Science posts

See science posts on page 18 below.

    • 2014
    • Bianca P. Acevedo et al.
    • The highly sensitive brain: an fMRI study of sensory processing sensitivity and response to others' emotions
    • Background Theory and research suggest that sensory processing sensitivity (SPS), found in roughly 20% of humans and over 100 other species, is a trait associated with greater sensitivity and responsiveness to the environment and to social stimuli. Self-report studies have shown that high-SPS individuals are strongly affected by others' moods, but no previous study has examined neural systems engaged in response to others' emotions. Methods This study examined the neural correlates of SPS (measured by the standard short-form Highly Sensitive Person [HSP] scale) among 18 participants (10 females) while viewing photos of their romantic partners and of strangers displaying positive, negative, or neutral facial expressions. One year apart, 13 of the 18 participants were scanned twice. Results Across all conditions, HSP scores were associated with increased brain activation of regions involved in attention and action planning (in the cingulate and premotor area [PMA]). For happ..
    • 2006
    • Emily M. Drabant et al.
    • Catechol O-methyltransferase Val158Met Genotype and Neural Mechanisms Related to Affective Arousal and Regulation
    • Context Catechol O-methyltransferase (COMT), the major enzyme determining cortical dopamine flux, has a common functional polymorphism (val158met) that affects prefrontal function and working memory capacity and has also been associated with anxiety and emotional dysregulation. Objectives To examine COMT val158met effects on corticolimbic circuitry reactivity and functional connectivity during processing of biologically salient stimuli, as well as the relationship to the temperamental trait of novelty seeking. Design Within-subject functional magnetic resonance imaging study. Setting National Institute of Mental Health, Genes, Cognition, and Psychosis Program, Bethesda, Md. Patients One hundred one healthy subjects of both sexes. Results We found that the met allele was associated with a dose-dependent increase in hippocampal formation and ventrolateral prefrontal cortex activation during viewing of faces displaying negative emotion. In met/met homozygotes, lim..
    • 2003
    • Enoch, Mary-Anne et al.
    • Genetic origins of anxiety in women: a role for a functional catechol-O-methyltransferase polymorphism
    • Objective: Women are more prone to anxiety than men. The catechol-O-methyltransferase functional polymorphism, Val158Met, is likely to be implicated in anxiety vulnerability. We hypothesized that, particularly in women, the low-activity Met158 allele would be associated with higher anxiety scores and a biological trait, low-voltage alpha resting electroencephalogram (EEG), previously associated with alcoholism and anxiety disorders. Methods: DNA was obtained from two independent groups of participants ascertained as community samples: 149 predominantly Caucasian individuals (92 women, 57 men), and 252 Plains American Indians (149 women, 103 men). Dimensional measures of anxiety (Tridimensional Personality Questionnaire harm avoidance subscales HA1 and HA2) were obtained and DSM-III-R lifetime psychiatric diagnoses were determined. EEGs were recorded and EEG phenotypes assigned. Result: In both populations, women showed significant associations between catechol-O-methyltransfe..
    • 2004
    • Tsai S.-J. et al.
    • Association Study of Catechol- O-Methyltransferase Gene and Dopamine D4 Receptor Gene Polymorphisms and Personality Traits in Healthy Young Chinese Females
    • Human personality traits, which are substantially heritable, may be modulated by monoamine neurotransmitters. It has been demonstrated that the catechol-O-methyltransferase (COMT) Val158Met genetic polymorphism, a functional polymorphism that may affect monoamine metabolism, is possibly associated with specific personality traits. In addition, a polymorphism in the dopamine D4 receptor (DRD4) gene exon 3 has been associated in some, but not all, studies with the novelty seeking personality trait, as evaluated by the Tridimensional Personality Questionnaire (TPQ). In this study, associations between these two polymorphisms and TPQ personality traits were investigated in a sample population of 120 healthy young Chinese females. The results of this analysis reveal that the COMT Val158Met polymorphism was significantly associated with novelty seeking (p = 0.017) and reward dependence scores (p = 0.015) in our sample. However, no significant differences were demonstrated comparing TPQ-spe..
    • 2004
    • Jingshan Chen et al.
    • Functional Analysis of Genetic Variation in Catechol-O-Methyltransferase (COMT): Effects on mRNA, Protein, and Enzyme Activity in Postmortem Human Brain
    • Catechol-O-methyltransferase (COMT) is a key enzyme in the elimination of dopamine in the prefrontal cortex of the human brain. Genetic variation in the COMT gene (MIM 116790) has been associated with altered prefrontal cortex function and higher risk for schizophrenia, but the specific alleles and their functional implications have been controversial. We analyzed the effects of several single-nucleotide polymorphisms (SNPs) within COMT on mRNA expression levels (using reverse-transcriptase polymerase chain reaction analysis), protein levels (using Western blot analysis), and enzyme activity (using catechol methylation) in a large sample (n = 108) of postmortem human prefrontal cortex tissue, which predominantly expresses the -membrane-bound isoform. A common coding SNP, Val158Met (rs4680), significantly affected protein abundance and enzyme activity but not mRNA expression levels, suggesting that differences in protein integrity account for the difference in enzyme activity between ..
    • 1996
    • Lachman, Herbert M. et al.
    • Human catechol-O-methyltransferase pharmacogenetics: description of a functional polymorphism and its potential application to neuropsychiatric disorders.
    • Catechol-O-methyltransferase (COMT) inactivates catecholamines and catechol drugs such as L-DOPA. A common genetic polymorphism in humans is associated with a three-to-fourfold variation in COMT enzyme activity and is also associated with individual variation in COMT thermal instability. We now show that this is due to G-[right pointing guillemet]A transition at codon 158 of the COMT gene that results in a valine to methionine substitution. The two alleles can be identified with a PCR-based restriction fragment length polymorphism analysis using the restriction enzyme Ma III. The identification of a gentic marker associated with significant alterations in enzyme activity will facilitate the analysis of a possible role for the COMT gene in neuropsychiatric conditions in which abnormalities in catecholamine neurotransmission are believed to occur, including mood disorders, schizophrenia, obsessive compulsive disorder, alcohol and substance abuse, and attention deficit hyperactivity dis..
    • 2008
    • Jean-Claude Dreher et al.
    • Variation in dopamine genes influences responsivity of the human reward system
    • In humans, dopamine neurotransmission is influenced by functional polymorphisms in the dopamine transporter (DAT1) and catechol-O-methyltransferase (COMT) genes. Here, we used event-related functional magnetic resonance imaging to directly investigate the neurofunctional effects of the Val158Met COMT and variable number of tandem repeat DAT1 polymorphisms on distinct components of the reward system in humans. The results revealed a main effect of COMT genotype in the ventral striatum and lateral prefrontal cortex during reward anticipation (P < 0.001, uncorrected) and in the orbitofrontal cortex at the time of reward delivery (P < 0.005), met/met individuals exhibiting the highest activation. The main effect of DAT1 genotype was seen in robust blood-oxygen-level-dependent response differences in the caudate nucleus and ventral striatum during reward anticipation (P < 0.001) and in the lateral prefrontal cortex and midbrain at the time of reward delivery, with carriers of the..
    • 2009
    • Tim Hahn et al.
    • Neural response to reward anticipation is modulated by Gray's impulsivity
    • According to the Reinforcement Sensitivity Theory (RST), Gray’s dimension of impulsivity, reflecting human trait reward sensitivity, determines the extent to which stimuli activate the Behavioural Approach System (BAS). The potential neural underpinnings of the BAS, however, remain poorly understood. In the present study, we examined the association between Gray’s impulsivity as defined by the RST and event-related fMRI BOLD-response to anticipation of reward in twenty healthy human subjects in brain regions previously associated with reward processing. Anticipation of reward during a Monetary Incentive Delay Task elicited activation in key components of the human reward circuitry such as the ventral striatum, the amygdala and the orbitofrontal cortex. Interindividual differences in Gray’s impulsivity accounted for a significant amount of variance of the reward-related BOLD-response in the ventral striatum and the orbitofrontal cortex. Specifically, higher trait rew..
    • 2005
    • Paul J Kenny et al.
    • Nicotine Self-Administration Acutely Activates Brain Reward Systems and Induces a Long-Lasting Increase in Reward Sensitivity
    • Nicotine is a major component of tobacco smoke contributing to the initiation and persistence of the harmful tobacco habit in human smokers. The reinforcing effects of nicotine likely arise through its ability to stimulate brain circuitry mediating the detection and experiencing of natural rewards. Nevertheless, remarkably little is known concerning the acute or long-lasting actions of nicotine on brain reward systems in vivo. Here, we investigated the effects of intravenously self-administered nicotine (0.03 mg/kg/infusion, free base) on the sensitivity of brain reward systems, reflected in alterations of intracranial self-stimulation (ICSS) thresholds in rats. Rats self-administered nicotine during 1 or 12 h daily sessions, with reward thresholds assessed 1 h before and 15 min after each self-administration session. Control rats remained nicotine naïve throughout. Nicotine self-administration increased the sensitivity of brain reward systems, detected by post-nicotine lowering..
    • 2015
    • Helen Uusberg et al.
    • Eye contact reveals a relationship between Neuroticism and anterior EEG asymmetry
    • Although anterior functional brain asymmetry has been linked to individual differences in affect and motivation, its relations with the Five Factor Model personality traits remain unclear. We investigated anterior EEG alpha-activity asymmetry in response to variable degrees of social contact induced by different gaze directions of a “live” model. Neuroticism was negatively related to the anterior EEG asymmetry scores in response to direct gaze, indicating that higher levels of Neuroticism were associated with avoidance-related, relative right-sided functional brain asymmetry. Neuroticism was also related to behavioral direct gaze avoidance and subjective averted gaze preference. These relationships arose primarily from the Withdrawal aspect factor, suggesting that two subdomains of Neuroticism may be differentially related to approach-avoidance tendencies. These findings demonstrate that experimental manipulations of social contact can reveal personality related differenc..

Related

You might be interested in.