Lynn A Fairbanks | University of California, Los Angeles (original) (raw)

Papers by Lynn A Fairbanks

The Journal of neuroscience : the official journal of the Society for Neuroscience, 2007

Impulsive behavior and novelty seeking are dimensions of temperament that are behavioral determin... more Impulsive behavior and novelty seeking are dimensions of temperament that are behavioral determinants of risk for attention deficit/hyperactivity disorder and its neurocognitive endophenotypes, and variation in the dopamine D4 receptor gene (DRD4) explains at least a portion of the variance in the traits. To further characterize the dimensional phenotype associated with impulsiveness, adolescent male monkeys were evaluated using ecologically valid tests of impulsive approach and aggression in response to social or nonsocial stimuli; subsequently, a delayed response task was implemented to assess spatial working memory performance. Subjects were selected into this study based on their response to the social challenge task or by DRD4 genotype, resulting in three groups: low-impulsivity/common DRD4 allele, high-impulsivity/common DRD4 allele, or rare DRD4 allele. All animals acquired the delayed response task and could perform at near ceiling levels when a approximately 0 s delay version was imposed, but as delays were lengthened, high-impulsive animals, regardless of DRD4 genotype, made fewer correct responses than did low-impulsive subjects; an inverse relationship existed for working memory and impulsivity. Notably, impulsive behavior evoked by social and nonsocial stimuli explained overlapping and independent portions of the variance in working memory performance. CSF levels of monoamine metabolites did not significantly differentiate the high- and low-impulsive animals, although monkeys carrying the DRD4 rare allele tended to exhibit higher monoamine turnover. These data indicate that dimensions of impulsivity may impact on working memory performance in qualitatively similar ways but through different mechanisms.

The Journal of Clinical Psychiatry, 2000

Human and animal studies point to 3 dimensions of personality that change during pharmacotherapy ... more Human and animal studies point to 3 dimensions of personality that change during pharmacotherapy with a selective serotonin reuptake inhibitor (SSRI). Specifically, harm avoidance has been found to decrease, social dominance has been found to increase, and hostility in social situations has been found to decrease with SSRI treatment. We sought to determine personality changes in subjects with either major depressive disorder (MDD) or obsessive-compulsive disorder (OCD) treated with paroxetine. We also sought to determine whether or not these personality changes were associated with disease state (MDD vs. OCD) or treatment response (responders vs. nonresponders). Thirty-seven subjects diagnosed with either MDD or OCD (according to DSM-IV criteria) completed the Cattell 16 Personality Factor Inventory (16-PF) before and after treatment with paroxetine. Treatment response was defined as a Clinical Global Impressions-Improvement rating of &amp;quot;much&amp;quot; or &amp;quot;very much&amp;quot; improved and a drop in Hamilton Rating Scale for Depression score of at least 50% for MDD or Yale-Brown Obsessive Compulsive Scale score of at least 30% for OCD. No significant differences were found between subjects with MDD and OCD in personality change with treatment. In the whole group, treatment responders had a greater decrease than nonresponders in 16-PF factors relating to harm avoidance. An increase in social dominance factors and a decrease in factors relating to hostility in social situations were found, but these changes were not significantly different between responders and nonresponders. These findings indicate that certain personality dimensions change with SSRI treatment and that some of these changes are independent of clinical treatment response.

Psychiatry Research: Neuroimaging, 1999

Functional brain imaging studies of subjects with Major Depressive Disorder (MDD) have suggested ... more Functional brain imaging studies of subjects with Major Depressive Disorder (MDD) have suggested that decreased dorsolateral (DLPFC) and increased ventrolateral (VLPFC) prefrontal cortical activity mediate the depressed state. Pre- to post-treatment studies indicate that these abnormalities normalize with successful treatment. We performed [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) scans on 16 outpatients with MDD before and after treatment with paroxetine (target dose = 40 mg/day). Regions of interest (ROIs) for this analysis were drawn by a rater blind to subject identity on the magnetic resonance image of each subject and transferred onto their coregistered PET scans. We hypothesized that DLPFC metabolism would increase, while ventral frontal metabolism [in the VLPFC, the orbitofrontal cortex (OFC), and the inferior frontal gyrus (IFG)] would decrease with successful treatment. Treatment response was defined as a decrease in the Hamilton Depression Rating Scale of &amp;gt; 50% and a Clinical Global Improvement Scale rating of &amp;#39;much&amp;#39; or &amp;#39;very much&amp;#39; improved. By these criteria, nine of the subjects were classified as treatment responders. These responders had significantly greater decreases in normalized VLPFC and OFC metabolism than did non-responders. There were no significant effects of treatment response on change in the DLPFC or IFG in this sample. However, there was a positive correlation between change in HAM-D scores and change in normalized IFG and VLPFC metabolism. There were no significant interactions with laterality. On pre-treatment scans, lower metabolism in the left ventral anterior cingulate gyrus was associated with better treatment response. These findings implicate ventral prefrontal-subcortical brain circuitry in the mediation of response to serotonin reuptake inhibitors in MDD.

PLoS ONE, 2011

Asymmetry is a prominent feature of human brains with important functional consequences. Many asy... more Asymmetry is a prominent feature of human brains with important functional consequences. Many asymmetric traits show population bias, but little is known about the genetic and environmental sources contributing to inter-individual variance. Anatomic asymmetry has been observed in Old World monkeys, but the evidence for the direction and extent of asymmetry is equivocal and only one study has estimated the genetic contributions to inter-individual variance. In this study we characterize a range of qualitative and quantitative asymmetry measures in structural brain MRIs acquired from an extended pedigree of Old World vervet monkeys (n = 357), and implement variance component methods to estimate the proportion of trait variance attributable to genetic and environmental sources. Four of six asymmetry measures show pedigree-level bias and one of the traits has a significant heritability estimate of about 30%. We also found that environmental variables more significantly influence the width of the right compared to the left prefrontal lobe.

Obesity, 2007

Characterization and heritability of obesity and associated risk factors in vervet monkeys. Obesi... more Characterization and heritability of obesity and associated risk factors in vervet monkeys. Obesity. 2007;15:1666 -1674. Objective: The objective was to determine the prevalence and heritability of obesity and risk factors associated with metabolic syndrome (MS) in a pedigreed colony of vervet monkeys. Design: A cross-sectional study of plasma lipid and lipoprotein concentrations, glycemic indices, and morphometric measures with heritability calculated from pedigree analysis. A selected population of females was additionally assessed for insulin sensitivity and glucose tolerance. Subjects: All mature male (n ϭ 98), pregnant (n ϭ 40) and non-pregnant female (n ϭ 157) vervet monkeys were included in the study. Seven non-pregnant females were selected on the basis of high or average glycated hemoglobin (GHb) for further characterization of carbohydrate metabolism. Measurements: Morphometric measurements included body weight, length, waist circumference, and calculated BMI. Plasma lipids [total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C)] and glycemic measures (fasting blood glucose, insulin, and GHb) were measured. A homeostasis model assessment index was further reported. Glucose tolerance testing and hyperinsulinemic-euglycemic clamps were performed on 7 selected females. Conclusion: Vervet monkeys demonstrate obesity, insulin resistance, and associated changes in plasma lipids even while consuming a low-fat (chow) diet. Furthermore, these parameters are heritable. Females are at particular risk for central obesity and an unfavorable lipid profile (higher TG, TC, and no estrogen-related increase in HDL-C). Selection of females by elevated GHb indicated impaired glucose tolerance and was associated with central obesity. This colony provides a unique opportunity to study the development of obesity-related disorders, including both genetic and environmental influences, across all life stages.

Neuropsychopharmacology, 2001

Animal and human research suggests that the central serotonin system is involved in the inhibitio... more Animal and human research suggests that the central serotonin system is involved in the inhibition of impulsive behavior. Two studies were designed to assess this relationship in male vervet monkeys ( Cercopithecus aethiops sabaeus ) using a standardized test of impulsivity in a social context: the Intruder Challenge. In the first study, an index of impulsivity in response to an unfamiliar adult male intruder (including latency to approach and aggressive and assertive interactions) was inversely correlated with levels of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA) in cisternal cerebrospinal fluid (r ϭ Ϫ 0.33, p Ͻ .01, n ϭ 138). The approach, but not aggressive, component of the Impulsivity Index was the primary contributor to this relationship (partial r ϭ Ϫ 0.27, p Ͻ .01). The second experiment compared responses to the Intruder Challenge after 9 weeks of daily treatment with fluoxetine (2 mg/kg, i.m.) or vehicle. Fluoxetine-treated subjects ( n ϭ 6) had significantly lower Impulsivity Index scores than controls ( n ϭ 12). The results from these two investigations provide evidence for serotonergic influences on social impulsivity.

NeuroImage, 2011

Vervet monkeys are a frequently studied animal model in neuroscience research. Although equally d... more Vervet monkeys are a frequently studied animal model in neuroscience research. Although equally distantly related to humans, the ancestors of vervets diverged from those of macaques and baboons more than eleven million years ago, antedating the divergence of the ancestors of humans, chimpanzees and gorillas. To facilitate anatomic localization in the vervet brain, two linked online electronic atlases are described, one based on registered MRI scans from hundreds of vervets (http://www.loni.ucla.edu/Research/Atlases/Data/vervet/vervetmratlas/vervetmratlas.html) and the other based on a high-resolution cryomacrotome study of a single vervet (http://www.loni.ucla.edu/Research/Atlases/Data/vervet/vervetatlas/vervetatlas.html). The averaged MRI atlas is also available as a volume in Neuroimaging Informatics Technology Initiative format. In the cryomacrotome atlas, various sulcal and subcortical structures have been anatomically labeled and surface rendered views are provided along the primary planes of section. Both atlases simultaneously provide views in all three primary planes of section, rapid navigation by clicking on the displayed images, and stereotaxic coordinates in the averaged MRI atlas space.

Magnetic Resonance in Medicine, 2002

The test-retest reliability of two-dimensional (2D) correlated spectroscopy (COSY) was studied on... more The test-retest reliability of two-dimensional (2D) correlated spectroscopy (COSY) was studied on a whole-body 1.5T MRI scanner. Single-voxel localized 2D proton spectra were recorded in vitro as well as in vivo using a recently implemented localized chemical shift correlated spectroscopic (L-COSY) sequence. A total of 40 in vitro and 40 human brain (10 volunteers, four times each) 2D L-COSY spectra were recorded. The coefficients of variation (CVs) of selected brain metabolites (raw volume integrals) recorded in 10 healthy volunteers were less than 9% for creatine, choline, and N-acetyl aspartate, and less than 17% for myo-inositol, glutamine/glutamate, aspartate, and threonine/lactate. The 2D metabolite ratios and the raw volume integrals of 2D diagonal and cross peaks in healthy human brain were very well reproduced. The intraclass correlation coefficients were greater than 0.4 (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.05) for the major metabolites, indicating that the 2D peak volumes were stable enough within individuals to detect reliable differences between normal subjects.

Journal of the International Neuropsychological Society, 2002

Apathy is a common behavioral disturbance in patients with Alzheimer&amp;amp;amp;amp;amp;... more Apathy is a common behavioral disturbance in patients with Alzheimer&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease (AD). Recent studies have linked the presence of apathy to alterations in frontal lobe functions, but few studies have explored the relationship using standard neuropsychological measures in patients with AD. We administered a comprehensive battery of neuropsychological tests and a behavior rating scale to 80 patients with AD. We explored the relationship of apathy to executive dysfunction. AD patients with apathy performed significantly worse on tests of executive function (WAIS-R Digit Symbol, Trail-Making, Stroop Color Interference Test) than AD patients without apathy. The presence of dysphoria did not modify these results and no significant relationships were found between tests of executive functions and dysphoria. Performance on executive measures as a group were effective in correctly classifying patients as apathetic or nonapathetic with 75% accuracy. Neuropsychological measures not dependent on executive functions were unrelated to apathy. Apathy is associated with executive dysfunction and not with other neuropsychological deficits. Apathy is distinct from dysphoria.

Journal of the American Academy of Child & Adolescent Psychiatry, 1999

To compare moral development and psychopathological interference with conscience functioning (PI)... more To compare moral development and psychopathological interference with conscience functioning (PI) among adolescents exposed to different degrees of earthquakerelated trauma and to investigate the relationship of moral development and PI to exposure to trauma, severity of posttraumatic stress disorder (PTSD) symptoms, postearthquake adversities, and extent of loss of nuclear family members. Method: Adolescents (N = 193) from 2 cities at different distances from the epicenter were evaluated. The Stilwell Structured Conscience Interview was used to assess moral development and PI. Structured self-report instruments were used to obtain ratings of severity of earthquake-related trauma, posttraumatic stress symptoms, and postearthquake adversities. Results: Adolescents in the city near the epicenter manifested advanced moral development as compared with their counterparts in the less affected city. Concomitantly, they endorsed responses indicating PI. Levels of PI were significantly correlated with severity of PTSD symptoms. Conclusion: In the aftermath of a catastrophic natural disaster, children assume greater responsibilities and confront a multitude of morally challenging interpersonal situations which may result in an advancement of their moral development. Yet, at the same time, PTSD symptoms and negative schematizations of self and others may give rise to disturbances in conscience functioning. The findings suggest that therapeutic consideration should be given to assisting children in integrating the horror of their traumatic experiences and the harshness of posttrauma adversities into an adaptive schema of good and evil in themselves and the world. J. Am. Acad. Child Adolesc. Psychiatry, 1999, 38(4):376-384. Key Words: moral development, trauma, posttraumatic stress disorder.

The Journal of Nervous and Mental Disease, 1979

The revelance of sociobiology to psychiatry is examined through a consideration of the theories o... more The revelance of sociobiology to psychiatry is examined through a consideration of the theories of kin selection and reciprocal altruism. Predictions developed from these theories are compared with currently available mental-health statistics. The theory of kin selection is used to predict a positive correlation between mental health and the existence of an active kin-support system. Similarly, the theory of reciprocal altruism is used to predict a positive correlation between mental health and the existence of an active friend-support system. The findings tend to support both sets of predictions in that individuals with access to kin-support and/or friend-support systems are less likely to be hospitalized with psychiatric disorders than are individuals without access to such systems. Sociobiology may be useful to psychiatry in that in some cases it provides: a) a new focus on the adaptive functions of human behavior which may serve to aid the psychiatrist in evaluating individual problems; b) functional predictions which may help to identify segments of the population which are more at risk for psychiatric disorders than others, thereby providing guidelines for preventive psychiatry; and c) direction for research into unexplored aspects of human social relationships and their relevance to psychiatric disorders.

Journal of Medical Primatology, 2011

Background Causes of infant death remain unknown in significant proportions of human and non-huma... more Background Causes of infant death remain unknown in significant proportions of human and non-human primate pregnancies. Methods A closed breeding colony with high rates of infant mortality had pregnancies assessed (n = 153) by fetal measurements and maternal characteristics. Infant outcome was classified as neonatal death (stillborn or died <48 hours from birth), postnatal death (died 2-30 days) or surviving (alive after 30 days). Results Fetal size did not predict outcome. Poor maternal glycemic control and low social ranking increased odds for adverse outcome (OR = 3.72, P = 0.01 and 2.27, P = 0.04, respectively). Male sex was over-represented in stillbirths (P = 0.04), and many were macrosomic, but size did not associate with maternal glycemic control measured as glycated hemoglobin A1c. Postnatally dead infants were smaller (P < 0.01), which associated with behavioral factors and glycemic control. Conclusions Fetal growth estimates predicted gestational age but not fetal outcome. Maternal social status and metabolic health, particularly glycemic control, increased risks of adverse pregnancy outcome.

Journal of Comparative Psychology, 2001

Social impulsivity in response to a stranger was assessed in male vervet monkeys (Cercopithecus a... more Social impulsivity in response to a stranger was assessed in male vervet monkeys (Cercopithecus aethiops sabaeus) using the Intruder Challenge Test. Vervets (N = 128, ages 3-18 years) were presented with an unfamiliar adult male at the periphery of the home enclosure. An index of impulsivity reflecting variation in the tendency to rapidly approach, engage, and challenge the intruder was derived from factor analysis of behavioral responses. Scale reliability (alpha = .84) and test-retest consistency (intraclass correlation = .83) were high, indicating that this index reliably and efficiently measures a stable aspect of temperament from impulsive to inhibited. Impulsivity scores peaked at age 4, when vervet males typically emigrate from the natal group. The highest ranking males in each group were more likely to score in the moderate range, whereas lower ranking males were more likely to score in the highest (impulsive) or lowest (inhibited) quartiles.

Journal of Abnormal Psychology, 1982

Videotaped interviews of 50 psychiatric inpatients and 25 control Ss with 5 psychiatrists and ana... more Videotaped interviews of 50 psychiatric inpatients and 25 control Ss with 5 psychiatrists and analyzed the nonverbal behavior, which was coded and recorded every 10 sec for 2 5-min segments per interview. After the interview the therapists rated the Ss on the Brief Psychiatric Rating Scale (BPRS). Results show that the psychiatric patients held their legs symmetrically, groomed themselves, shifted

International Journal of Primatology, 1984

Sixty-one instances of vertebrate predation have been directly observed or inferred from remains ... more Sixty-one instances of vertebrate predation have been directly observed or inferred from remains in a captive colony of vervet monkeys (Cercopithecus aethiops sabaeus)over a 6-year period. Vertebrate prey included 33 rodents,27 birds, and 1 frog. Prey capturing was performed predominantly by juvenile males and females, independent of rank. Avian prey were highly preferred: all 27 birds were eaten completely, while

Journal of traumatic stress, 2003

This study evaluated basal levels and responsiveness to exercise of plasma adrenocorticotropic ho... more This study evaluated basal levels and responsiveness to exercise of plasma adrenocorticotropic hormone (ACTH), and serum thyroid stimulating hormone (TSH), growth hormone (GH) and cortisol among adolescents from two differentially exposed groups 6 1/2 years after the 1988 earthquake in Armenia. Severity of total PTSD and Category C and D symptoms were negatively correlated with baseline cortisol. Preexercise ACTH was significantly lower, and preexercise TSH higher, among adolescents with more exposure. Depressive symptoms were negatively correlated with baseline cortisol and positively with TSH. Mean GH, TSH, and cortisol levels in both groups fell within normal limits. The pre- to postexercise increase in GH, TSH, and cortisol suggests that exercise challenge may be useful in the field investigation of neurohormonal activity among traumatized individuals.

Biological Psychiatry, 1999

Biological Psychiatry, 2001

Symptoms of major depressive disorder (MDD) have been linked to regional brain function through i... more Symptoms of major depressive disorder (MDD) have been linked to regional brain function through imaging studies of symptom provocation in normal control subjects and baseline studies of subjects with MDD. We examined associations between change in depressive symptom factors and change in regional brain metabolism from before to after treatment of MDD. Thirty-nine outpatients with MDD underwent 18F-fluorodeoxyglucose positron emission tomography scanning before and after treatment with either paroxetine or interpersonal psychotherapy. Associations were determined between changes in regional brain metabolism and changes in four Hamilton Depression Rating Scale factors (anxiety/somatization [ANX], psychomotor retardation [PR], cognitive disturbance [COGN], and sleep disturbance) and two corresponding Profile of Mood States subscales (tension [TENS] and fatigue [FATIG]). Improvement in ANX, PR, TENS, and FATIG factors was associated with decreasing ventral frontal lobe metabolism. Improvement in ANX and TENS was also associated with decreasing ventral anterior cingulate gyrus (AC) and anterior insula activity, whereas improvement in PR was associated with increasing dorsal AC activity. COGN improvement was associated with increasing dorsolateral prefrontal cortex metabolism. Brain regions that show significant relationships with symptom provocation in normal control subjects have similar relationships with MDD symptoms as they improve with treatment.