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O'Nions EJP, Dolan RJ, Roiser JP. Serotonin transporter genotype modulates subgenual response to fearful faces using an incidental task. J Cogn Neurosci 2011; 23:3681-93. [PMID: 21568644 PMCID: PMC3435845 DOI: 10.1162/jocn_a_00055] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This study assessed the impact of serotonin transporter genotype (5-HTTLPR) on regional responses to emotional faces in the amygdala and subgenual cingulate cortex (sgACC), while subjects performed a gender discrimination task. Although we found no evidence for greater amygdala reactivity or reduced amygdala-sgACC coupling in short variant 5-HTTLPR homozygotes (s/s), we observed an interaction between genotype and emotion in sgACC. Only long variant homozygotes (la/la) exhibited subgenual deactivation to fearful versus neutral faces, whereas the effect in s/s subjects was in the other direction. This absence of subgenual deactivation in s/s subjects parallels a recent finding in depressed subjects [Grimm, S., Boesiger, P., Beck, J., Schuepbach, D., Bermpohl, F., Walter, M., et al. Altered negative BOLD responses in the default-mode network during emotion processing in depressed subjects. Neuropsychopharmacology, 34, 932-943, 2009]. Taken together, the findings suggest that subgenual cingulate activity may play an important role in regulating the impact of aversive stimuli, potentially conferring greater resilience to the effects of aversive stimuli in la/la subjects. Using dynamic causal modeling of functional magnetic resonance imaging data, we explored the effects of genotype on effective connectivity and emotion-specific changes in coupling across a network of regions implicated in social processing. Viewing fearful faces enhanced bidirectional excitatory coupling between the amygdala and the fusiform gyrus, and increased the inhibitory influence of the amygdala over the sgACC, although this modulation of coupling did not differ between the genotype groups. The findings are discussed in relation to the role of sgACC and serotonin in moderating responses to aversive stimuli [Dayan, P., & Huys, Q. J., Serotonin, inhibition, and negative mood. PLoS Comput Biol, 4, e4, 2008; Mayberg, H. S., Liotti, M., Brannan, S. K., McGinnis, S., Mahurin, R. K., Jerabek, P. A., et al. Reciprocal limbic-cortical function and negative mood: Converging PET findings in depression and normal sadness. Am J Psychiatry, 156, 675-682, 1999].
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A review on experimental and clinical genetic associations studies on fear conditioning, extinction and cognitive-behavioral treatment. Transl Psychiatry 2011; 1:e41. [PMID: 22832657 PMCID: PMC3309482 DOI: 10.1038/tp.2011.36] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Fear conditioning and extinction represent basic forms of associative learning with considerable clinical relevance and have been implicated in the pathogenesis of anxiety disorders. There is considerable inter-individual variation in the ability to acquire and extinguish conditioned fear reactions and the study of genetic variants has recently become a focus of research. In this review, we give an overview of the existing genetic association studies on human fear conditioning and extinction in healthy individuals and of related studies on cognitive-behavioral treatment (CBT) and exposure, as well as pathology development after trauma. Variation in the serotonin transporter (5HTT) and the catechol-o-methyltransferase (COMT) genes has consistently been associated with effects in pre-clinical and clinical studies. Interesting new findings, which however require further replication, have been reported for genetic variation in the dopamine transporter (DAT1) and the pituitary adenylate cyclase 1 receptor (ADCYAP1R1) genes, whereas the current picture is inconsistent for variation in the brain-derived neurotrophic factor (BDNF) gene. We end with a discussion of the findings and their limitations, as well as future directions that we hope will aid the field to develop further.
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Morey RA, Hariri AR, Gold AL, Hauser MA, Munger HJ, Dolcos F, McCarthy G. Serotonin transporter gene polymorphisms and brain function during emotional distraction from cognitive processing in posttraumatic stress disorder. BMC Psychiatry 2011; 11:76. [PMID: 21545724 PMCID: PMC3112079 DOI: 10.1186/1471-244x-11-76] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 05/05/2011] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Serotonergic system dysfunction has been implicated in posttraumatic stress disorder (PTSD). Genetic polymorphisms associated with serotonin signaling may predict differences in brain circuitry involved in emotion processing and deficits associated with PTSD. In healthy individuals, common functional polymorphisms in the serotonin transporter gene (SLC6A4) have been shown to modulate amygdala and prefrontal cortex (PFC) activity in response to salient emotional stimuli. Similar patterns of differential neural responses to emotional stimuli have been demonstrated in PTSD but genetic factors influencing these activations have yet to be examined. METHODS We investigated whether SLC6A4 promoter polymorphisms (5-HTTLPR, rs25531) and several downstream single nucleotide polymorphisms (SNPs) modulated activity of brain regions involved in the cognitive control of emotion in post-9/11 veterans with PTSD. We used functional MRI to examine neural activity in a PTSD group (n = 22) and a trauma-exposed control group (n = 20) in response to trauma-related images presented as task-irrelevant distractors during the active maintenance period of a delayed-response working memory task. Regions of interest were derived by contrasting activation for the most distracting and least distracting conditions across participants. RESULTS In patients with PTSD, when compared to trauma-exposed controls, rs16965628 (associated with serotonin transporter gene expression) modulated task-related ventrolateral PFC activation and 5-HTTLPR tended to modulate left amygdala activation. Subsequent to combat-related trauma, these SLC6A4 polymorphisms may bias serotonin signaling and the neural circuitry mediating cognitive control of emotion in patients with PTSD. CONCLUSIONS The SLC6A4 SNP rs16965628 and 5-HTTLPR are associated with a bias in neural responses to traumatic reminders and cognitive control of emotions in patients with PTSD. Functional MRI may help identify intermediate phenotypes and dimensions of PTSD that clarify the functional link between genes and disease phenotype, and also highlight features of PTSD that show more proximal influence of susceptibility genes compared to current clinical categorizations.
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Affiliation(s)
- Rajendra A Morey
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA.
| | - Ahmad R Hariri
- Duke-UNC Brain Imaging and Analysis Center, Duke University, Durham, NC 27705 USA,Department of Psychology & Neuroscience, and Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708 USA
| | - Andrea L Gold
- Department of Psychology, Yale University, New Haven, CT 06520 USA
| | - Michael A Hauser
- Mid-Atlantic Mental Illness Research Education and Clinical Center, Durham VA Medical Center, Durham, NC 27705 USA,Center for Human Genetics, Duke University, Durham, NC 27710 USA
| | - Heidi J Munger
- Mid-Atlantic Mental Illness Research Education and Clinical Center, Durham VA Medical Center, Durham, NC 27705 USA,Center for Human Genetics, Duke University, Durham, NC 27710 USA
| | - Florin Dolcos
- Department of Psychology, Neuroscience Program, and Beckman Institute for Advanced Science & Technology, University of Illinois, Urbana-Champaign, IL, USA
| | - Gregory McCarthy
- Mid-Atlantic Mental Illness Research Education and Clinical Center, Durham VA Medical Center, Durham, NC 27705 USA,Department of Psychology, Yale University, New Haven, CT 06520 USA
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Homberg JR, Lesch KP. Looking on the bright side of serotonin transporter gene variation. Biol Psychiatry 2011; 69:513-9. [PMID: 21047622 DOI: 10.1016/j.biopsych.2010.09.024] [Citation(s) in RCA: 322] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 09/17/2010] [Accepted: 09/18/2010] [Indexed: 12/19/2022]
Abstract
Converging evidence indicates an association of the short (s), low-expressing variant of the repeat length polymorphism, serotonin transporter-linked polymorphic region (5-HTTLPR), in the human serotonin transporter gene (5-HTT, SERT, SLC6A4) with anxiety-related traits and increased risk for depression in interaction with psychosocial adversity across the life span. However, genetically driven deficient serotonin transporter (5-HTT) function would not have been maintained throughout evolution if it only exerted negative effects without conveying any gain of function. Here, we review recent findings that humans and nonhuman primates carrying the s variant of the 5-HTTLPR outperform subjects carrying the long allele in an array of cognitive tasks and show increased social conformity. In addition, studies in 5-HTT knockout rodents are included that provide complementary insights in the beneficial effects of the 5-HTTLPR s-allele. We postulate that hypervigilance, mediated by hyperactivity in corticolimbic structures, may be the common denominator in the anxiety-related traits and (social) cognitive superiority of s-allele carriers and that environmental conditions determine whether a response will turn out to be negative (emotional) or positive (cognitive, in conformity with the social group). Taken together, these findings urge for a conceptual change in the current deficit-oriented connotation of the 5-HTTLPR variants. In fact, these factors may counterbalance or completely offset the negative consequences of the anxiety-related traits. This notion may not only explain the modest effect size of the 5-HTTLPR and inconsistent reports but may also lead to a more refined appreciation of allelic variation in 5-HTT function.
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Affiliation(s)
- Judith R Homberg
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Lemogne C, Gorwood P, Boni C, Pessiglione M, Lehéricy S, Fossati P. Cognitive appraisal and life stress moderate the effects of the 5-HTTLPR polymorphism on amygdala reactivity. Hum Brain Mapp 2011; 32:1856-67. [PMID: 21246665 DOI: 10.1002/hbm.21150] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 08/03/2010] [Indexed: 11/10/2022] Open
Abstract
The short allele of the serotonin-transporter-linked promoter region (5-HTTLPR) polymorphism is associated with increased amygdala activation in response to emotional stimuli. Although top-down processes may moderate this association, available evidence is conflicting, showing the genotype influence on amygdala reactivity to be either decreased or increased during emotion regulation. Because the effects of the 5-HTTLPR polymorphism on amygdala reactivity are also conditional on self-reported life stress, differences in life stress exposure may account for this apparent discrepancy. Here, we hypothesized that self-reported life stress would moderate the relationships between genotype, cognitive appraisal, and amygdala reactivity. Forty-five healthy never-depressed subjects were presented with emotional stimuli and performed two cognitive tasks: a self-referential task and an emotion-labeling task. Life-stress exposure was measured through a semistructured interview. First, there was a genotype × condition interaction in the right amygdala: short allele carriers displayed increased amygdala activation and decreased functional connectivity with the subgenual anterior cingulate cortex in self-referential processing versus emotion labeling. Second, in line with our hypothesis, there was a genotype × condition × stress interaction in bilateral amygdala the amygdala activation during self-referential processing was negatively correlated with self-reported life stress in short allele carriers and positively in individuals homozygous for the long allele, whereas an opposite pattern was observed during emotion labeling. These results confirm that the influence of the 5-HTTLPR polymorphism on amygdala reactivity is at least partially under cognitive control. Additionally, they suggest that measuring life stress exposure is a critical step when imaging genetics.
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Affiliation(s)
- Cédric Lemogne
- CNRS USR 3246, Pitié-Salpêtrière Hospital, Paris, France.
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56
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Pluess M, Belsky J, Way BM, Taylor SE. 5-HTTLPR moderates effects of current life events on neuroticism: differential susceptibility to environmental influences. Prog Neuropsychopharmacol Biol Psychiatry 2010; 34:1070-4. [PMID: 20573579 PMCID: PMC2915757 DOI: 10.1016/j.pnpbp.2010.05.028] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 05/26/2010] [Accepted: 05/26/2010] [Indexed: 01/21/2023]
Abstract
Research chronicling links between a polymorphism in the serotonin-transporter gene (5-HTTLPR) and neuroticism has yielded inconsistent results. One possible explanation for this inconsistency is that any gene-phenotype association is obscured by a gene-X-environment (GXE) interaction. We studied a healthy non-clinical sample (N=118) to determine whether the 5-HTTLPR interacts with current life events in predicting neuroticism. The differential-susceptibility hypothesis led to the prediction of such an interaction, reflecting the fact that individuals with short alleles would be affected more by both negative and positive life events than those homozygous for long alleles. Participants completed questionnaires concerning recent life events and neuroticism. The 5-HTTLPR was genotyped using a standard protocol with DNA extracted from oral fluid. For those homozygous for the short allele, more negative life events proved related to greater neuroticism, whereas more positive life events proved related to less neuroticism. No such association emerged in the case of those homozygous for the long allele. Whereas neuroticism is likely to be an especially stable trait in individuals homozygous for the long allele, this may be less so the case for those carrying short alleles.
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57
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Glenn AL. The other allele: exploring the long allele of the serotonin transporter gene as a potential risk factor for psychopathy: a review of the parallels in findings. Neurosci Biobehav Rev 2010; 35:612-20. [PMID: 20674598 DOI: 10.1016/j.neubiorev.2010.07.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 06/25/2010] [Accepted: 07/23/2010] [Indexed: 10/19/2022]
Abstract
Converging evidence suggests that the short allele of the serotonin transporter gene polymorphism increases risk for a variety of psychological disorders, including depression, anxiety, and alcoholism. Thus, the short allele is typically considered the "risk" allele, and findings related to the long allele are rarely discussed. However, upon closer examination, findings associated with the long allele of the serotonin transporter gene share striking similarities with findings from studies of psychopathy. Here, the parallels between findings associated with the long/long genotype and findings associated with psychopathic traits in the areas of neuropsychology, psychophysiology, hormones, and brain imaging are reviewed. It is suggested that the long/long genotype may be a potential risk factor for the development of psychopathic traits.
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Affiliation(s)
- Andrea L Glenn
- Department of Psychology, University of Pennsylvania, 3720 Walnut Street, Philadelphia, PA 19104, USA.
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58
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Relationships between affective states and decision-making. Int J Psychophysiol 2009; 74:259-65. [DOI: 10.1016/j.ijpsycho.2009.09.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Revised: 08/18/2009] [Accepted: 09/18/2009] [Indexed: 11/21/2022]
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59
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Werner NS, Jung K, Duschek S, Schandry R. Enhanced cardiac perception is associated with benefits in decision-making. Psychophysiology 2009; 46:1123-9. [DOI: 10.1111/j.1469-8986.2009.00855.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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60
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Baker DG, Nievergelt CM, Risbrough VB. Post-traumatic stress disorder: emerging concepts of pharmacotherapy. Expert Opin Emerg Drugs 2009; 14:251-72. [PMID: 19453285 DOI: 10.1517/14728210902972494] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Post-traumatic stress disorder (PTSD) can result from a traumatic experience that elicits emotions of fear, helpless or horror. Most individuals remain asymptomatic or symptoms quickly resolve, but in a minority intrusive imagery and nightmares, emotional numbing and avoidance, and hyperarousal persist for decades. PTSD is associated with psychiatric and medical co-morbidities, increased risk for suicide, and with poor social and occupational functioning. Psychotherapy and pharmacotherapy are common treatments. Whereas, research supports the efficacy of the cognitive behavioral psychotherapies, there is insufficient evidence to unequivocally support the efficacy of any specific pharmacotherapy. Proven effective pharmacologic agents are sorely needed to treat core and targeted PTSD symptoms, and for prevention. This review describes current and emerging pharmacotherapies that advance these goals.
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Affiliation(s)
- Dewleen G Baker
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive (0603V), La Jolla, California 92093, USA.
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61
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5-HTT, DRD4, and COMT genes polymorphisms are not associated with fear during childbirth in Korea. Psychiatr Genet 2009; 19:105. [PMID: 19672140 DOI: 10.1097/ypg.0b013e328320807c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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62
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Serotonin transporter genotype is associated with cognitive performance but not regional 5-HT1A receptor binding in humans. Int J Neuropsychopharmacol 2009; 12:783-92. [PMID: 19126263 DOI: 10.1017/s1461145708009759] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human serotonin transporter (5-HTT) gene is one of the most extensively studied in psychiatry. A functional polymorphism in the promoter region of the 5-HTT gene (5-HTTLPR) has been associated with several psychiatric disorders as well as anxiety-related personality traits. In search of a mechanistic understanding of the functional implications of 5-HTTLPR, the influence of this polymorphism on regional 5-HT1A receptor density has previously been examined in two positron emission tomography (PET) studies in humans, yielding, however, contradictory results. In the present study, 54 control subjects were examined with [11C]WAY 100635 PET and a battery of cognitive tests. Regional binding potential (BP) of [11C]WAY 100635 to 5-HT1A receptor was calculated for the dorsal raphe nuclei, the hippocampus, the anterior cingulate, the insula, the temporal cortex and the frontal cortex. The influence of 5-HTTLPR genotype on regional 5-HT1A BP and cognitive performance was investigated. No differences in 5-HT1A receptor density between carriers and non-carriers of the S allele were found. Thus, we could not replicate any of the previously reported associations between 5-HTTLPR and 5-HT1A density. There was, however, a highly significant association between 5-HTTLPR genotype and performance in Wisconsin Card Sorting Test; carriers of the S allele had a superior performance compared to the LL carriers. These observations suggest that functional implications of the 5-HTTLPR polymorphism are not likely to be mediated by differences in 5-HT1A expression levels and that other biomarkers must be considered for future investigations at phenotype level.
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64
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Lonsdorf TB, Weike AI, Nikamo P, Schalling M, Hamm AO, Ohman A. Genetic gating of human fear learning and extinction: possible implications for gene-environment interaction in anxiety disorder. Psychol Sci 2009; 20:198-206. [PMID: 19175757 DOI: 10.1111/j.1467-9280.2009.02280.x] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Pavlovian fear conditioning is a widely used model of the acquisition and extinction of fear. Neural findings suggest that the amygdala is the core structure for fear acquisition, whereas prefrontal cortical areas are given pivotal roles in fear extinction. Forty-eight volunteers participated in a fear-conditioning experiment, which used fear potentiation of the startle reflex as the primary measure to investigate the effect of two genetic polymorphisms (5-HTTLPR and COMTval158met) on conditioning and extinction of fear. The 5-HTTLPR polymorphism, located in the serotonin transporter gene, is associated with amygdala reactivity and neuroticism, whereas the COMTval158met polymorphism, which is located in the gene coding for catechol-O-methyltransferase (COMT), a dopamine-degrading enzyme, affects prefrontal executive functions. Our results show that only carriers of the 5-HTTLPR s allele exhibited conditioned startle potentiation, whereas carriers of the COMT met/met genotype failed to extinguish conditioned fear. These results may have interesting implications for understanding gene-environment interactions in the development and treatment of anxiety disorders.
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Affiliation(s)
- Tina B Lonsdorf
- Department of Clinical Neuroscience, Psychology Section, Karolinska Institutet, Stockholm, Sweden.
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65
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Murphy DL, Fox MA, Timpano KR, Moya PR, Ren-Patterson R, Andrews AM, Holmes A, Lesch KP, Wendland JR. How the serotonin story is being rewritten by new gene-based discoveries principally related to SLC6A4, the serotonin transporter gene, which functions to influence all cellular serotonin systems. Neuropharmacology 2008; 55:932-60. [PMID: 18824000 PMCID: PMC2730952 DOI: 10.1016/j.neuropharm.2008.08.034] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Revised: 08/15/2008] [Accepted: 08/15/2008] [Indexed: 12/19/2022]
Abstract
Discovered and crystallized over sixty years ago, serotonin's important functions in the brain and body were identified over the ensuing years by neurochemical, physiological and pharmacological investigations. This 2008 M. Rapport Memorial Serotonin Review focuses on some of the most recent discoveries involving serotonin that are based on genetic methodologies. These include examples of the consequences that result from direct serotonergic gene manipulation (gene deletion or overexpression) in mice and other species; an evaluation of some phenotypes related to functional human serotonergic gene variants, particularly in SLC6A4, the serotonin transporter gene; and finally, a consideration of the pharmacogenomics of serotonergic drugs with respect to both their therapeutic actions and side effects. The serotonin transporter (SERT) has been the most comprehensively studied of the serotonin system molecular components, and will be the primary focus of this review. We provide in-depth examples of gene-based discoveries primarily related to SLC6A4 that have clarified serotonin's many important homeostatic functions in humans, non-human primates, mice and other species.
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Affiliation(s)
- Dennis L Murphy
- Laboratory of Clinical Science, NIMH Intramural Research Program, NIH, Building 10, Room 3D41, 10 Center Drive, MSC 1264, Bethesda, MD 20892, USA.
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66
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Michael T, Ehlers A. Klassische Konditionierung als Erklärungsprinzip für klinisch bedeutsame Ängste. ZEITSCHRIFT FUR KLINISCHE PSYCHOLOGIE UND PSYCHOTHERAPIE 2008. [DOI: 10.1026/1616-3443.37.4.221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Zusammenfassung. Hintergrund: In modernen Diathese-Stress Modellen von psychischen Störungen (insbesondere Angststörungen) werden individuelle Unterschiede beim Herstellen von Assoziationen zwischen furchtrelevanten Informationen und unterschiedliche Lernumwelten als zentrale Mechanismen betrachtet. Diese erneute Betonung von klassischen Konditionierungsprozessen beruht auf dem differenzierten kognitiven und biologischen Wissensstand über klassische Konditionierung, der allerdings innerhalb der Klinischen Psychologie noch unzureichend bekannt ist. Ziel: Diese Überblicksarbeit soll daher einen Einblick in die für die Klinische Psychologie relevantesten Befunde moderner Konditionierungsforschung geben. Es wird beispielhaft erläutert, inwiefern Lernprozesse an klinischen Problemen beteiligt sind. Schlussfolgerungen: Assoziationslernen ist ein wichtiger Prozess bei der Entstehung und Aufrechterhaltung von Angststörungen und hilft zu verstehen, warum unterschiedliche Menschen verschieden auf gleiche bzw. ähnliche aversive Ereignisse reagieren. Des Weiteren wird gezeigt, dass neue innovative Interventionsmethoden (z.B. Kombination von D-Cycloserine und Exposition) auf einem umfassenden Verständnis von Klassischer Konditionierung beruhen.
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Affiliation(s)
- Tanja Michael
- Universität Basel und Institute of Psychiatry, London
| | - Anke Ehlers
- Universität Basel und Institute of Psychiatry, London
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67
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Sheehan W, Meller WH, Thurber S. More on Darwin's illness: comment on the final diagnosis of Charles Darwin. NOTES AND RECORDS OF THE ROYAL SOCIETY OF LONDON 2008; 62:205-209. [PMID: 19069001 DOI: 10.1098/rsnr.2007.0008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Without the possibility of confirmatory exhumation, diagnostic inferences about Darwin's illness must remain speculative. A diagnosis of Darwin's aggregate symptoms must account for not only gastrointestinal distress but also his predominant and excessive retching and the conglomerate of other heterogeneous symptoms. We opine that Crohn's disease, posited as the 'final diagnosis', is not sufficient for subsuming his pleiomorphic symptomatology. An additional proposal is outlined that may help to explain his presentation with heterogeneous symptoms. It incorporates constitutional vulnerabilities, psychosomatic influences and Pavlovian conditioning as explanatory variables.
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Affiliation(s)
- William Sheehan
- Swift County-Benson Hospital, 1815 Wisconsin Avenue, Benson, MN 56215, USA
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68
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Fisher PM, Muñoz KE, Hariri AR. Identification of neurogenetic pathways of risk for psychopathology. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2008; 148C:147-53. [PMID: 18412103 DOI: 10.1002/ajmg.c.30173] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Imaging genetics has been a highly effective and increasingly applied strategy for identifying the impact of genetic polymorphisms on individual differences in neural circuitry supporting complex behaviors. The application of imaging genetics towards further elucidating neural circuitry associated with the pathophysiology of psychiatric illness is of particular interest given its potential to guide the development and improvement of current therapeutic methods. The identification of genetic variants that contribute to or predict the disruption of specific neural pathways associated with psychopathology may also serve as useful markers of risk demarcating individuals with elevated susceptibility for psychiatric illness and affording early or even preemptive treatment strategies. In the continued development of this technique, recent multimodal neuroimaging strategies and studies examining the effects of multiple genes in concert within large subject populations have shown promise in the development of a more complete understanding of the interrelationships between genes, brain function, behavior and associated risk for psychopathology.
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69
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Bigos KL, Hariri AR. Neuroimaging: technologies at the interface of genes, brain, and behavior. Neuroimaging Clin N Am 2008; 17:459-67, viii. [PMID: 17983963 DOI: 10.1016/j.nic.2007.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuroimaging technologies provide a powerful approach to exploring the genetic basis of individual differences in complex behaviors and vulnerability to neuropsychiatric illness. Functional MRI studies have established important physiologic links between genetic polymorphisms and robust differences in information processing within distinct brain regions and circuits that have been linked to the manifestation of various disease. Neuroimaging technologies represent a critical tool in efforts to understand the neurobiology of normal and pathologic behavioral states. Research capitalizing on neuroimagingbased integration will contribute to the identification of predictive markers and biologic pathways for neuropsychiatric disease vulnerability and the generation of novel targets for therapeutic intervention.
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Affiliation(s)
- Kristin L Bigos
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA 15213, USA
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70
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Smolka MN, Bühler M, Schumann G, Klein S, Hu XZ, Moayer M, Zimmer A, Wrase J, Flor H, Mann K, Braus DF, Goldman D, Heinz A. Gene-gene effects on central processing of aversive stimuli. Mol Psychiatry 2007; 12:307-17. [PMID: 17211439 DOI: 10.1038/sj.mp.4001946] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Emotional reactivity and regulation are fundamental to human behavior. As inter-individual behavioral variation is affected by a multitude of different genes, there is intense interest to investigate gene-gene effects. Functional sequence variation at two genes has been associated with response and resiliency to emotionally unpleasant stimuli. These genes are the catechol-O-methyltransferase gene (COMT Val158Met) and the regulatory region (5-HTTLPR) of the serotonin transporter gene. Recently, it has been proposed that 5-HTT expression is not only affected by the common S/L variant of 5-HTTLPR but also by an A to G substitution. Using functional magnetic resonance imaging, we assessed the effects of COMT Val(158)Met and both 5-HTT genotypes on brain activation by standardized affective visual stimuli (unpleasant, pleasant, and neutral) in 48 healthy subjects. Based on previous studies, the analysis of genotype effects was restricted to limbic brain areas. To determine allele-dose effects, the number of COMT Met158 alleles (i.e., lower activity of COMT) and the number of 5-HTT low expressing alleles (S and G) was correlated with the blood oxygen level-dependent (BOLD) response to pleasant or unpleasant stimuli compared to neutral stimuli. We observed an additive effect of COMT and both 5-HTT polymorphisms, accounting for 40% of the inter-individual variance in the averaged BOLD response of amygdala, hippocampal and limbic cortical regions elicited by unpleasant stimuli. Effects of 5-HTT and COMT genotypes did not affect brain processing of pleasant stimuli. These data indicate that functional brain imaging may be used to assess the interaction of multiple genes on the function of neuronal networks.
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Affiliation(s)
- M N Smolka
- Department of Psychiatry, Technische Universität Dresden, Dresden, Germany
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71
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Reimold M, Smolka MN, Schumann G, Zimmer A, Wrase J, Mann K, Hu XZ, Goldman D, Reischl G, Solbach C, Machulla HJ, Bares R, Heinz A. Midbrain serotonin transporter binding potential measured with [11C]DASB is affected by serotonin transporter genotype. J Neural Transm (Vienna) 2007; 114:635-9. [PMID: 17225932 DOI: 10.1007/s00702-006-0609-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 11/02/2006] [Indexed: 12/16/2022]
Abstract
BACKGROUND Homozygote carriers of two long (L) alleles of the serotonin transporter (5-HTT) regulatory region displayed in vitro a twofold increase in 5-HTT expression compared with carriers of one or two short (S) alleles. However, in vivo imaging studies yielded contradictory results. Recently, an A > G exchange leading to differential transcriptional activation of 5-HTT mRNA in lymphobalstoid cell lines was discovered in the 5-HTT regulatory region. In vitro and in vivo evidence suggests that [(11)C]DASB, a new 5-HTT ligand offers some advantages over the ligands used in previous studies in measuring 5-HTT density independent of synaptic levels of serotonin. METHOD We assessed 5-HTT binding potential (BP (2)) in the midbrain of 19 healthy subjects with positron emission tomography and [(11)C]DASB. Accounting for the hypothesized functional similarity of L (G) and S in driving 5-HTT transcription, we assessed whether L (A) L (A) homozygotes display increased midbrain BP (2) compared with carriers of at least one S allele. RESULTS BP (2) in the midbrain was significantly increased in L (A) L (A) homozygotes compared with carriers of at least one S allele. Interestingly, the genotype effect on the midbrain was significantly different from that on the thalamus and the amygdala where no group differences were detected. CONCLUSIONS This in vivo study provides further evidence that subjects homozygous for the L (A) allele display increased expression of 5-HTT in the midbrain, the origin of central serotonergic projections.
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Affiliation(s)
- M Reimold
- Department of Nuclear Medicine and PET Center, University of Tübingen, Tübingen, Germany
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72
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Viding E, Williamson DE, Hariri AR. Developmental imaging genetics: challenges and promises for translational research. Dev Psychopathol 2007; 18:877-92. [PMID: 17152405 DOI: 10.1017/s0954579406060433] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Advances in molecular biology, neuroimaging, genetic epidemiology, and developmental psychopathology have provided a unique opportunity to explore the interplay of genes, brain, and behavior within a translational research framework. Herein, we begin by outlining an experimental strategy by which genetic effects on brain function can be explored using neuroimaging, namely, imaging genetics. We next describe some major findings in imaging genetics to highlight the effectiveness of this strategy for delineating biological pathways and mechanisms by which individual differences in brain function emerge and potentially bias behavior and risk for psychiatric illness. We then discuss the importance of applying imaging genetics to the study of psychopathology within a developmental framework. By beginning to move toward a systems-level approach to understanding pathways to behavioral outcomes as they are expressed across development, it is anticipated that we will move closer to understanding the complexities of the specific mechanisms involved in the etiology of psychiatric disease. Despite the numerous challenges that lie ahead, we believe that developmental imaging genetics has potential to yield highly informative results that will ultimately translate into public health benefits. We attempt to set out guidelines and provide exemplars that may help in designing fruitful translational research applications that incorporate a developmental imaging genetics strategy.
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73
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Finger EC, Marsh AA, Buzas B, Kamel N, Rhodes R, Vythilingham M, Pine DS, Goldman D, Blair JR. The impact of tryptophan depletion and 5-HTTLPR genotype on passive avoidance and response reversal instrumental learning tasks. Neuropsychopharmacology 2007; 32:206-15. [PMID: 16900105 DOI: 10.1038/sj.npp.1301182] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Transient reductions in serotonin levels during tryptophan depletion (TD) are thought to impair reward processing in healthy volunteers, while another facet of the serotonergic system, the serotonin transporter (5-HTTLPR) short allele polymorphism, is implicated in augmented processing of aversive stimuli. We examined the impact and interactions of TD and the serotonin promoter polymorphism genotype on reward and punishment via two forms of instrumental learning: passive avoidance and response reversal. In this study, healthy volunteers (n=35) underwent rapid TD or control procedures and genotyping (n=26) of the 5-HTTLPR for long and short allele variants. In the passive avoidance task, tryptophan-depleted volunteers failed to respond sufficiently to rewarded stimuli compared to the control group. Additionally, long allele homozygous individuals (n=11) were slower to learn to avoid punished stimuli compared to short allele carriers (n=15). TD alone did not produce measurable deficits in probabilistic response reversal errors. However, a significant drug group by genotype interaction was found indicating that in comparison to short allele carriers, tryptophan-depleted individuals homozygous for the long allele failed to appropriately use punishment information to guide responding. These findings extend prior reports of impaired reward processing in TD to include instrumental learning. Furthermore, they demonstrate behavioral differences in responses to punishing stimuli between long allele homozygotes and short allele carriers when serotonin levels are acutely reduced.
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Affiliation(s)
- Elizabeth C Finger
- Mood and Anxiety Disorders Program, Unit on Affective Cognitive Neuroscience, National Institute of Mental Health, Bethesda, MD 20892, USA.
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74
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Abstract
CONTEXT Bipolar/panic comorbidity has been observed in clinical, community and familial samples. As both are episodic disorders of affect regulation, the common pathophysiological mechanism is likely to involve deficits in amygdala-mediated, plasticity-dependent emotional conditioning. EVIDENCE Neuronal genesis and synaptic remodeling occur in the amygdala; bipolar and panic disorders have both been associated with abnormality in the amygdala and related structures, as well as in molecules that modulate plasticity, such as serotonin, norepinephrine, brain-derived neurotrophic factor (BDNF) and corticotrophin releasing factor (CRF). These biological elements are involved in behavioral conditioning to threat and reward. MODEL Panic attacks resemble the normal acute fear response, but are abnormally dissociated from any relevant threat. Abnormal reward-seeking behavior is central to both manic and depressive syndromes. Appetites can be elevated or depressed; satisfaction of a drive may fail to condition future behavior. These dissociations may be the result of deficits in plasticity-dependent processes of conditioning within different amygdala subregions. CONCLUSIONS This speculative model may be a useful framework with which to connect molecular, cellular, anatomic and behavioral processes in panic and bipolar disorders. The primary clinical implication is that behavioral treatment may be critical to restore function in some bipolar patients who respond only partially to medications.
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Affiliation(s)
- Dean F MacKinnon
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Meyer 3-181, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
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75
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Hensch T, Wargelius HL, Herold U, Lesch KP, Oreland L, Brocke B. Further evidence for an association of 5-HTTLPR with intensity dependence of auditory-evoked potentials. Neuropsychopharmacology 2006; 31:2047-54. [PMID: 16421513 DOI: 10.1038/sj.npp.1301020] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intensity dependence of auditory-evoked potentials (IAEP) has been suggested as an indicator of central serotonergic neurotransmission. Two recent studies investigated a possible association of IAEP with a functional polymorphism in the transcriptional control region of the serotonin transporter gene (5-HTTLPR) that has a short (s) and a long (l) variant. Although both studies found an association between 5-HTTLPR and IAEP, Gallinat et al found l/l individuals to exhibit lower IAEP, whereas Strobel et al observed stronger IAEP in l/l individuals. These conflicting results require further evaluation and more attention needs to be paid to variables that are known to be confounded with the effects of IAEP and 5-HTTLPR. Using a paradigm comparable to Strobel et al, the present study analyzes the effect of 5-HTTLPR on IAEP in a healthy male student sample (N=91; age=23 years, SD=1.9) that was homogenous for most significant confounding variables. A stronger IAEP was shown in l/l individuals, irrespective of the method of IAEP parametrization. This also held at retest after 3 weeks in a subsample (N=18). Given the successful replication of Strobel et al, several possible reasons for conflicting results with regard to Gallinat et al are discussed. It is argued that the most significant difference between Gallinat et al on the one hand, and Strobel et al and this study on the other, is that different intensity ranges are used which impact IAEP. Therefore, this study encourages further analysis of dose dependence of results.
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Affiliation(s)
- Tilman Hensch
- Department of Psychology, Dresden University of Technology, Dresden, Germany.
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76
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Javanbakht A. Sensory gating deficits, pattern completion, and disturbed fronto-limbic balance, a model for description of hallucinations and delusions in schizophrenia. Med Hypotheses 2006; 67:1173-84. [PMID: 16824690 DOI: 10.1016/j.mehy.2006.03.054] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 03/29/2006] [Accepted: 03/30/2006] [Indexed: 11/17/2022]
Abstract
Schizophrenia, if not the most difficult, is one of the most difficult mysterious puzzles for psychiatrists, psychologists, and neuroscientists to solve. In this paper, based on the previously known pathologies of schizophrenia, a new model is proposed for explanation of the formation of positive psychotic symptoms of hallucinations and delusions. This model can be used for understanding psychotic or psychotic-like positive symptoms of bipolar mood disorder, posttraumatic stress disorder, obsessive compulsive, and amphetamine and drug-induced psychotic disorders. Based on the postulated model, a spectral view on these disorders with psychotic features is also proposed. These pathologies include auditory sensory gating deficits in hippocampus, abnormal emotional coding in amygdala, pattern completion in thalamic and cortical areas, and disturbed fronto-limbic balance. This model includes anatomical and neurotransmitter defects of hippocampus, amygdala, thalamus, cingula, and prefrontal cortex and their interconnections. A role for hippocampal sensory gating deficits in the pathogenesis of positive psychotic symptoms and interrelation between amygdala and its dopamine level with hippocampus is speculated. This model also hires the interesting function of pattern completion in thalamus and cortical areas for a better explanation of the pathogenesis of hallucinations and delusional psychotic symptoms. Furthermore, there is also explanation for the polygenic etiology of the schizophrenic and psychotic disorders and relation between schizophrenia and bipolar mood disorder in anatomy and neural systems involved. A spectral view is proposed that explains the absence of clear cut border between different psychotic or psychotic-like disorders in their form and severity based on the involved genes and brain functional systems. Including excessive prefrontal pruning, there is also explanation for the appearance of positive psychotic symptoms in early adulthood. An explanation for the high dopamine level of amygdala despite its decreased size and abnormal anatomy is also suggested as a compensatory function which might explain the decline in positive psychotic symptoms when schizophrenics age according to amygdala burn out. Based on this model, speculations are provided for: late onset of the effects of antipsychotics on positive psychotic symptoms, mechanism for the therapeutic effect of serotonin type 2A receptor blockers and GABAergic medications in psychosis, role of smoking in diminution of psychotic symptoms, and relationship between biological and psychological issues in the formation of psychotic symptoms. Finally, based on this model, a new role for nicotinic cholinergic drugs (such as galantamine) for treatment of schizophrenia and other psychotic or psychotic-like disorders is proposed.
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Affiliation(s)
- Arash Javanbakht
- Ibn E Sina Psychiatric Hospital, Mashhad University of Medical Sciences, No. 180 Banafsheh Street, Sajjad Boulevard, Mashhad 91876, Iran
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van Belzen MJ, Heutink P. Genetic analysis of psychiatric disorders in humans. GENES BRAIN AND BEHAVIOR 2006; 5 Suppl 2:25-33. [PMID: 16681798 DOI: 10.1111/j.1601-183x.2006.00223.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Psychiatric disorders place a large burden not only on affected individuals and their families but also on societies and health services. Current treatment is only effective in a proportion of the patients, so considerable effort has been put into the development of new medications. The susceptibility to all major psychiatric disorders is, at least in part, genetic. Knowledge of the genes that underlie this susceptibility may lead to the identification of new drug targets and the development of more effective treatments. Therefore, numerous genetic studies in search for the genes involved in psychiatric disorders have been performed. Although results of both linkage and association studies have been inconsistent, several promising gene regions and candidate genes have been identified recently. In this article, we will review the strategies that proved to be successful in detecting genes for psychiatric disorders and we will provide some recommendations to increase the probability of detecting susceptibility genes in genetic studies of different designs.
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Affiliation(s)
- M J van Belzen
- Department of Medical Genomics, Center for Neurogenomics and Cognitive Research, VU University Medical Center and VU University, Amsterdam, The Netherlands
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78
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Hariri AR, Drabant EM, Weinberger DR. Imaging genetics: perspectives from studies of genetically driven variation in serotonin function and corticolimbic affective processing. Biol Psychiatry 2006; 59:888-97. [PMID: 16442081 DOI: 10.1016/j.biopsych.2005.11.005] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 11/01/2005] [Accepted: 11/14/2005] [Indexed: 11/16/2022]
Abstract
Advances in molecular biology and neuroimaging have provided a unique opportunity to explore the relationships between genes, brain, and behavior. In this review, we will briefly outline the rationale for studying genetic effects on brain function with neuroimaging. We will then use studies of genetically driven variation in serotonin transporter function on corticolimbic structure and function to highlight the effectiveness of this strategy to delineate biological pathways and mechanisms by which individual differences in brain function emerge and potentially bias behavior and risk for psychiatric illness. In a series of studies, a relatively frequent regulatory variant of the human serotonin transporter gene (5-HTTLPR) has been demonstrated to bias the reactivity of the amygdala to salient environmental cues. Moreover, the 5-HTTLPR affects the development of a broader corticolimbic circuit and alters the functional integration of emotional information between the amygdala and medial prefrontal cortex. In turn, corticolimbic circuit function predicts individual differences in an experimental index of temperamental anxiety and, thus, might reflect a predictive biological marker of increased risk for mood disorders associated with the 5-HTTLPR.
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Affiliation(s)
- Ahmad R Hariri
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213-2593, USA
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79
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Suzuki A, Hoshino T, Shigemasu K. Measuring individual differences in sensitivities to basic emotions in faces. Cognition 2006; 99:327-53. [PMID: 15993402 DOI: 10.1016/j.cognition.2005.04.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 04/08/2005] [Indexed: 11/22/2022]
Abstract
The assessment of individual differences in facial expression recognition is normally required to address two major issues: (1) high agreement level (ceiling effect) and (2) differential difficulty levels across emotions. We propose a new assessment method designed to quantify individual differences in the recognition of the six basic emotions, 'sensitivities to basic emotions in faces.' We attempted to address the two major assessment issues by using morphing techniques and item response theory (IRT). We used morphing to create intermediate, mixed facial expression stimuli with various levels of recognition difficulty. Applying IRT enabled us to estimate the individual latent trait levels underlying the recognition of respective emotions (sensitivity scores), unbiased by stimulus properties that constitute difficulty. In a series of two experiments we demonstrated that the sensitivity scores successfully addressed the two major assessment issues and their concomitant individual variability. Intriguingly, correlational analyses of the sensitivity scores to different emotions produced orthogonality between happy and non-happy emotion recognition. To our knowledge, this is the first report of the independence of happiness recognition, unaffected by stimulus difficulty.
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Affiliation(s)
- Atsunobu Suzuki
- Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
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80
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Abstract
Biogenic amine neurotransmitters are released from nerve terminals and activate pre- and postsynaptic receptors. Released neurotransmitters are sequestered by transporters into presynaptic neurons, a major mode of their inactivation in the brain. Genetic studies of human biogenic amine transporter genes, including the dopamine transporter (hDAT; SLC6A3), the serotonin transporter (hSERT; SLC6A4), and the norepinephrine transporter (hNET; SLC6A2) have provided insight into how genomic variations in these transporter genes influence pharmacology and brain physiology. Genetic variants can influence transporter function by various mechanisms, including substrate affinities, transport velocity, transporter expression levels (density), extracellular membrane expression, trafficking and turnover, and neurotransmitter release. It is increasingly apparent that genetic variants of monoamine transporters also contribute to individual differences in behavior and neuropsychiatric disorders. This chapter summarizes current knowledge of transporters with a focus on genomic variations, expression variations, pharmacology of protein variants, and known association with human diseases.
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Affiliation(s)
- Z Lin
- Department of Psychiatry, Harvard Medical School, Division of Neurochemistry, New England Primate Research Center, 1 Pine Hill Drive, Southborough, MA 01772-9102, USA
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81
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Clark L, Roiser JP, Cools R, Rubinsztein DC, Sahakian BJ, Robbins TW. Stop signal response inhibition is not modulated by tryptophan depletion or the serotonin transporter polymorphism in healthy volunteers: implications for the 5-HT theory of impulsivity. Psychopharmacology (Berl) 2005; 182:570-8. [PMID: 16163530 DOI: 10.1007/s00213-005-0104-6] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Accepted: 06/17/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Reduced serotonin neurotransmission is implicated in disorders of impulse control, but the involvement of serotonin in inhibitory processes in healthy human subjects remains unclear. OBJECTIVES To investigate the effects of an acute manipulation of serotonin and genotype at a functional polymorphism in a gene coding for the serotonin transporter (5-HTT) on an established measure of response inhibition. METHODS Serotonin function was reduced by the acute tryptophan depletion (ATD) procedure in a double-blind, crossover design in 42 healthy subjects. The Stop Signal Task (SST) was administered 5-7 h after drink administration. The influences of 5-HTT polymorphism, gender and trait impulsivity were investigated. RESULTS ATD was associated with significant depletion of plasma tryptophan levels but did not increase the stop signal reaction time in comparison to the balanced (placebo) amino acid mixture. Subjects possessing the short allele of the 5-HTT polymorphism were not more impulsive on the SST than subjects homozygous for the long allele under placebo conditions and were not disproportionately sensitive to the effects of ATD. There was no effect of gender or trait impulsivity on ATD-induced change. CONCLUSIONS We find no support for the involvement of brain serotonin neurotransmission in this form of inhibitory control in healthy human subjects.
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Affiliation(s)
- L Clark
- Department of Experimental Psychology, University of Cambridge, Downing Street, and Department of Medical Genetics, Addenbrooke's Hospital, Cambridge, UK.
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82
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Cools R, Calder AJ, Lawrence AD, Clark L, Bullmore E, Robbins TW. Individual differences in threat sensitivity predict serotonergic modulation of amygdala response to fearful faces. Psychopharmacology (Berl) 2005; 180:670-9. [PMID: 15772862 DOI: 10.1007/s00213-005-2215-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Accepted: 02/10/2005] [Indexed: 11/24/2022]
Abstract
RATIONALE In this study we used functional magnetic resonance imaging (fMRI) to examine the effects of acute tryptophan depletion (ATD), a well-recognised method for inducing transient cerebral serotonin depletion, on brain activation to fearful faces. OBJECTIVES We predicted that ATD would increase the responsiveness of the amygdala to fearful faces as a function of individual variation in threat sensitivity. METHODS Twelve healthy male volunteers received a tryptophan depleting drink or a tryptophan balancing amino acid drink (placebo) in a double-blind crossover design. Five hours after drink ingestion participants were scanned whilst viewing fearful, happy and neutral faces. RESULTS Consistent with previous findings, fearful faces induced significant signal change in the bilateral amygdala/hippocampus as well as the fusiform face area and the right dorsolateral prefrontal cortex. Furthermore, ATD modulated amygdala/hippocampus activation in response to fearful relative to happy faces as a function of self-reported threat sensitivity (as measured with the Behavioral Inhibition Scale; Carver CS, White TL (1994) Behavioral inhibition, behavioral activation, and affective responses to impending reward and punishment: the BIS/BAS scales. J Pers Soc Psychol 67:319-333). CONCLUSION The data support the hypothesis that individual variation in threat sensitivity interacts with manipulation of 5-HT function to bias the processing of amygdala-dependent threat-relevant stimuli.
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Affiliation(s)
- Roshan Cools
- MRC Behavioural and Clinical Neuroscience Centre.
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83
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Dragan WŁ, Oniszczenko W. Polymorphisms in the serotonin transporter gene and their relationship to two temperamental traits measured by the formal characteristics of behavior-temperament inventory: activity and emotional reactivity. Neuropsychobiology 2005; 51:269-74. [PMID: 15905633 DOI: 10.1159/000085823] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Results obtained in earlier studies indicate that 5-HTT gene polymorphisms may have a certain impact on individual differences with respect to temperamental traits. The aim of our study was to determine whether the occurrence of various alleles of the serotonin transporter gene is related to the variability of two temperamental traits postulated in the Regulative Theory of Temperament (RTT)--activity and emotional reactivity. We have demonstrated that the 5-HTTLPR polymorphism is associated with one of the RTT temperamental traits--activity. Neither the relationship between the regulatory region polymorphism and emotional reactivity nor the association between the intron 2 VNTR polymorphism and the temperamental traits under study has been confirmed.
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Affiliation(s)
- Wojciech Ł Dragan
- Faculty of Psychology, University of Warsaw, Stawki 5-7, PL-00-183 Warsaw, Poland.
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84
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Graff-Guerrero A, De la Fuente-Sandoval C, Camarena B, Gómez-Martin D, Apiquián R, Fresán A, Aguilar A, Méndez-Núñez JC, Escalona-Huerta C, Drucker-Colín R, Nicolini H. Frontal and limbic metabolic differences in subjects selected according to genetic variation of the SLC6A4 gene polymorphism. Neuroimage 2005; 25:1197-204. [PMID: 15850737 DOI: 10.1016/j.neuroimage.2004.12.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 11/26/2004] [Accepted: 12/07/2004] [Indexed: 11/20/2022] Open
Abstract
Allelic variants in the promoter region of the serotonin transporter (5-HTT) gene have been implicated in several psychiatric disorders and personality traits. In particular, two common alleles in a variable repeat sequence of the promoter region (SLC6A4) have been differentially associated with a display of abnormal levels of anxiety and affective illness in individuals carrying the "s" allele. The aim of this study was to compare the basal cerebral metabolic activity of non-psychiatric subjects in fronto-limbic structures to determine whether differences exist in basal metabolic activity within this functional polymorphism. PET scans with fluorine-18 fluorodeoxyglucose as radiotracer were performed in 71 non-psychiatric subjects previously screened for psychopathology and subsequently genotyped for SLC6A4; PET images were compared with SPM2 according to s/s (n = 27), s/l (n = 25), and l/l (n = 19) groups considering a significance threshold in a priori selected areas of P < 0.001 and an extent threshold > or =5 voxels. The analysis showed an effect of interest among the three genotype groups in right anterior cingulate gyrus (ACC), left middle frontal gyrus, and left posterior cingulate gyrus (PCC). Comparison between l/l vs. s/s showed increased metabolism for l/l in left middle frontal gyrus and an increase for s/s in right ACC and left PCC. Comparison between s/s vs. s/l showed an increase for s/s in left PCC and right ACC. Increased basal metabolism in fronto-limbic structures for the s/s group may be conceived as an "overactive metabolic state" of these structures, possibly related to an increased susceptibility for developing an anxiety-depression spectrum disorder.
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Affiliation(s)
- A Graff-Guerrero
- Laboratorio de Neurofisiología Integrativa, Instituto Nacional de Psiquiatría Ramón de la Fuente, Mexico City, Mexico.
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85
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Frans O, Rimmö PA, Aberg L, Fredrikson M. Trauma exposure and post-traumatic stress disorder in the general population. Acta Psychiatr Scand 2005; 111:291-9. [PMID: 15740465 DOI: 10.1111/j.1600-0447.2004.00463.x] [Citation(s) in RCA: 299] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To examine the lifetime prevalence of trauma experiences and post-traumatic stress disorder (PTSD). METHOD Questionnaire-assessed PTSD, the type of traumatic event experienced, perceived trauma impact, and trauma frequency in 1824 randomly selected men and women. RESULTS PTSD lifetime prevalence was estimated at 5.6% with a 1 : 2 male-to-female ratio, in spite of men reporting greater trauma exposure. The highest PTSD risk was associated with sexual and physical assault, robbery and multiple trauma experiences. Controlling for trauma type did not account for gender differences, while controlling for experienced distress did. CONCLUSION The conditional probability for PTSD varied as a function of trauma type, frequency and impact of the event, with increased rates associated with prevalent trauma exposure and higher perceived distress. The latter accounted for the gender effect, suggesting that gender differences in PTSD in part represent a generally greater vulnerability to stress in women.
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Affiliation(s)
- O Frans
- Department of Psychology, Uppsala University, Uppsala, Sweden.
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86
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Winterer G, Hariri AR, Goldman D, Weinberger DR. Neuroimaging and Human Genetics. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 67:325-83. [PMID: 16291027 DOI: 10.1016/s0074-7742(05)67010-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Georg Winterer
- Genes, Cognition and Psychosis Program, National Institute of Mental Health National Institutes of Health, Bethesda, Maryland 20892, USA
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87
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Abstract
The past decade has seen a rapid progression in our knowledge of the neurobiological basis of fear and anxiety. Specific neurochemical and neuropeptide systems have been demonstrated to play important roles in the behaviors associated with fear and anxiety-producing stimuli. Long-term dysregulation of these systems appears to contribute to the development of anxiety disorders, including panic disorder, posttraumatic stress disorder (PTSD), and social anxiety disorder. These neurochemical and neuropeptide systems have been shown to have effects on distinct cortical and subcortical brain areas that are relevant to the mediation of the symptoms associated with anxiety disorders. Moreover, advances in molecular genetics portend the identification of the genes that underlie the neurobiological disturbances that increase the vulnerability to anxiety disorders. This chapter reviews clinical research pertinent to the neurobiological basis of anxiety disorders. The implications of this synthesis for the discovery of anxiety disorder vulnerability genes and novel psychopharmacological approaches will also be discussed.
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Affiliation(s)
- A Neumeister
- Mood and Anxiety Disorders Research Program, National Institute of Mental Health/NIH, 15K North Drive, MSC 2670, Bethesda MD, 20892-2670, USA.
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88
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Bauman MD, Amaral DG. The distribution of serotonergic fibers in the macaque monkey amygdala: An immunohistochemical study using antisera to 5-hydroxytryptamine. Neuroscience 2005; 136:193-203. [PMID: 16182456 DOI: 10.1016/j.neuroscience.2005.07.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 07/17/2005] [Accepted: 07/26/2005] [Indexed: 11/27/2022]
Abstract
Though both the amygdala and the serotonin system appear to play critical roles in regulating fear and anxiety, little is known regarding the organization of serotonergic inputs to the primate amygdala. The present study employed immunohistochemistry to determine the distribution of serotonin fibers in the macaque amygdala. The brains of three adult male Macaca fascicularis monkeys were prepared for histological analysis using a polyclonal antibody to serotonin. The macaque amygdala is densely innervated by serotonergic fibers and demonstrates a distinctive pattern of fiber distribution and density among the 13 nuclei and cortical areas. The highest density of 5-hydroxytryptamine immunoreactive fibers is observed in the central nucleus, the nucleus of the lateral olfactory tract, the paralaminar nucleus, the anterior amygdaloid area and a small region of the amygdalohippocampal area. Moderate fiber densities are found in portions of the basal, lateral, and intercalated nuclei. The lowest fiber densities are observed in the accessory basal, posterior cortical, anterior cortical and medial nuclei, and in subregions of the periamygdaloid cortex. The present study provides evidence that the serotonergic system can have substantial influence on the ongoing activity of the amygdaloid complex.
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Affiliation(s)
- M D Bauman
- Department of Psychiatry and Behavioral Sciences, The M.I.N.D. Institute and the California National Primate Research Center, University of California at Davis, Davis, CA 95616, USA
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89
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Heinz A, Braus DF, Smolka MN, Wrase J, Puls I, Hermann D, Klein S, Grüsser SM, Flor H, Schumann G, Mann K, Büchel C. Amygdala-prefrontal coupling depends on a genetic variation of the serotonin transporter. Nat Neurosci 2004; 8:20-1. [PMID: 15592465 DOI: 10.1038/nn1366] [Citation(s) in RCA: 494] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Accepted: 11/05/2004] [Indexed: 11/10/2022]
Abstract
Major depression is conditionally linked to a polymorphism of the human serotonin transporter gene (SLC6A4). During the presentation of aversive, but not pleasant, pictures, healthy carriers of the SLC6A4 short (s) allele showed stronger activation of the amygdala on functional magnetic resonance imaging. s carriers also showed greater coupling between the amygdala and the ventromedial prefrontal cortex, which may contribute to the abnormally high activity in the amygdala and medial prefrontal cortex seen in major depression.
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Affiliation(s)
- Andreas Heinz
- Department of Psychiatry, Charité University Medicine Berlin, Campus Charité Mitte, Schumannstr. 20-21, 10117 Berlin, Germany.
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90
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Abstract
Although eating disorders have been the focus of an unprecedented explosion of clinical interest in recent years, the etiology of anorexia nervosa remains elusive. It is hypothesized that an underlying causative mechanism involves a propensity to extreme fear conditioning and greater than normal resistance to its extinction. Knowledge accrued from recent behavioral, genetic, and neuroanatomic research on anxiety may yield further insight into the pathogenesis of anorexia nervosa, which can be subjected to experimental validation using objective measures of classical fear conditioning and functional neuroimaging of brain structures mediating fear behavior.
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Affiliation(s)
- Michael Strober
- Eating Disorders Program, Department of Psychiatry and Neuropsychiatric Institute and Hospital, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA.
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91
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Furmark T, Tillfors M, Garpenstrand H, Marteinsdottir I, Långström B, Oreland L, Fredrikson M. Serotonin transporter polymorphism related to amygdala excitability and symptom severity in patients with social phobia. Neurosci Lett 2004; 362:189-92. [PMID: 15158011 DOI: 10.1016/j.neulet.2004.02.070] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 01/22/2004] [Accepted: 02/26/2004] [Indexed: 11/18/2022]
Abstract
A functional polymorphism in the promoter region of the human serotonin transporter (5-HTT) gene has been related to negative affect and amygdala activity. We studied amygdala activation during social anxiety provocation in relation to affective ratings and 5-HTT genetic variation. [H2(15)O]positron emission tomography was used to estimate amygdala blood flow during private and public speaking (baseline and anxiety conditions) in 17 patients with social phobia. Genotyping identified patients with long and short alleles in the promoter region of the 5-HTT. Individuals with one or two copies of the short allele exhibited significantly increased levels of anxiety-related traits, state anxiety, and enhanced right amygdala responding to anxiety provocation, compared with subjects homozygous for the long allele. Thus, 5-HTT genetic variation was associated with symptom severity and amygdala excitability in social phobia.
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Affiliation(s)
- Tomas Furmark
- Department of Psychology, Uppsala University, Uppsala, Sweden.
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92
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Suzuki A, Hirota A, Takasawa N, Shigemasu K. Application of the somatic marker hypothesis to individual differences in decision making. Biol Psychol 2003; 65:81-8. [PMID: 14638290 DOI: 10.1016/s0301-0511(03)00093-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The somatic marker hypothesis (Damasio, Tranel, & Damasio, 1991) is a controversial theory asserting that somatic activities implicitly bias human behavior. In this study, we examined the relationship between choice behaviors in the Iowa Gambling Task and patterns of skin conductance responses (SCRs) within a healthy population. Results showed that low SCRs for appraising the monetary outcome of risky decisions were related to persistence in risky choices. Such adherence to risky decisions was not related to poor explicit knowledge about the task. On the other hand, anticipatory SCRs and the effect of them on performance were not confirmed. Our findings suggest that a variation in covert physiological appraisal underlies individual differences in decision making.
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Affiliation(s)
- Atsunobu Suzuki
- Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
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93
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Hariri AR, Weinberger DR. Functional neuroimaging of genetic variation in serotonergic neurotransmission. GENES BRAIN AND BEHAVIOR 2003; 2:341-9. [PMID: 14653306 DOI: 10.1046/j.1601-1848.2003.00048.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) is a potent modulator of the physiology and behavior involved in generating appropriate responses to environmental cues such as danger or threat. Furthermore, genetic variation in 5-HT subsystem genes can impact upon several dimensions of emotional behavior including neuroticism and psychopathology, but especially anxiety traits. Recently, functional neuroimaging has provided a dramatic illustration of how a promoter polymorphism in the human 5-HT transporter (5-HTT) gene, which has been weakly related to these behaviors, is strongly related to the engagement of neural systems, namely the amygdala, subserving emotional processes. In this commentary, we discuss how functional neuroimaging can be used to characterize the effects of polymorphisms in 5-HT subsystem genes on the response of neural circuits underlying the generation and regulation of mood and temperament as well as susceptibility to affective illness. We argue that in time, such knowledge will allow us to not only transcend phenomenological diagnosis and represent mechanisms of disease, but also identify at-risk individuals and biological pathways for the development of new treatments.
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Affiliation(s)
- A R Hariri
- Clinical Brain Disorders Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, US Department of Health and Human Services, Bethesda, Maryland, USA.
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94
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Garpenstrand H, Norton N, Damberg M, Rylander G, Forslund K, Mattila-Evenden M, Gustavsson JP, Ekblom J, Oreland L, Bergman H, Owen MJ, Jönsson EG. A regulatory monoamine oxidase a promoter polymorphism and personality traits. Neuropsychobiology 2003; 46:190-3. [PMID: 12566936 DOI: 10.1159/000067804] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Monoamine oxidase type A (MAOA) has been implicated to be part of mechanisms underlying human temperament and psychiatric disorders. We hypothesised that a functional polymorphism in the 5' untranslated region of the MAOA gene is associated with specific personality traits. In 371 healthy Caucasians, we estimated personality traits by the use of the Karolinska Scales of Personality (KSP), Scandinavian Universities Scales of Personality, Health-Relevant 5-Factor Personality inventory, Temperament and Character Inventory and the revised NEO Personality Inventory. In the same subjects, we analysed the genotype of a polymorphic region consisting of a variable number of a 30-bp repeat sequence located approximately 1.2 kb upstream of the MAOA gene. After correction for multiple testing, no statistically significant differences between MAOA genotype and personality were observed in men (n = 206) nor in women (n = 165). We conclude that the structure of this MAOA promoter region does not have a large impact on the expression of personality characteristics in the present Swedish population.
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95
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Abstract
The recent completion of a working draft of the human genome sequence promises to provide unprecedented opportunities to explore the genetic basis of individual differences in complex behaviours and vulnerability to neuropsychiatric illness. Functional neuroimaging, because of its unique ability to assay information processing at the level of brain within individuals, provides a powerful approach to such functional genomics. Recent fMRI studies have established important physiological links between functional genetic polymorphisms and robust differences in information processing within distinct brain regions and circuits that have been linked to the manifestation of various disease states such as Alzheimer's disease, schizophrenia and anxiety disorders. Importantly, all of these biological relationships have been revealed in relatively small samples of healthy volunteers and in the absence of observable differences at the level of behaviour, underscoring the power of a direct assay of brain physiology like fMRI in exploring the functional impact of genetic variation.
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Affiliation(s)
- Ahmad R Hariri
- Clinical Brain Disorders Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
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96
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Hariri AR, Mattay VS, Tessitore A, Kolachana B, Fera F, Goldman D, Egan MF, Weinberger DR. Serotonin transporter genetic variation and the response of the human amygdala. Science 2002; 297:400-3. [PMID: 12130784 DOI: 10.1126/science.1071829] [Citation(s) in RCA: 1490] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A functional polymorphism in the promoter region of the human serotonin transporter gene (SLC6A4) has been associated with several dimensions of neuroticism and psychopathology, especially anxiety traits, but the predictive value of this genotype against these complex behaviors has been inconsistent. Serotonin [5- hydroxytryptamine, (5-HT)] function influences normal fear as well as pathological anxiety, behaviors critically dependent on the amygdala in animal models and in clinical studies. We now report that individuals with one or two copies of the short allele of the serotonin transporter (5-HTT) promoter polymorphism, which has been associated with reduced 5-HTT expression and function and increased fear and anxiety-related behaviors, exhibit greater amygdala neuronal activity, as assessed by BOLD functional magnetic resonance imaging, in response to fearful stimuli compared with individuals homozygous for the long allele. These results demonstrate genetically driven variation in the response of brain regions underlying human emotional behavior and suggest that differential excitability of the amygdala to emotional stimuli may contribute to the increased fear and anxiety typically associated with the short SLC6A4 allele.
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Affiliation(s)
- Ahmad R Hariri
- Clinical Brain Disorders Branch, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
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