scholarly journals Interhemispheric Relationship of Genetic Influence on Human Brain Connectivity

2020 ◽  
Vol 31 (1) ◽  
pp. 77-88
Author(s):  
Suyu Zhong ◽  
Long Wei ◽  
Chenxi Zhao ◽  
Liyuan Yang ◽  
Zengru Di ◽  
...  
Keyword(s):  
Human Brain ◽  
Genetic Correlation ◽  
Genetic Factors ◽  
Brain Connectivity ◽  
Genetic Correlations ◽  
Disease States ◽  
Left And Right ◽  
Genetically Determined ◽  
Relationship Of ◽  
Insight Into

Abstract To understand the origins of interhemispheric differences and commonalities/coupling in human brain wiring, it is crucial to determine how homologous interregional connectivities of the left and right hemispheres are genetically determined and related. To address this, in the present study, we analyzed human twin and pedigree samples with high-quality diffusion magnetic resonance imaging tractography and estimated the heritability and genetic correlation of homologous left and right white matter (WM) connections. The results showed that the heritability of WM connectivity was similar and coupled between the 2 hemispheres and that the degree of overlap in genetic factors underlying homologous WM connectivity (i.e., interhemispheric genetic correlation) varied substantially across the human brain: from complete overlap to complete nonoverlap. Particularly, the heritability was significantly stronger and the chance of interhemispheric complete overlap in genetic factors was higher in subcortical WM connections than in cortical WM connections. In addition, the heritability and interhemispheric genetic correlations were stronger for long-range connections than for short-range connections. These findings highlight the determinants of the genetics underlying WM connectivity and its interhemispheric relationships, and provide insight into genetic basis of WM connectivity asymmetries in both healthy and disease states.

scholarly journals Genetic correlations across genetically determined and developmentally plastic alternative reproductive tactics

2019 ◽  
Author(s):  
Jessica K. Abbott ◽  
Oscar Rios-Cardenas ◽  
Molly Morris
Keyword(s):  
Body Size ◽  
Genetic Correlation ◽  
Genetic Correlations ◽  
Phenotypic Expression ◽  
Alternative Reproductive Tactics ◽  
Phenotypic Trait ◽  
Sexual Antagonism ◽  
Reproductive Tactics ◽  
Genetic Conflict ◽  
Genetically Determined

AbstractAlternative reproductive tactics occur when individuals of the same sex have a suite of morphological and/or behavioural traits that allow them to pursue different reproductive strategies. A common pattern is e.g. the existence of “courter” and “sneaker” tactics within males. We have previously argued that alternative reproductive tactics should be subject to genetic conflict over the phenotypic expression of traits, similar to sexual antagonism. In this process, which we called intra-locus tactical conflict, genetically determined tactics experience conflicting selection on a shared phenotypic trait, such as body size, but a positive genetic correlation between tactics in body size prevents either tactic from reaching its optimum. Recently, other authors have attempted to extend this idea to developmentally plastic alternative reproductive tactics, with mixed results. However, it is not clear whether we should expect intra-locus tactical conflict in developmentally plastic tactics or not. We have therefore run a series of simulation models investigating under what conditions we should expect to see positive estimates of the inter-tactical genetic correlation, since a positive genetic correlation is a prerequisite for the existence of intra-locus tactical conflict. We found that for autosomal, X-linked, and Y-linked genetically-determined tactics, estimated inter-tactical genetic correlations were generally high. However, for developmentally plastic tactics, the genetic correlation depends on the properties of the switching threshold between tactics. If it is fixed, then estimated genetic correlations are positive, but if there is genetic variation in the switch-point, then any sign and magnitude of estimated genetic correlation is possible, even for highly heritable traits where the true underlying correlation is perfect. This means that caution should be used when investigating genetic constraints in plastic phenotypes.

scholarly journals The functional relationship of the interleukins.

1980 ◽  
Vol 151 (6) ◽  
pp. 1551-1556 ◽  
Author(s):  
K A Smith ◽  
L B Lachman ◽  
J J Oppenheim ◽  
M F Favata
Keyword(s):  
T Cell ◽  
Functional Relationship ◽  
Immunosuppressive Agents ◽  
Therapeutic Approaches ◽  
Disease States ◽  
New Therapeutic Approaches ◽  
Relationship Of ◽  
Insight Into ◽  
T Cell Growth Factor ◽  
Stimulation Of

The mechanism of the lymphoproliferative effect of the macrophage product lymphocyte-activating factor [LAF(IL1] appears to be mediated by the stimulation of the release of T cell growth factor [TCGF(IL2)] by T cells. The magnitude of the resultant T cell proliferative clonal expansion is thus dependent upon the quantity of both LAF(IL1) and TCGF(IL2) induced by antigen or lectin stimulation. These observations, coupled with the ability to measure the production and actions of these hormone-like lymphokines, should allow for increased insight into the mode of action of immunoenhancing and immunosuppressive agents, as well as for new therapeutic approaches to disease states involving T lymphocytes.

scholarly journals Investigating the source of increased bipolar and major depressive disorder polygenic risk in multiplex schizophrenia families

2021 ◽  
Author(s):  
Mohammad Ahangari ◽  
Robert Kirkpatrick ◽  
Tan-Hoang Nguyen ◽  
Nathan Gillespie ◽  
Irish Schizophrenia Genomics Consortium ◽  
...  
Keyword(s):  
Major Depressive Disorder ◽  
Depressive Disorder ◽  
Psychiatric Disorders ◽  
Genetic Correlation ◽  
Affective Disorders ◽  
Genetic Factors ◽  
Genetic Correlations ◽  
Polygenic Risk Score ◽  
Major Depressive ◽  
Polygenic Risk

Psychotic and affective disorders often aggregate in the relatives of probands with schizophrenia (SCZ), and genetic studies show substantial genetic correlation among SCZ, bipolar disorder (BIP) and major depressive disorder (MDD). However, the nature of this genetic overlap in polygenic risk score (PRS) analyses of multiplex families has not been fully dissected. In the current study, we investigated the polygenic risk burden of BIP and MDD in a sample of 257 multiplex SCZ families (N=1,005) and population controls (N=2,205). Furthermore, due to the strong genetic correlation among SCZ, BIP, and MDD, we examined whether increased BIP or MDD PRS in members of multiplex SCZ families can be attributed to latent genetic factors unique to BIP or MDD, or latent genetic factors that each of these two disorders share with SCZ. Our results indicate that members of multiplex SCZ families have an increased PRS for BIP and MDD, however, this observation is largely attributable to latent genetic factors that BIP or MDD share with SCZ, rather than latent genetic factors unique to them. These results provide new insight for cross-disorder PRS analyses of psychiatric disorders, by cautioning that for complete interpretation of observed cross-disorder PRS enrichment, we should account for genetic correlations across psychiatric disorders. Our findings further indicates that members of multiplex SCZ families may have an increased genetic vulnerability to both psychotic and affective disorders, and for full assessment of an individual genetic risk, familial backgrounds should be taken into consideration.

scholarly journals Gambling, disordered gambling and their association with major depression and substance use: a web-based cohort and twin-sibling study

2011 ◽  
Vol 42 (3) ◽  
pp. 497-508 ◽  
Author(s):  
C. Blanco ◽  
J. Myers ◽  
K. S. Kendler
Keyword(s):  
Major Depression ◽  
Genetic Factors ◽  
Genetic Correlations ◽  
Caffeine Intake ◽  
Disordered Gambling ◽  
Web Based ◽  
Entire Cohort ◽  
Sibling Pairs ◽  
Latent Dimension ◽  
Genetically Determined

BackgroundRelatively little is known about the environmental and genetic contributions to gambling frequency and disordered gambling (DG), the full continuum of gambling-related problems that includes pathological gambling (PG).MethodA web-based sample (n=43 799 including both members of 609 twin and 303 sibling pairs) completed assessments of number of lifetime gambling episodes, DSM-IV criteria for PG, alcohol, nicotine and caffeine intake, and nicotine dependence (ND) and DSM-III-R criteria for lifetime major depression (MD). Twin modeling was performed using Mx.ResultsIn the entire cohort, symptoms of DG indexed a single dimension of liability. Symptoms of DG were weakly related to caffeine intake and moderately related to MD, consumption of cigarettes and alcohol, and ND. In twin and sibling pairs, familial resemblance for number of times gambled resulted from both familial–environmental (c2=42%) and genetic factors (a2=32%). For symptoms of DG, resemblance resulted solely from genetic factors (a2=83%). Bivariate analyses indicated a low genetic correlation between symptoms of DG and MD (ra=+0.14) whereas genetic correlations with DG symptoms were substantially higher with use of alcohol, caffeine and nicotine, and ND (ranging from +0.29 to +0.80). The results were invariant across genders.ConclusionsWhereas gambling participation is determined by shared environmental and genetic factors, DG constitutes a single latent dimension that is largely genetically determined and more closely related to externalizing than internalizing behaviors. Because these findings are invariant across genders, they suggest that the etiological factors of DG are likely to be similar in men and women.

scholarly journals Conceptual and Data-based Investigation of Genetic Influences and Brain Asymmetry: A Twin Study of Multiple Structural Phenotypes

2014 ◽  
Vol 26 (5) ◽  
pp. 1100-1117 ◽  
Author(s):  
Lisa T. Eyler ◽  
Eero Vuoksimaa ◽  
Matthew S. Panizzon ◽  
Christine Fennema-Notestine ◽  
Michael C. Neale ◽  
...  
Keyword(s):  
Twin Study ◽  
Genetic Factors ◽  
Right Hemisphere ◽  
Genetic Correlations ◽  
Monozygotic Twin ◽  
Genetic Influences ◽  
Size Difference ◽  
Subcortical Structures ◽  
Structural Asymmetry ◽  
Left And Right

Right–left regional cerebral differences are a feature of the human brain linked to functional abilities, aging, and neurodevelopmental and mental disorders. The role of genetic factors in structural asymmetry has been incompletely studied. We analyzed data from 515 individuals (130 monozygotic twin pairs, 97 dizygotic pairs, and 61 unpaired twins) from the Vietnam Era Twin Study of Aging to answer three questions about genetic determinants of brain structural asymmetry: First, does the magnitude of heritability differ for homologous regions in each hemisphere? Despite adequate power to detect regional differences, heritability estimates were not significantly larger in one hemisphere versus the other, except left > right inferior lateral ventricle heritability. Second, do different genetic factors influence left and right hemisphere size in homologous regions? Interhemispheric genetic correlations were high and significant; in only two subcortical regions (pallidum and accumbens) did the estimate statistically differ from 1.0. Thus, there was little evidence for different genetic influences on left and right hemisphere regions. Third, to what extent do genetic factors influence variability in left–right size differences? There was no evidence that variation in asymmetry (i.e., the size difference) of left and right homologous regions was genetically determined, except in pallidum and accumbens. Our findings suggest that genetic factors do not play a significant role in determining individual variation in the degree of regional cortical size asymmetries measured with MRI, although they may do so for volume of some subcortical structures. Despite varying interpretations of existing data, we view the present results as consistent with previous findings.

TMS and positron emission tomography: methods and current advances

2012 ◽  
Author(s):  
Hartwig R. Siebner ◽  
Martin Peller ◽  
Lucy Lee
Keyword(s):  
Positron Emission Tomography ◽  
Human Brain ◽  
Brain Function ◽  
Normal Activity ◽  
Emission Tomography ◽  
Sources Of Information ◽  
Disease States ◽  
Positron Emission ◽  
Different Sources ◽  
Insight Into

This article provides an overview of how transcranial magnetic stimulation (TMS) and positron emission tomography (PET) can be combined. It explains the methodology concerning the combination of TMS with PET and discusses the applications of this combination to study human brain function. TMS represents a nonphysiological means of producing or modulating neuronal activity in the human brain. PET imaging can make an important contribution to the understanding of the mechanisms of action of repetitive TMS and has the potential to determine neural correlates of compensatory plasticity in both healthy subjects and disease states. By using different sources of information, the TMS-PET approach provides insight into the neurophysiological effects of TMS on human brain function. The future use of TMS is to improve the understanding of how the nonphysiological mode of brain stimulation interacts with ‘normal’ activity in the human brain.

scholarly journals Shared Genetic Factors Underlie Migraine and Depression

2016 ◽  
Vol 19 (4) ◽  
pp. 341-350 ◽  
Author(s):  
Yuanhao Yang ◽  
Huiying Zhao ◽  
Andrew C. Heath ◽  
Pamela A. F. Madden ◽  
Nicholas G. Martin ◽  
...  
Keyword(s):  
Depressive Disorder ◽  
Genetic Correlation ◽  
Genetic Factors ◽  
International Headache Society ◽  
Diagnostic Measures ◽  
Diagnostic And Statistical Manual ◽  
Twin Models ◽  
Id Migraine ◽  
Genetically Determined ◽  
Shared Genetic

Migraine frequently co-occurs with depression. Using a large sample of Australian twin pairs, we aimed to characterize the extent to which shared genetic factors underlie these two disorders. Migraine was classified using three diagnostic measures, including self-reported migraine, the ID migraine™ screening tool, or migraine without aura (MO) and migraine with aura (MA) based on International Headache Society (IHS) diagnostic criteria. Major depressive disorder (MDD) and minor depressive disorder (MiDD) were classified using the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria. Univariate and bivariate twin models, with and without sex-limitation, were constructed to estimate the univariate and bivariate variance components and genetic correlation for migraine and depression. The univariate heritability of broad migraine (self-reported, ID migraine, or IHS MO/MA) and broad depression (MiDD or MDD) was estimated at 56% (95% confidence interval [CI]: 53–60%) and 42% (95% CI: 37–46%), respectively. A significant additive genetic correlation (rG = 0.36, 95% CI: 0.29–0.43) and bivariate heritability (h2 = 5.5%, 95% CI: 3.6–7.8%) was observed between broad migraine and depression using the bivariate Cholesky model. Notably, both the bivariate h2 (13.3%, 95% CI: 7.0–24.5%) and rG (0.51, 95% CI: 0.37–0.69) estimates significantly increased when analyzing the more narrow clinically accepted diagnoses of IHS MO/MA and MDD. Our results indicate that for both broad and narrow definitions, the observed comorbidity between migraine and depression can be explained almost entirely by shared underlying genetically determined disease mechanisms.

Transgenerational inheritance of non-genetically determined phenotypes

2013 ◽  
Vol 41 (3) ◽  
pp. 769-776 ◽  
Author(s):  
Michelle L. Holland ◽  
Vardhman K. Rakyan
Keyword(s):  
Environmental History ◽  
Molecular Mechanisms ◽  
Genetic Factors ◽  
Developmental Outcome ◽  
Transgenerational Inheritance ◽  
The Core ◽  
Genetically Determined ◽  
Core Issues ◽  
Insight Into ◽  
Molecular Nature

Inheritance of non-genetic factors permits ancestral environmental history to inform the development of subsequent generations. This form of soft inheritance has been shown in mammals, yet the molecular underpinnings of this phenomenon are poorly understood. In the present article, we focus on gametic inheritance of non-genetic factors, utilizing examples of paternal transmission to explore the core issues that need to be addressed in order to gain greater insight into the molecular mechanisms. Three essential processes are identified: (i) how the environment affects the germline to establish an altered molecular milieu, (ii) the molecular nature of the inherited mark, and (iii) how this affects genome function in the developing embryo to elicit an alternative developmental outcome.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

The crystallography characteristic of (Mn,Fe)S single crystal

1990 ◽  
Vol 48 (4) ◽  
pp. 898-899
Author(s):  
Jiang Xishan
Keyword(s):  
Single Crystal ◽  
Cast Steel ◽  
Point Group ◽  
Central Area ◽  
Hexagonal Crystal ◽  
Growth Step ◽  
Left And Right ◽  
Relationship Of ◽  
Fcc Structure ◽  
New Discovery

This paper reports the growth step pattern and morphology at equilibrium and growth states of (Mn,Fe)S single crystal on the wall of micro-voids in ZG25 cast steel by using scanning electron microscope. Seldom report was presented on the growth morphology and steppattern of (Mn,Fe)S single crystal.Fig.1 shows the front half of the polyhedron of(Mn,Fe)S single crystal,its central area being the square crystal plane,the two pairs of hexagons symmetrically located in the high and low, the left and right with a certain, angle to the square crystal plane.According to the symmetrical relationship of crystal, it was defined that the (Mn,Fe)S single crystal at equilibrium state is tetrakaidecahedron consisted of eight hexagonal crystal planes and six square crystal planes. The macroscopic symmetry elements of the tetrakaidecahedron correpond to Oh—n3m symmetry class of fcc structure,in which the hexagonal crystal planes are the { 111 } crystal planes group,square crystal plaits are the { 100 } crystal planes group. This new discovery of the (Mn,Fe)S single crystal provides a typical example of the point group of Oh—n3m.

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