CCKBR (cholecystokinin A and B receptor) genes each had a nearby variant that showed suggestive significance with the amplitude of the N4S component to pre-pulse stimuli. The neurotransmitter cholecystokinin (CCK), along with its receptors, CCKAR and CCKBR, have been previously associated with psychiatric disorders, suggesting that variants near these genes may play a role in the pre-pulse/startle response in this cohort.

Decreases in energy and increases in phase locking of event-related oscillations to auditory stimuli occur during adolescence in human and rodent brain.

Synchrony of phase (phase locking) of event-related oscillations (EROs) within and between different brain areas has been suggested to reflect communication exchange between neural networks and as such may be a sensitive and translational measure of changes in brain remodeling that occur during adolescence. This study sought to investigate developmental changes in EROs using a similar auditory event-related potential (ERP) paradigm in both rats and humans. Energy and phase variability of EROs collected from 38 young adult men (aged 18-25 years), 33 periadolescent boys (aged 10-14 years), 15 male periadolescent rats [at postnatal day (PD) 36] and 19 male adult rats (at PD103) were investigated. Three channels of ERP data (frontal cortex, central cortex and parietal cortex) were collected from the humans using an 'oddball plus noise' paradigm that was presented under passive (no behavioral response required) conditions in the periadolescents and under active conditions (where each subject was instructed to depress a counter each time he detected an infrequent target tone) in adults and adolescents. ERPs were recorded in rats using only the passive paradigm. In order to compare the tasks used in rats to those used in humans, we first studied whether three ERO measures [energy, phase locking index (PLI) within an electrode site and phase difference locking index (PDLI) between different electrode sites] differentiated the 'active' from 'passive' ERP tasks. Secondly, we explored our main question of whether the three ERO measures differentiated adults from periadolescents in a similar manner in both humans and rats. No significant changes were found in measures of ERO energy between the active and passive tasks in the periadolescent human participants. There was a smaller but significant increase in PLI but not PDLI as a function of active task requirements. Developmental differences were found in energy, PLI and PDLI values between the periadolescents and adults in both the rats and the human participants. Neuronal synchrony as indexed by PLI and PDLI was significantly higher to the infrequent (target) tone compared to the frequent (nontarget) tone in all brain sites in all of the regions of interest time-frequency intervals. Significantly higher ERO energy and significantly lower synchrony was seen in the periadolescent humans and rats compared to their adult counterparts. Taken together these findings are consistent with the hypothesis that adolescent remodeling of the brain includes decreases in energy and increases in synchrony over a wide frequency range both within and between neuronal networks and that these effects are conserved over evolution.

Event-related Oscillations to Emotional Faces are Related to a History of Internalizing Disorders.

Event-related oscillations (EROs) may represent sensitive biomarkers or endophenotypes for disorders that underlie risk behaviors such as suicidal thoughts and actions. In this study, young adults of American Indian (AI) (n = 821) and Mexican American (MA) (n = 721) ancestry (age 18-30 yrs) were clinically assessed for internalizing and externalizing disorders, and an internalizing scale was generated by extracting core diagnostic items from 6 lifetime DSM5-compatible diagnoses (social phobia, panic disorder, agoraphobia, obsessive compulsive disorder, post-traumatic stress disorder, major depressive episode) and symptoms of suicidality. EROs were generated to sad, happy and neutral faces, and energy and phase locking of delta ERO oscillations were assessed in frontal areas. An increase in delta ERO energy was found in the frontal lead (FZ) following presentation of the sad facial expressions in those with a history of 10 or more internalizing symptoms compared to those with no symptoms. Increases in delta ERO energy in FZ were also associated with a diagnosis of major depressive disorder (MDD), but not with anxiety disorders or antisocial personality disorder/conduct disorders (ASP). Major depression was also associated with increases in cross-cortical phase-locking (FZ-PZ). A decrease in the percentage of correctly identified neutral faces also was seen among those with 10 or more internalizing symptoms compared to those without internalizing symptoms, and in those with anxiety disorders, but not in those with ASP or MDD as compared to their controls. These findings suggest ERO measures may represent important potential biomarkers of depressive disorders as well as risk indicators for suicidal behaviors.

N4 component responses to pre-pulse startle stimuli in young adults: relationship to alcohol dependence.

Both physiological and behavioral studies provide evidence to suggest that deficits in frontal cortical control circuits may contribute to the risk for developing alcohol dependence. Event-related potential (ERP) and eye blink responses to startle and short delay prepulse-plus-startle stimuli, and psychiatric diagnoses were investigated in young adult (age 18-30 years) men (n=135) and women (n=205) Mexican Americans. Women displayed a significant increase in the amplitude of the eye blink response to both the startle and pre-pulse-plus-startle stimuli. None of the psychiatric diagnoses were associated with differences in eye blink responses. ERP responses to the startle and prepulse-plus startle stimuli included a negative polarity wave at approximately 400 ms that was of the highest amplitude in the frontal leads (N4S). Women were found to have significantly higher amplitude N4S responses than men. Participants with alcohol dependence demonstrated significantly less inhibition and more facilitation of the N4S component by the pre-pulse stimuli. This finding was not associated with a diagnosis of: any other drug dependence disorder (including nicotine), anxiety or affective disorder, or conduct/antisocial personality disorder. The present study suggests that gender and a lifetime diagnosis of alcohol dependence may selectively contribute to this frontal late wave electrophysiological response to prepulse-plus-startle stimuli.

EEG alpha phenotypes: linkage analyses and relation to alcohol dependence in an American Indian community study.

BACKGROUND: Evidence for a high degree of heritability of EEG alpha phenotypes has been demonstrated in twin and family studies in a number of populations. However, information on linkage of this phenotype to specific chromosome locations is still limited. This study's aims were to map loci linked to EEG alpha phenotypes and to determine if there was overlap with loci previously mapped for alcohol dependence in an American Indian community at high risk for substance dependence. METHODS: Each participant gave a blood sample and completed a structured diagnostic interview using the Semi Structured Assessment for the Genetics of Alcoholism. Bipolar EEGs were collected and spectral power determined in the alpha (7.5-12.0 Hz) frequency band for two composite scalp locations previously identified by principal components analyses (bilateral fronto-central and bilateral centro-parietal-occipital). Genotypes were determined for a panel of 791 micro-satellite polymorphisms in 410 members of multiplex families using SOLAR. RESULTS: Sixty percent of this study population had a lifetime diagnosis of alcohol dependence. Analyses of multipoint variance component LOD scores, for the EEG alpha power phenotype, revealed two loci that had a LOD score of 3.0 or above for the fronto-central scalp region on chromosomes 1 and 6. Additionally, 4 locations were identified with LOD scores above 2.0 on chromosomes 4, 11, 14, 16 for the fronto-central location and one on chromosome 2 for the centro-parietal-occipital location. CONCLUSION: These results corroborate the importance of regions on chromosome 4 and 6 highlighted in prior segregation studies in this and other populations for alcohol dependence-related phenotypes, as well as other areas that overlap with other substance dependence phenotypes identified in previous linkage studies in other populations. These studies additionally support the construct that EEG alpha recorded from fronto-central scalp areas may represent an important endophenotype associated with alcohol and other substance dependence.

A case study of participatory action research in a public new England middle school: empowerment, constraints and challenges.

PAR recognizes teachers and students as co-creators in a learning process that builds self-efficacy essential to long-term educational success. In enabling contexts, PAR projects also allow teachers to critically deconstruct societal power, examine how these dynamics are reproduced in the classroom, and work against the silencing of student voices. This case study describes the process of implementing an inquiry-based PAR model into a formal urban middle school program intended to reduce drop out rates. The anthropologist/researchers employed participant observation, interviews, and review of student work to explore the dynamics, challenges, and constraints confronted during the process. The intervention demonstrated the gap between practice and theory in a middle school environment marked by well-defined hierarchies and roles as well as high-stakes testing.

Delta Event-Related Oscillations Are Related to a History of Extreme Binge Drinking in Adolescence and Lifetime Suicide Risk.

Alcohol exposure typically begins in adolescence, and heavy binge drinking is associated with health risk behaviors. Event-related oscillations (EROs) may represent sensitive biomarkers or endophenotypes for early alcohol exposure as well as other risk behaviors such as suicidal thoughts and actions. In this study, young adults (age 18-30 years) of American Indian (AI) (n = 479) and Mexican American (MA) (n = 705) ancestry were clinically assessed, and EROs were generated to happy, sad and neutral faces. Extreme adolescent binge drinking (10+ drinks) was common (20%) in this population of AI/MA and associated with a significantly increased risk of a lifetime history of suicidal acts (SA, suicide attempts, deaths) but not suicidal thoughts (ST, ideation, plans). ST were reported among MA participants, whereas SA were more common among AI young adults. Extreme adolescent binge drinking was also associated with errors in detection of sad and neutral faces, increases in delta ERO energy, and decreases in phase locking (PL), particularly in parietal areas. A lifetime history of ST was associated with increases in delta ERO energy and PL, whereas SA were associated with decreases in both. These studies suggest that ERO measures may represent important potential biomarkers of adolescent extreme binge drinking and risk for suicidal behaviors.

CR-19-0950: Event-related responses to alcohol-related stimuli in Mexican-American young adults: Relation to age, gender, comorbidity and "dark side" symptoms.

BACKGROUND: Electrophysiological variables may represent sensitive biomarkers of vulnerability to or endophenotypes for alcohol use disorders (AUD). METHODS: Young adults (age 18-30 yrs, n = 580) of Mexican American heritage were assessed with the Semi-Structured Assessment for the Genetics of Alcoholism and event-related oscillations (EROs) generated in response to a task that used pictures of objects, food, and alcohol-related and non-alcohol-related drinks as stimuli. RESULTS: Decreases in energy in the alpha and beta frequencies and higher phase synchrony within cortical brain areas were seen in response to the alcohol-related as compared to the non-alcohol-related stimuli. Differences in ERO energy and synchrony responses to alcohol-related stimuli were also found as a function of age, sex, AUD status and comorbidity. Age-related decreases in energy and increases in synchrony were found. Females had significantly higher energy and lower synchrony values than males. Participants with AUD had higher synchrony values specifically in the beta frequencies, whereas those with a lifetime diagnosis of conduct disorder and/or antisocial personality disorder had lower alpha power and synchrony, and those with any affective disorder had lower ERO energy in the beta frequencies. Those with substance-associated affective "dark-side" symptoms had slower reaction times to the task, lower energy in the beta frequencies, lower local synchrony in the theta frequencies, and higher long-range synchrony in the delta and beta frequencies. CONCLUSIONS: These findings suggest that EROs recorded to alcohol-related stimuli may be biomarkers of comorbid risk factors, symptoms and disorders associated with AUD that also can differentiate those with "dark-side symptoms".

P3 components of the event-related potential and marijuana dependence in Southwest California Indians.

Native Americans have some of the highest rates of marijuana use and abuse, yet neurobiological measures associated with addiction to marijuana in this population remain unknown. The present investigation evaluated associations between the P350 and P450 components of the event-related potential (ERP) elicited by affective stimuli, and marijuana dependence in a population of Southwest California (SWC) Indian adults. Three hundred and seventeen participants with a mean age of 30 years who were free of major Axis I and psychiatric diagnoses and antisocial personality disorder were categorized as: (1) no marijuana use disorders or other drug dependence diagnoses; (2) marijuana dependence and no other drug dependence diagnoses; and (3) marijuana dependence and other drug dependence diagnoses. ERPs were collected using a facial discrimination task that generated a late positive component with two peaks at approximately P350 and P450 milliseconds. Multivariate analyses of variance was used to detect associations between the two component peaks and the three participant groups taking into consideration age, gender and the presence of a lifetime diagnosis of alcohol dependence. Increases in the latency of both the P350 and P450 component peaks were found to be associated with the diagnosis of marijuana dependence and marijuana dependence co-morbid with other drug dependence. Women appeared to be more impacted than men are. A diagnosis of marijuana dependence was not associated with any changes in late component amplitudes. Taken together these studies suggest that marijuana dependence may be associated with delays in the evaluation and identification of emotional stimuli in SWC Indians.

P3 components and adolescent binge drinking in Southwest California Indians.

In adolescence, consuming a large number of drinks over a short interval of time (e.g. binging) is not an uncommon occurrence. Since adolescence is an important neurodevelopmental period, the effect of binge drinking on brain and behavior has become a significant health concern. The present study evaluated event-related potentials (ERPs) in young adult Southwest California Indians who had a history of binge drinking during their adolescence. One hundred twenty five participants who were currently 18-25 yrs of age who were free of Axis I psychiatric diagnoses were categorized as: 1) reporting no binge drinking during adolescence (>5 drinks per occasion before age 18) or drug dependence diagnoses 2) reporting binge drinking during adolescence with no drug dependence diagnoses 3) reporting binge drinking during adolescence and drug dependence diagnoses. ERPs were collected using a facial discrimination task. Adolescent alcohol and drug exposure was found to be associated with decreases in the latency of an early P3 component (P350). Decreases in a later component amplitude (P450) were also found in young adults exposed to alcohol, and those exposed to alcohol and drugs. However, that finding appears to be a combined result of predisposing factors such as family history of alcoholism and presence of other externalizing diagnoses. Taken together these preliminary studies suggests that adolescent binge drinking may result in a decreases in P3 component latencies and amplitudes perhaps reflecting a loss or delay in the development of inhibitory brain systems.

Association of EEG alpha variants and alpha power with alcohol dependence in Mexican American young adults.

Several studies support an association between electroencephalogram (EEG) voltage and alcohol dependence. However, the distribution of EEG variants also appears to differ depending on an individual's ethnic heritage, suggesting significant genetic stratification of this EEG phenotype. The present study's aims were to investigate the incidence of EEG alpha variants and spectral power in the alpha frequency range in Mexican American young adults based on gender, and personal and family history of alcohol dependence. Clinical ratings (high-, medium-, and low alpha voltage variants) and spectral characteristics of the EEG in the alpha frequency range (7.5-12 Hz) were investigated in young adult (age 18-25 years) Mexican American men (n=98) and women (n=138) who were recruited from the community. Nineteen percent (n=45) of the participants had a low-voltage alpha EEG variant, 18% had a high-voltage variant, and 63% had a medium-voltage variant. There were no significant differences in the distribution of the EEG variants based on family history of alcohol dependence. There was a significant relationship between gender and the three alpha variants (chi2=9.7; df=2; P<.008), and there were no male participants with alcohol dependence with high alpha variants (chi2=5.8; df=2; P<.056). Alcohol dependence, but not a family history of alcohol dependence, was associated with lower spectral power in the alpha frequency range in the right (F=4.4; df=1,96; P<.04) and left (F=5.3; df=1.96; P<.02) occipital areas in the men but not in the women. In conclusion, in this select population of Mexican American young adults, male gender and alcohol dependence are associated with an absence of high-voltage alpha variants and lower alpha power in the EEG. These data suggest that EEG low voltage, a highly heritable trait, may represent an important endophenotype in male Mexican Americans that may aid in linking brain function with genetic factors underlying alcohol dependence in this ethnic group.

Electrophysiological responses to affective stimuli in American Indians experiencing trauma with and without PTSD.

American Indians are at high risk for exposure to violence and other traumatic events, yet few studies have investigated posttraumatic stress disorder (PTSD) or its neurobiological consequences in Indian communities. In the present study, a sample of American Indians (n = 146) were given a structured diagnostic interview that additionally indexed traumatic life events and symptoms emerging following those events. Electroencephalogram (EEG) spectra and visual event-related potentials (ERPs) to happy, sad, and neutral faces were also recorded from each participant. Ninety-nine percent of the sample had experienced at least one category of trauma with the mean number being 5, 27% had experienced at least 8 categories, and 13% met DSM-IV criteria for PTSD. The PTSD group did not differ on any demographic or diagnostic variables from the larger sample. An electrophysiological signature for PTSD was found that included increases in high-frequency gamma activity (20-40 Hz, F = 8.7, P < 0.004) in frontal leads, higher N1 amplitudes to sad stimuli in frontotemporal leads (F = 12.4, P < 0.001, F = 5.0, P < 0.03), and longer latency P3 components to happy stimuli in midline, central, and right frontal leads (F = 4.7, P < 0.03; F = 4.1, P < 0.04; F = 4.0, P < 0.05). These findings were observed in participants with PTSD, but not in a group with equivalently high trauma counts. These findings suggest that PTSD is associated with EEG hyperarousal, higher attentional levels to sad stimuli, and slower processing of happy stimuli. They also partially confirm ERP data reported in combat victims with PTSD suggesting that PTSD may induce neurobiological consequences that transcend type of eliciting trauma as well as ethnic and cultural factors.

Co-morbidity of select anxiety, affective, and psychotic disorders with cannabis dependence in Southwest California Indians.

Cannabis dependence is co-morbid with psychiatric disorders in general population surveys, but whether co-morbidity exists in American Indian populations is unknown. The aim of this study was to assess co-morbidity between cannabis dependence and psychiatric disorders in a community sample of Southwest California (SWC) Indians. Demographic information and DSMIII- R diagnoses, including differentiation of independent and cannabis-induced psychiatric disorders, were obtained using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) developed for the Collaborative Study on the Genetics of Alcoholism (COGA) from 513 SWC Indian adults residing on contiguous reservations. Although SWC Indians in this sample had high rates of cannabis dependence (43% in men and 24% in women), cannabis-induced psychiatric disorders each occurred in 1% or less of the sample. No significant co-morbidity with independent psychiatric disorders was found. In SWC Indians, cannabis dependence may be less etiologically related to psychiatric disorders than in the general population.

Low voltage alpha EEG phenotype is associated with reduced amplitudes of alpha event-related oscillations, increased cortical phase synchrony, and a low level of response to alcohol.

Low voltage EEG (LVEEG) is a heritable phenotype that differs depending on ancestral heritage, yet its impact on brain networks and cognition remain relatively unexplored. In this study we assessed energy and task related phase locking of event-related oscillation (EROs), behavioral responses, measures of IQ and personality, and expected responses to alcohol in a large sample of individuals with LVEEG compared to those with higher voltage variants. Participants (n=762) were recruited from a Native American community and completed a diagnostic interview, the Quick Test, the Subjective High Assessment Scale Expectation Version (SHAS-E) and the Maudsley Personality Inventory. Clinical and spectral analyzed EEGs were collected for determination of the presence of a LVEEG variant. EROs were generated using a facial expression recognition task. Participants with LVEEG (n=451) were significantly more likely to be older, married and have higher degrees of Native American heritage but did not differ in gender, income or education. Individuals with LVEEG were also found to have decreased energy in their alpha EROs, increased phase locking between stimulus trials, and increased phase-locking between cortical brain areas. No significant differences in the cognitive tests, personality variables or alcohol dependence or anxiety diagnoses were found, however, individuals with LVEEG did report a larger number of drinks ever consumed in a 24-h period and a less intense expected response to alcohol. These data suggest that alpha power in the resting EEG is highly associated with energy and cortical connectivity measures generated by event-related stimuli, as well as potentially increased risk for alcohol use.

Role of vitamin D and calcium nutrition in disease expression and parathyroid tumor growth in primary hyperparathyroidism: a global perspective.

Since the classic description by Fuller Albright in the 1940s, primary hyperparathyroidism has evolved from a disease with classic signs and symptoms to a disease in search of symptoms! Since that time, two major events have occurred. First, in the United States, United Kingdom, and in most European countries, there has been a steady rise in the apparent incidence of the disease. Second, there has been a dramatic shift in the pattern of presentation. A majority of patients with primary hyperparathyroidism in countries with multichannel screening panels are asymptomatic. Skeletal and renal complications are uncommon, and osteitis fibrosa is rare. In contrast, the clinical presentation of primary hyperparathyroidism has changed very little in other regions such as the East, the Middle East, and some parts of the southern hemisphere over the same period of observation. Accordingly, we assessed the influence of vitamin D and calcium nutrition on the disease expression and parathyroid tumor growth in patients with primary hyperparathyroidism from different parts of the world. Between 1945 and 1950, both the prevalence of osteitis fibrosa and parathyroid tumor weight declined dramatically in the United States, coinciding with fortification of milk with vitamin D. In contrast, osteitis fibrosa and parathyroid tumor weight changed very little in parts of the world where vitamin D depletion is endemic. Furthermore, for a comparable degree of vitamin D depletion, Asian Indians have significantly larger tumors compared with Americans (3.95 +/- 2.23 vs. 0.66 +/- 2.84 g; p < 0.001). Within the United States, blacks have larger tumors compared with whites (0.78 +/- 2.87 vs. 0.58 +/- 2.78 g; p < 0.01). However, the slopes of regression between serum 25-hydroxyvitamin D, the best index of vitamin D nutrition, and parathyroid tumor weight, the best available index of parathyroid growth, were not significantly different between Asian Indians, whites, and blacks. We conclude that vitamin D and calcium nutrition of the population affect both the clinical expression and parathyroid tumor growth in patients with primary hyperparathyroidism. It will be of interest to see if the pattern of presentation of primary hyperparathyroidism changes when better nutritional policies are implemented in developing countries.

Randomized controlled clinical trial of surgery versus no surgery in patients with mild asymptomatic primary hyperparathyroidism.

Parathyroidectomy is the definitive therapy for patients with symptomatic primary hyperparathyroidism. However, the role of surgery in mild asymptomatic primary hyperparathyroidism remains controversial. Accordingly, we conducted a prospective, randomized, controlled clinical trial of parathyroidectomy to determine the benefits of surgery vs. adverse effects of no surgery. Fifty-three patients were randomly assigned to either parathyroidectomy (n = 25) or regular follow-up (n = 28). Bone mineral density (BMD), biochemical indices of the disease, quality of life, and psychological function were measured at 6- or 12-month intervals for at least 24 months. Twenty-three of the 25 patients randomized to parathyroidectomy had surgery within the specified time of the protocol and three of the 28 patients randomized to regular follow-up had parathyroidectomy during follow-up. After parathyroidectomy, there was an increase in BMD of the spine (1.2%/yr, P < 0.001), femoral neck (0.4%/yr, P = 0.031), total hip (0.3%/yr, P = 0.07), and forearm (0.4%/yr, P < 0.001) and an expected fall in serum total and ionized calcium, serum PTH, and urine calcium (P < 0.001 for all). In contrast, patients followed up without surgery lost BMD at the femoral neck (-0.4%/yr, P = 0.117) and total hip (-0.6%/yr, P = 0.007) but gained at the spine (0.5%/yr; P = ns) and forearm (0.2%/yr, P = 0.047), with no significant changes in biochemical indices of disease. Consequently, a significant effect of parathyroidectomy on BMD was evident only at the femoral neck (a group difference of 0.8%/yr; P = 0.01) and total hip (a group difference of 1.0%/yr; P = 0.001) but not at the spine (a group difference of 0.6%/yr) or forearm (a group difference of 0.2%/yr). Quality-of-life scores as measured by a 36-item short-form health survey showed significant declines in five of the nine domains (social functioning, physical problem, emotional problem, energy, and health perception) in patients followed up without surgery but in only one of the nine domains (physical function) in the patients who had parathyroidectomy. Consequently, a modest measurable benefit of parathyroidectomy was evident in social and emotional role function (P = 0.007 and 0.012, respectively). Psychological function as assessed by the symptom checklist revised did not change significantly in either group, except for a significant decline in anxiety (P = 0.003) and phobia (P = 0.024) in patients who had surgery in comparison with those who did not. We conclude that it is feasible to conduct a randomized, controlled clinical trial of parathyroidectomy in patients with mild asymptomatic primary hyperparathyroidism, and measurable benefits of surgery on BMD, quality of life, and psychological function can be demonstrated. However, the small but significant benefits of parathyroidectomy must be weighed against the risks of surgery in these otherwise healthy individuals.

EEG alpha variants and alpha power in Hispanic American and white non-Hispanic American young adults with a family history of alcohol dependence.

Results from several studies support associations among variants in electroencephalogram (EEG) alpha voltage, alcohol dependence, ethnic heritage, and a family history of alcohol dependence, although no studies have as yet been conducted in individuals of Hispanic ethnicity. Categorization of EEG, by using spectral analyses, into high-, medium-, and low-voltage alpha, as well as absolute EEG power in alpha and beta frequency ranges, was carried out for Hispanic American (n=108) and white non-Hispanic American (n=269) young adult men and women (age range, 18 to 25 years) who had a family history, but no personal history, of alcohol dependence. Eighteen percent (n=70) of the participants were categorized as having a low-voltage alpha EEG, 16% had high-voltage alpha, and 64% had medium-voltage alpha. In comparison with findings for men, women were found to have higher overall power in the low frequency alpha (7.5-9 Hz) and beta (12-20 Hz, 20-50 Hz) frequency ranges. Hispanic Americans had a lower percentage of individuals in the low-voltage alpha group (9%) and more individuals in the medium-voltage alpha group (73%) compared with findings for white non-Hispanic Americans (low-voltage alpha, 19%; medium-voltage alpha, 62%). Results of the current study confirm the presence of ethnic stratification in EEG alpha variants.

EEG alpha and level of response to alcohol in Hispanic- and non-Hispanic-American young adults with a family history of alcoholism.

OBJECTIVE: A person's level of response to alcohol is associated with family history of alcoholism, ethnic heritage and electroencephalogram (EEG) phenotype. The present study's aims were to investigate EEG alpha and response to alcohol in Hispanic-American and non-Hispanic-American young adults. METHOD: EEG power in the slow and fast alpha frequency ranges (7.5-9 Hz, 9-12 Hz) was obtained at baseline and at 74 minutes following the administration of alcohol to Hispanic-American (n = 79) and white non-Hispanic-American (n = 208) young adult men and women (18-25 years old), all of whom had a family history but no personal history of alcohol dependence. Measures of breath alcohol concentrations and subjective responses to alcohol (Subjective High Assessment Scale [SHAS]) also were ascertained. RESULTS: Alcohol was found to produce significant effects on EEG power in the slow (F = 79.5, p < .0001) alpha frequency range. Although no overall effects of alcohol were found in the fast alpha frequency range, Hispanic participants had decreases in EEG fast alpha activity following alcohol administration, whereas non-Hispanics had alcohol-induced increases in power in this frequency range (F = 4.0, p < .04). EEG power, in the fast alpha frequency range (9-12 Hz) at baseline, also was found to be negatively associated with level of response to alcohol, as indexed by SHAS scores (F = 5.2, 2/283 df, p < .023). CONCLUSIONS: Previous studies in Native Americans, Asians and Euro-Americans have suggested genetic stratification in EEG response to alcohol as well as significant associations with family history of alcoholism. The present results extend previous studies to Hispanics and further confirm that increased EEG alpha power at baseline is predictive of a less intense response to alcohol, as indexed by the SHAS.

EEG spectral phenotypes: heritability and association with marijuana and alcohol dependence in an American Indian community study.

Native Americans have some of the highest rates of marijuana and alcohol use and abuse, yet neurobiological measures associated with dependence on these substances in this population remain unknown. The present investigation evaluated the heritability of spectral characteristics of the electroencephalogram (EEG) and their correlation with marijuana and alcohol dependence in an American Indian community. Participants (n=626) were evaluated for marijuana (MJ) and alcohol (ALC) dependence, as well as other psychiatric disorders. EEGs were collected from six cortical sites and spectral power determined in five frequency bands (delta 1.0-4.0 Hz, theta 4.0-7.5 Hz, alpha 7.5-12.0 Hz, low beta 12.0-20.0 Hz and high beta/gamma 20-50 Hz). The estimated heritability (h(2)) of the EEG phenotypes was calculated using SOLAR, and ranged from 0.16 to 0.67. Stepwise linear regression was used to detect correlations between MJ and ALC dependence and the spectral characteristics of the EEG using a model that took into account: age, gender, Native American Heritage (NAH) and a lifetime diagnosis of antisocial personality and/or conduct disorder (ASPD/CD). Increases in spectral power in the delta frequency range, were significantly correlated with gender (p<0.001) and marijuana dependence (p<0.003). Gender, age, NAH and ASPD/CD were all significantly (p<0.001) correlated with theta, alpha and beta band power, whereas alcohol dependence (p<0.01), gender (p<0.001), and ASPD/CD (p<0.001) were all correlated with high beta/gamma band power. These data suggest that the traits of EEG delta and high beta/gamma activity are correlated with MJ dependence and alcohol dependence, respectively, in this community sample of Native Americans.

EEG low-voltage alpha and alpha power in African American young adults: relation to family history of alcoholism.

BACKGROUND: Several studies support an association between having a low-voltage EEG and alcohol dependence; however, it is not clear whether this measure represents a risk marker or is a result of years of heavy drinking. The present study's aims were to investigate the prevalence of low-voltage alpha EEG variants in African American young adults who have not yet developed alcohol dependence and to test for associations between low-voltage alpha (LVA) EEG, alpha power, and a family history of alcohol dependence. METHODS: Clinical ratings and spectral characteristics of the EEG, collected using bipolar recordings, were investigated in 81 African American young adult men and women (18-25 years old) who had no personal history of alcohol dependence. Information on psychiatric diagnoses, personality features, personal drinking and drug use history, and family history (FH) of alcoholism was obtained. RESULTS: Thirty-two percent (n = 26) of the participants had an LVA EEG variant, and an additional 22% (n = 18) had borderline LVA. The presence of an LVA variant was not associated with drinking status, a family history of alcoholism, or a personal history of anxiety disorders but was associated with significantly higher extroversion scores. Participants who had an FH of alcoholism had significantly higher spectral power in the slow alpha frequencies (7.5-9 Hz). FH was not associated with any significant differences in any other EEG frequency band. CONCLUSIONS: These findings suggest that considerable ethic variation may exist in the prevalence of LVA EEG variants. In addition, like findings in other populations of non-African descent, having an FH of alcohol dependence may be associated with significantly higher voltage in the alpha frequency ranges.