Brain imaging, genetics and emotion

Fear of the unknown as a mechanism of the inverse relation between life meaning and psychological distress

BACKGROUND AND OBJECTIVES

Although there is accumulating evidence for an inverse relation between life meaning and psychological distress, little is known about the mechanisms of this relation. Using cross-sectional, observational methods, this research examined fear of uncertainty as one potential mechanism.

DESIGN AND METHODS

Study 1 (N = 141) was completed with a convenience sample, a unidimensional measure of life meaning, and general measures of anxiety and depression. Study 2 (N = 152) was completed with a sample prescreened for anxiety, a multidimensional measure of life meaning, and clinical measures of anxiety and depression.

RESULTS

The results from both studies generally showed an inverse relation between life meaning and psychological distress. Study 2 further indicated that these relations were stronger for the meaning subscale of perceiving life as coherent/comprehensible than the subscales assessing whether participants' lives are perceived as purposeful or significant. Mediation analyses in both studies showed indirect effects of life meaning on psychological distress through fear of uncertainty.

CONCLUSIONS

These findings support and extend previous research by showing that (i) meaning-as-comprehension may be particularly important in regards to psychological distress, and (ii) fear of uncertainty may mediate the inverse relation between meaning and measures of anxiety and depression.

Individual Differences in the Speed of Facial Emotion Recognition Show Little Specificity but Are Strongly Related with General Mental Speed: Psychometric, Neural and Genetic Evidence

Facial identity and facial expression processing are crucial socio-emotional abilities but seem to show only limited psychometric uniqueness when the processing speed is considered in easy tasks. We applied a comprehensive measurement of processing speed and contrasted performance specificity in socio-emotional, social and non-social stimuli from an individual differences perspective. Performance in a multivariate task battery could be best modeled by a general speed factor and a first-order factor capturing some specific variance due to processing emotional facial expressions. We further tested equivalence of the relationships between speed factors and polymorphisms of dopamine and serotonin transporter genes. Results show that the speed factors are not only psychometrically equivalent but invariant in their relation with the Catechol-O-Methyl-Transferase (COMT) Val158Met polymorphism. However, the 5-HTTLPR/rs25531 serotonin polymorphism was related with the first-order factor of emotion perception speed, suggesting a specific genetic correlate of processing emotions. We further investigated the relationship between several components of event-related brain potentials with psychometric abilities, and tested emotion specific individual differences at the neurophysiological level. Results revealed swifter emotion perception abilities to go along with larger amplitudes of the P100 and the Early Posterior Negativity (EPN), when emotion processing was modeled on its own. However, after partialling out the shared variance of emotion perception speed with general processing speed-related abilities, brain-behavior relationships did not remain specific for emotion. Together, the present results suggest that speed abilities are strongly interrelated but show some specificity for emotion processing speed at the psychometric level. At both genetic and neurophysiological levels, emotion specificity depended on whether general cognition is taken into account or not. These findings keenly suggest that general speed abilities should be taken into account when the study of emotion recognition abilities is targeted in its specificity.

Hypothesizing Music Intervention Enhances Brain Functional Connectivity Involving Dopaminergic Recruitment: Common Neuro-correlates to Abusable Drugs

The goal of this review is to explore the clinical significance of music listening on neuroplasticity and dopaminergic activation by understanding the role of music therapy in addictive behavior treatment. fMRI data has shown that music listening intensely modifies mesolimbic structural changes responsible for reward processing (e.g., nucleus accumbens [NAc]) and may control the emotional stimuli's effect on autonomic and physiological responses (e.g., hypothalamus). Music listening has been proven to induce the endorphinergic response blocked by naloxone, a common opioid antagonist. NAc opioid transmission is linked to the ventral tegmental area (VTA) dopamine release. There are remarkable commonalities between listening to music and the effect of drugs on mesolimbic dopaminergic activation. It has been found that musical training before the age of 7 results in changes in white-matter connectivity, protecting carriers with low dopaminergic function (DRD2A1 allele, etc.) from poor decision-making, reward dependence, and impulsivity. In this article, we briefly review a few studies on the neurochemical effects of music and propose that these findings are relevant to the positive clinical findings observed in the literature. We hypothesize that music intervention enhances brain white matter plasticity through dopaminergic recruitment and that more research is needed to explore the efficacy of these therapies.

Association between the Catechol-O-Methyltransferase (COMT) Val¹⁵⁸Met Polymorphism and Alexithymia in Patients with Obsessive-Compulsive Disorder

PURPOSE

Alexithymia, defined as a deficit in the ability to recognize and describe one's own feelings, may be related to the development and maintenance of obsessive-compulsive symptoms. The aim of this study was to evaluate the association between the catechol-O-methyltransferase (COMT) Val¹⁵⁸Met polymorphism and alexithymia in patients with obsessive-compulsive disorder (OCD).

MATERIALS AND METHODS

We recruited 244 patients with OCD (169 males, 75 females). Alexithymia was assessed using the 20-item Toronto Alexithymia Scale (TAS-20), and genotyping of the COMT Val¹⁵⁸Met polymorphism was evaluated.

RESULTS

Patients with the COMT Val/Val genotype had significantly higher total and "difficulty identifying feelings" (DIF) subdimension scores than those with the Val/Met or Met/Met genotypes. Patients with the COMT Val/Val genotype had significantly higher "difficulty describing feelings" (DDF) subdimension scores than those with the COMT Val/Met genotype. However, there were no differences in the scores for the "externally oriented thinking" (EOT) subdimension among the three genotypes.

CONCLUSION

These results indicate that the high-activity Val allele of the COMT Val¹⁵⁸Met polymorphism is associated with increased alexithymic traits in patients with OCD. The present finding suggests that alexithymia is an endophenotype of OCD that is mediated by the COMT Val¹⁵⁸Met polymorphism.

Supraphysiological hormonal status, anxiety disorders, and COMT Val/Val genotype are associated with reduced sensorimotor gating in women

Pregnancy is a period characterized by a supraphysiological hormonal status, and greater anxiety proneness, which can lead to peripartum affective symptoms with dramatic consequences not only for the woman but also for the child. Clinical psychiatry is heavily hampered by the paucity of objective and biology-based intermediate phenotypes. Prepulse inhibition (PPI) of the startle response, a neurophysiological measure of sensorimotor gating, has been poorly investigated in relation to anxiety and in pregnant women. In the present study, the PPI of healthy non-pregnant women (n = 82) and late pregnant women (n = 217) was investigated. Age, BMI, depression and anxiety symptoms, tobacco use, and antidepressant medication were considered. We investigated and provided evidence of lower PPI: (i) in healthy pregnant women compared to healthy non-pregnant controls, (ii) in pregnant women with anxiety disorders compared to healthy pregnant women, (iii) in pregnant women with anxiety disorders using SSRI compared to un-medicated pregnant women with anxiety disorders, and (iv) in healthy pregnant women carrying the COMT Val158Met Val/Val genotype compared to Met carriers. Altogether, a reduced sensorimotor gating as an effect of supraphysiological hormonal status, anxiety disorders, SSRIs, and catecholaminergic genotype, implicate the putative relevance of lower PPI as an objective biological correlate of anxiety proneness in pregnant women. These findings call for prospective studies to dissect the multifactorial influences on PPI in relation to mental health of pregnant women.

A 9-nucleotide Ins/Del in ADRA2B modulates orientation of attention to facial expressions and emotional words

Norepinephrine is involved in the arousal of attention and the treatment of affective disorders. Therefore, we hypothesized that adrenergic receptors underpinned individual differences in attention regulation and emotional processes of healthy populations. Here, we investigated to what extent the expression of ADRA2B, an adrenergic receptor, modulated attention regulation and emotional processes. We evaluated orientation of attention, emotion regulation, and pleasantness ratings of expressions and words in 665 college students, and then genotyped the +901 Ins/Del variants in ADRA2B of these participants. The results indicated that +901 Ins/Del significantly modulated orientation of attention to facial expressions and emotional words, such that the Del allele facilitated reorientation to the originally attended locations. However, this polymorphism exerted no significant effects on emotional regulation of attention and pleasantness ratings of emotional stimulus. These findings suggest that ADRA2B is closely related to the individual difference in human attention orientation, but not to the individual difference in emotional processing.

Mouse model systems to study sex chromosome genes and behavior: relevance to humans

Sex chromosome genes directly influence sex differences in behavior. The discovery of the Sry gene on the Y chromosome (Gubbay et al., 1990; Koopman et al., 1990) substantiated the sex chromosome mechanistic link to sex differences. Moreover, the pronounced connection between X chromosome gene mutations and mental illness produces a strong sex bias in these diseases. Yet, the dominant explanation for sex differences continues to be the gonadal hormones. Here we review progress made on behavioral differences in mouse models that uncouple sex chromosome complement from gonadal sex. We conclude that many social and cognitive behaviors are modified by sex chromosome complement, and discuss the implications for human research. Future directions need to include identification of the genes involved and interactions with these genes and gonadal hormones.

Influence of catechol-O-methyltransferase Val158Met polymorphism on startle response in the presence of high estradiol levels

INTRODUCTION

both human and animal studies have shown a somewhat complex COMT-by-sex interaction effect on brain function and dysfunction. A functional variation in the gene coding for the catechol-O-methyltransferase (COMT) enzyme, which metabolizes dopamine and noradrenaline, has been related to executive and emotional functions, and to sex dimorphism.

AIM

to investigate if COMT Val158Met genotype influences startle response in pregnant women, given their physiologically elevated estradiol levels.

METHODS

seventy-three pregnant women were assessed in gestational week 38 for acoustic startle response, measured by electromyography of the blink reflex, during control condition, positive and negative anticipation stimuli, and pleasant and unpleasant image stimuli. A blood sample was taken for measurement of estradiol levels and genetic analysis.

RESULTS

the results indicated a COMT Val158Met effect on startle response across all conditions (main effect of genotype, F(2,70=3.58), p=0.033), where Val/Val women displayed higher startle magnitudes than Val/Met carriers (Cohen's d=0.71). No significant difference by genotype was found in affective modulation. The findings also suggested an estrogen dose-dependent effect of COMT Val158Met on startle reflex. Among women with higher pregnancy-induced estradiol levels, Val/Val carriers had markedly higher startle response across conditions than heterozygotes (Cohen's d=1.36; F(4,21=11.07); p=0.003), while this effect was not present in women with estradiol levels under the median concentration.

CONCLUSIONS

the observed effect of COMT Val158Met by estradiol on overall startle response is likely to be due to a variable noradrenergic transmission depending on COMT activity in a possible interaction with estradiol.

On the genetic basis of face cognition and its relation to fluid cognitive abilities

The oxytocin and the dopaminergic systems have turned out to be highly relevant for social abilities and cognition. Therefore, we examined the association between two functional gene polymorphisms and face cognition (FC) in a multivariate study (N = 250) by applying structural equation modeling. The catechol-O-methyltransferase (COMT) val158met polymorphism influences the enzyme activity of COMT, which affects the prefrontal dopamine concentration. The rs226849 is a single-nucleotide polymorphism located in the promoter region of the oxytocin receptor (OXTR) gene, modulating the mRNA expression. By modeling a general fluid ability factor (defined by working memory and reasoning) and nested FC factors, we tested genetic contributions to FC, after controlling for variance in FC that was also associated with fluid abilities. In line with several previous studies, we found a significant association between the COMT genotype and fluid abilities (Gf) but not with FC. The association between the oxytocin polymorphism and Gf was opposite in direction for men and women. Women with the C(+) genotype performed better on Gf tasks than those with the C(-) genotype. Conversely, men with the C(-) genotype performed better than those with the C(+) genotype. There was no significant association between OXTR and the nested FC factor. Therefore, the relationship between the oxytocin polymorphism and FC can be fully accounted for by Gf. The sex specificity of this relationship is a novel finding and warrants a mechanistic explanation.

Deconstructing the familiality of variability in momentary negative and positive affect

OBJECTIVE

The daily life, affective phenotypes of momentary negative affect (NA), positive affect (PA) variability and NA variability are associated with future depressive symptomatology. This study investigates the extent to which genetic and environmental factors contribute to the inter-individual differences in these daily life, affective phenotypes.

METHOD

Two hundred and seventy-nine female twins from the Flemish (Belgium) general population participated in an experience sampling study measuring affect in daily life. Structural equation modelling was used to fit univariate and bivariate models.

RESULTS

Genetic factors explained, respectively, 18%, 18% and 35% of the inter-individual differences in momentary NA, PA variability and NA variability. Non-shared environmental factors were found to explain the remaining inter-individual variation. In addition, 41% of the association between positive and NA variability was attributed to shared genetic factors.

CONCLUSION

Results of this study show that daily life patterns of affective expression are subject to substantial environmental influence. Prospective assessments of the effect of interventions on these expressions may therefore represent a powerful tool to prevent transition from subclinical depressive symptomatology to a clinical outcome or to reduce symptomatology in those with clinical depression.

DRD2 polymorphisms modulate reward and emotion processing, dopamine neurotransmission and openness to experience

Dopamine (DA) neurotransmission through D2 receptors (DRD2) has been implicated in the regulation of reward processing, cognition and the effects of drugs of abuse, and also has significant effects in responses to stressors and salient aversive stimuli. An examination of the influence of genetic variation across multiple psychophysical measures therefore appears critical to understand the neurobiology of DA-modulated complex personality traits and psychiatric illnesses. To examine inter-individual variation in the function of DRD2 modulated mechanisms in healthy humans, we used a haplotype-based and single nucleotide polymorphism (SNP) investigation. Their effects were interrogated with functional magnetic resonance imaging during reward and emotional processing. We found that a haplotype block composed by two SNPs, rs4274224 and rs4581480, affected the hemodynamic responses of the dorsolateral prefrontal cortex (DLPFC) during reward expectation and the subgenual anterior cingulate cortices (sgACC) during implicit emotional processing. Exploratory analysis within the significant haplotype block revealed the same functional effects only for the SNP rs4274224. Further analysis on rs4274224 using functional connectivity and positron emission tomography (PET) measures of DA D2/3 receptor mediated neurotransmission confirmed a gene effect on the functional connectivity of the DLPFC during reward anticipation and subcortical stress induced DA release. At a phenotypic trait level, significant effects of genotype were obtained for the NEO PI-R "Openness to Experience" and further correlated with neuroimaging data. Overall, these results show significant neurobiological effects of genotype variation in DRD2 on multiple functional domains, such as emotional, stress and reward processing. As such, it contributes to normal variation and potentially to vulnerability to psychopathology associated with those functions, such as risk for mood and substance use disorders.

COMT Val158Met genotype influences neurodegeneration within dopamine-innervated brain structures

OBJECTIVE

We sought to determine whether the Val(158)Met polymorphism in the catechol-O-methyltransferase (COMT) gene influences neurodegeneration within dopamine-innervated brain regions.

METHODS

A total of 252 subjects, including healthy controls and patients with Alzheimer disease, behavioral variant frontotemporal dementia, and semantic dementia, underwent COMT genotyping and structural MRI.

RESULTS

Whole-brain voxel-wise regression analyses revealed that COMT Val(158)Met Val allele dosage, known to produce a dose-dependent decrease in synaptic dopamine (DA) availability, correlated with decreased gray matter in the region of the ventral tegmental area (VTA), ventromedial prefrontal cortex, bilateral dorsal midinsula, left dorsolateral prefrontal cortex, and right ventral striatum. Unexpectedly, patients carrying a Met allele showed greater VTA volumes than age-matched controls. Gray matter intensities within COMT-related brain regions correlated with cognitive and behavioral deficits.

CONCLUSIONS

The results are consistent with the hypothesis that increased synaptic DA catabolism promotes neurodegeneration within DA-innervated brain regions.

The role of the amygdala in face perception and evaluation

Faces are one of the most significant social stimuli and the processes underlying face perception are at the intersection of cognition, affect, and motivation. Vision scientists have had a tremendous success of mapping the regions for perceptual analysis of faces in posterior cortex. Based on evidence from (a) single unit recording studies in monkeys and humans; (b) human functional localizer studies; and (c) meta-analyses of neuroimaging studies, I argue that faces automatically evoke responses not only in these regions but also in the amygdala. I also argue that (a) a key property of faces represented in the amygdala is their typicality; and (b) one of the functions of the amygdala is to bias attention to atypical faces, which are associated with higher uncertainty. This framework is consistent with a number of other amygdala findings not involving faces, suggesting a general account for the role of the amygdala in perception.

Variation of the gene coding for DARPP-32 (PPP1R1B) and brain connectivity during associative emotional learning

Associative emotional learning, which is important for the social emotional functioning of individuals and is often impaired in psychiatric illnesses, is in part mediated by dopamine and glutamate pathways in the brain. The protein DARPP-32 is involved in the regulation of dopaminergic and glutaminergic signaling. Consequently, it has been suggested that the haplotypic variants of the gene PPP1R1B that encodes DARPP-32 are associated with working memory and emotion processing. We hypothesized that PPP1R1B should have a significant influence on the network of brain regions involved in associative emotional learning that are rich in DARPP-32, namely the striatum, prefrontal cortex (comprising the medial frontal gyrus and inferior frontal gyrus (IFG)), amygdala and parahippocampal gyrus (PHG). Dynamic causal models were applied to functional MRI data to investigate how brain connectivity during an associative emotional learning task is affected by different single-nucleotide polymorphisms (SNPs) of PPP1R1B: rs879606, rs907094 and rs3764352. Compared to heterozygotes, homozygotes with GTA alleles displayed increased intrinsic connectivity between the IFG and PHG, as well as increased excitability of the PHG for negative emotional stimuli. We have also elucidated the directionality of these genetic influences. Our data suggest that homozygotes with GTA alleles involve stronger functional connections between brain areas in order to maintain activation of these regions. Homozygotes might engage a greater degree of motivational learning and integration of information to perform the emotional learning task correctly. We conclude that PPP1R1B is associated with the neural network involved in associative emotional learning.

Genetic variants within the dopaminergic system interact to modulate endocrine stress reactivity and recovery

Catecholamines modulate endocrine stress reactivity by affecting regulatory influences of extra-hypothalamic brain structures on hypothalamus-pituitary-adrenal (HPA)-axis. Therefore, we aimed to investigate combined effects of functional allelic variations that affect dopamine availability in both cortical (COMT Val¹⁵⁸Met polymorphism) and subcortical (DAT1 VNTR) brain regions on HPA-axis reactivity to psychosocial stress. By using a standardized laboratory stress task (public speaking) we obtained saliva cortisol samples during stress exposure and an extended recovery period in 100 healthy male adults. We report for the first time significant epistasis between COMT Val¹⁵⁸Met and DAT1 VNTR on cortisol response patterns. Subjects homozygous for both the Met¹⁵⁸ and the 10-repeat allele of DAT1 VNTR were characterized by markedly elevated cortisol reactivity and impaired stress recovery compared to all other groups. Our results indicate a crucial role of functional genetic variants within the dopaminergic system in the modulation of HPA-axis response patterns and highlight the need to investigate combined effects of specific candidate genes on stress-related endophenotypes.

Clinical and therapeutic aspects of Klinefelter's syndrome: sexual function

Klinefelter's syndrome (KS) is the most common sex chromosomal aberration among men, with estimated prevalence of about 1 in 500 newborn males. The classical phenotype of KS is widely recognized, but many affected subjects present only very mild signs. While the association between KS and infertility has been well documented, few studies have investigated sexual function in the KS patients. In the present paper we reviewed studies addressed to emotional processing and sexual function in KS. We searched the following databases Medline, Pubmed, Embase, for Klinefelter's syndrome, sexuality. We focus on the peculiar contribution of genetic and hormonal background, which characterizes sexual dysfunction in KS. Abnormal structure and function of the emotional brain circuits have been described in KS. These alterations were less pronounced when the patients underwent to testosterone replacement therapy suggesting that they were mediated by testosterone deficiency. Accordingly, clinical studies indicate that sexual dysfunctions, eventually present in KS, are not specifically associated with the syndrome but are related to the underlying hypogonadism. In conclusion, androgen deficiency more than chromosomal abnormality is the major pathogenic factor of sexual dysfunction in KS.

Structural and functional neuroimaging in Klinefelter (47,XXY) syndrome: a review of the literature and preliminary results from a functional magnetic resonance imaging study of language

Klinefelter (47,XXY) syndrome (KS), the most common form of sex-chromosomal aneuploidy, is characterized by physical, endocrinologic, and reproductive abnormalities. Individuals with KS also exhibit a cognitive/behavioral phenotype characterized by language and language-based learning disabilities and executive and attentional dysfunction in the setting of normal general intelligence. The underlying neurobiologic mechanisms are just now beginning to be elucidated through structural and functional neuroimaging. Here, we review the literature of structural and functional neural findings in KS identified by neuroimaging and present preliminary results from a functional magnetic resonance imaging study examining brain activity during a verb generation task in KS.

Turner syndrome: neuroimaging findings: structural and functional

Neuroimaging studies of Turner syndrome can advance our understanding of the X chromosome in brain development, and the modulatory influence of endocrine factors. There is increasing evidence from neuroimaging studies that TX individuals have significant differences in the anatomy, function, and metabolism of a number of brain regions; including the parietal lobe; cerebellum, amygdala, hippocampus; and basal ganglia; and perhaps differences in "connectivity" between frontal and parieto-occipital regions. Finally, there is preliminary evidence that genomic imprinting, sex hormones and growth hormone have significant modulatory effects on brain maturation in TS.

Emotion processing and theory of mind in schizophrenia patients and their unaffected first-degree relatives

Previous studies have suggested that social cognition is affected in individuals with schizophrenia. The purpose of this study was to explore to what extent social cognition deficits are shared by unaffected first-degree relatives, and the nature of the relationship between performance in different paradigms of social cognition. 20 Schizophrenia patients (7 females, 31+/-10 years), 20 healthy age- and gender-matched individuals, 20 unaffected first-degree relatives of the schizophrenia patients (11 females, 50+/-20 years), and 20 healthy individuals matched for age and gender were recruited. Patients showed deficits in the detection of social Faux Pas (0.80+/-0.17 vs. controls: 0.94+/-0.09, p=0.025) and the correct identification of Theory of Mind stories (0.71+/-0.13 vs. controls: 0.82+/-0.12, p=0.038). Relatives performed poorly in the Faces Test (0.83+/-0.14 vs. controls: 0.9+/-0.08, p=0.048), the Reading the Mind in the Eyes Test (0.59+/-0.17 vs. controls: 0.71+/-0.14, p=0.046) and the detection of social Faux Pas (0.8+/-0.2 vs. controls: 0.93+/-0.09, p=0.024). Abnormalities were independent of age, years of education, and general cognitive performance in patients and their relatives. Performance in an Emotion Processing task (Faces Test) was correlated with performance in theory of mind tests in healthy individuals and relatives of patients with schizophrenia only. These results suggest that schizophrenia patients and their unaffected first-degree relatives display similar but nonidentical patterns of social cognition processing.

Sexual dysfunction in subjects with Klinefelter's syndrome

While the association of Klinefelter's Syndrome (KS) with infertility is well-known, very few investigations have evaluated the prevalence of sexual dysfunction in KS. The aim of the present study was to systematically analyse the prevalence of KS in a consecutive series of adult male patients consulting for sexual problems and to investigate its specific correlates. Among a consecutive series of 1386 men (mean age 48.9 +/- 12.7 years old), 23 (1.7%) subjects with KS were found. Patients with KS were younger and more often hypogonadal when compared with the rest of the sample. Among patients with KS, five (22.7%) subjects reported severe erectile dysfunction, 14 (60.9%) hypoactive sexual desire (HSD), two (9.5%) premature and two (9.5%) delayed ejaculation. Only the association between KS and HSD was confirmed after adjustment for age [HR = 3.2 (1.37-7.5)], however, when patients with KS were compared with age, smoking habit, and testosterone matched controls, even the association between KS with HSD disappeared. In comparison to matched hypogonadal controls, subjects with KS had lower levels of education, a higher frequency of cryptorchidism and poorer pubertal progression. In conclusion, our results indicate that sexual dysfunction present in KS is not specifically associated with the syndrome but is caused by the underlying hypogonadal state. Further studies are needed to evaluate the efficacy of testosterone substitution in ameliorating the hypoactive sexual desire often reported in subjects with KS.

Musical aptitude is associated with AVPR1A-haplotypes

Artistic creativity forms the basis of music culture and music industry. Composing, improvising and arranging music are complex creative functions of the human brain, which biological value remains unknown. We hypothesized that practicing music is social communication that needs musical aptitude and even creativity in music. In order to understand the neurobiological basis of music in human evolution and communication we analyzed polymorphisms of the arginine vasopressin receptor 1A (AVPR1A), serotonin transporter (SLC6A4), catecol-O-methyltranferase (COMT), dopamin receptor D2 (DRD2) and tyrosine hydroxylase 1 (TPH1), genes associated with social bonding and cognitive functions in 19 Finnish families (n = 343 members) with professional musicians and/or active amateurs. All family members were tested for musical aptitude using the auditory structuring ability test (Karma Music test; KMT) and Carl Seashores tests for pitch (SP) and for time (ST). Data on creativity in music (composing, improvising and/or arranging music) was surveyed using a web-based questionnaire. Here we show for the first time that creative functions in music have a strong genetic component (h(2) = .84; composing h(2) = .40; arranging h(2) = .46; improvising h(2) = .62) in Finnish multigenerational families. We also show that high music test scores are significantly associated with creative functions in music (p<.0001). We discovered an overall haplotype association with AVPR1A gene (markers RS1 and RS3) and KMT (p = 0.0008; corrected p = 0.00002), SP (p = 0.0261; corrected p = 0.0072) and combined music test scores (COMB) (p = 0.0056; corrected p = 0.0006). AVPR1A haplotype AVR+RS1 further suggested a positive association with ST (p = 0.0038; corrected p = 0.00184) and COMB (p = 0.0083; corrected p = 0.0040) using haplotype-based association test HBAT. The results suggest that the neurobiology of music perception and production is likely to be related to the pathways affecting intrinsic attachment behavior.

Challenges in phenotype definition in the whole-genome era: multivariate models of memory and intelligence

Refining phenotypes for the study of neuropsychiatric disorders is of paramount importance in neuroscience. Poor phenotype definition provides the greatest obstacle for making progress in disorders like schizophrenia, bipolar disorder, Attention Deficit/Hyperactivity Disorder (ADHD), and autism. Using freely available informatics tools developed by the Consortium for Neuropsychiatric Phenomics (CNP), we provide a framework for defining and refining latent constructs used in neuroscience research and then apply this strategy to review known genetic contributions to memory and intelligence in healthy individuals. This approach can help us begin to build multi-level phenotype models that express the interactions between constructs necessary to understand complex neuropsychiatric diseases. These results are available online through the http://www.phenowiki.org database. Further work needs to be done in order to provide consensus-building applications for the broadly defined constructs used in neuroscience research.

Gene discovery through imaging genetics: identification of two novel genes associated with schizophrenia

We have discovered two genes, RSRC1 and ARHGAP18, associated with schizophrenia and in an independent study provided additional support for this association. We have both discovered and verified the association of two genes, RSRC1 and ARHGAP18, with schizophrenia. We combined a genome-wide screening strategy with neuroimaging measures as the quantitative phenotype and identified the single nucleotide polymorphisms (SNPs) related to these genes as consistently associated with the phenotypic variation. To control for the risk of false positives, the empirical P-value for association significance was calculated using permutation testing. The quantitative phenotype was Blood-Oxygen-Level Dependent (BOLD) Contrast activation in the left dorsal lateral prefrontal cortex measured during a working memory task. The differential distribution of SNPs associated with these two genes in cases and controls was then corroborated in a larger, independent sample of patients with schizophrenia (n=82) and healthy controls (n=91), thus suggesting a putative etiological function for both genes in schizophrenia. Up until now these genes have not been linked to any neuropsychiatric illness, although both genes have a function in prenatal brain development. We introduce the use of functional magnetic resonance imaging activation as a quantitative phenotype in conjunction with genome-wide association as a gene discovery tool.

Minimal acupuncture is not a valid placebo control in randomised controlled trials of acupuncture: a physiologist's perspective

Placebo-control of acupuncture is used to evaluate and distinguish between the specific effects and the non-specific ones. During 'true' acupuncture treatment in general, the needles are inserted into acupoints and stimulated until deqi is evoked. In contrast, during placebo acupuncture, the needles are inserted into non-acupoints and/or superficially (so-called minimal acupuncture). A sham acupuncture needle with a blunt tip may be used in placebo acupuncture. Both minimal acupuncture and the placebo acupuncture with the sham acupuncture needle touching the skin would evoke activity in cutaneous afferent nerves. This afferent nerve activity has pronounced effects on the functional connectivity in the brain resulting in a 'limbic touch response'. Clinical studies showed that both acupuncture and minimal acupuncture procedures induced significant alleviation of migraine and that both procedures were equally effective. In other conditions such as low back pain and knee osteoarthritis, acupuncture was found to be more potent than minimal acupuncture and conventional non-acupuncture treatment. It is probable that the responses to 'true' acupuncture and minimal acupuncture are dependent on the aetiology of the pain. Furthermore, patients and healthy individuals may have different responses. In this paper, we argue that minimal acupuncture is not valid as an inert placebo-control despite its conceptual brilliance.

A genome-wide association study of schizophrenia using brain activation as a quantitative phenotype

BACKGROUND

Genome-wide association studies (GWASs) are increasingly used to identify risk genes for complex illnesses including schizophrenia. These studies may require thousands of subjects to obtain sufficient power. We present an alternative strategy with increased statistical power over a case-control study that uses brain imaging as a quantitative trait (QT) in the context of a GWAS in schizophrenia.

METHODS

Sixty-four subjects with chronic schizophrenia and 74 matched controls were recruited from the Functional Biomedical Informatics Research Network (FBIRN) consortium. Subjects were genotyped using the Illumina HumanHap300 BeadArray and were scanned while performing a Sternberg Item Recognition Paradigm in which they learned and then recognized target sets of digits in an functional magnetic resonance imaging protocol. The QT was the mean blood oxygen level-dependent signal in the dorsolateral prefrontal cortex during the probe condition for a memory load of 3 items.

RESULTS

Three genes or chromosomal regions were identified by having 2 single-nucleotide polymorphisms (SNPs) each significant at P < 10(-6) for the interaction between the imaging QT and the diagnosis (ROBO1-ROBO2, TNIK, and CTXN3-SLC12A2). Three other genes had a significant SNP at <10(-6) (POU3F2, TRAF, and GPC1). Together, these 6 genes/regions identified pathways involved in neurodevelopment and response to stress.

CONCLUSION

Combining imaging and genetic data from a GWAS identified genes related to forebrain development and stress response, already implicated in schizophrenic dysfunction, as affecting prefrontal efficiency. Although the identified genes require confirmation in an independent sample, our approach is a screening method over the whole genome to identify novel SNPs related to risk for schizophrenia.

Imaging the genetics of brain structure and function

Imaging genetics combines brain imaging and genetics to detect genetic variation in brain structure and function related to behavioral traits, including psychiatric endpoints, cognition, and affective regulation. This special issue features extensive reviews of the current state-of-the-art of the field and adds new findings from twin and candidate gene studies on functional MRI. Here we present a brief overview and discuss a number of desirable future developments which include more specific a priori hypotheses, more standardization of MRI measurements within and across laboratories, and larger sample sizes that allows testing of multiple genes and their interactions up to a scale that allows genetic whole genome association studies. Based on the overall tenet of the contributions to this special issue we predict that imaging genetics will increasingly impact on the classification systems for psychiatric disorders and the early detection and treatment of vulnerable individuals.