scholarly journals White matter sexual dimorphism of the adult human brain

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Ali K. Bourisly ◽  
Grace Gejo ◽  
Abrar A. Hayat ◽  
Lamya Alsarraf ◽  
Fatima M. Dashti ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
White Matter ◽  
Parietal Lobe ◽  
Brain Regions ◽  
Brain Images ◽  
Brain White Matter ◽  
Significant Difference ◽  
Males And Females ◽  
The Right ◽  
Mri Brain Images

AbstractSex-biased psychophysiology, behavior, brain function, and conditions are extensive, yet underlying structural brain mechanisms remain unclear. There is contradicting evidence regarding sexual dimorphism when it comes to brain structure, and there is still no consensus on whether or not there exists such a dimorphism for brain white matter. Therefore, we conducted a voxel-based morphometry (VBM) analysis along with global volume analysis for white matter across sex. We analyzed 384 T1-weighted MRI brain images (192 male, 192 female) to investigate any differences in white matter (WM) between males and females. In the VBM analysis, we found males to have larger WM, compared to females, in occipital, temporal, insular, parietal, and frontal brain regions. In contrast, females showed only one WM region to be significantly larger than males: the right postcentral gyrus in the parietal lobe region. Although, on average, males showed larger global WM volume, we did not find any significant difference in global WM volume between males and females.

Rats Display Sexual Dimorphism in Phosphorylation of Brain Tau with Age

2021 ◽  
pp. 1-15
Author(s):  
Jiahui Niu ◽  
Khalid Iqbal ◽  
Fei Liu ◽  
Wen Hu
Keyword(s):  
Sexual Dimorphism ◽  
Older Women ◽  
Brain Regions ◽  
Gender Disparity ◽  
Female Rats ◽  
Tau Pathology ◽  
Western Blots ◽  
Total Tau ◽  
Significant Difference ◽  
Males And Females

Background: Women have a two-fold higher risk than men to Alzheimer’s disease (AD) at midlife. Larger brain tau burden was consistently shown in older women than age-matched men. The biological basis for this gender disparity remains elusive. Objective: We sought to know whether tau expression and phosphorylation physiologically differ between males and females. Methods: We used western blots and immunohistochemistry to compare the levels of total tau and phosphorylated tau in the hippocampus and entorhinal cortex (EC) between sexes in Wistar rats at 40 days, and 8 and 20 months of age. Results: We detected no statistically significant difference in total tau, 3R-tau, and 4R-tau between sexes. However, female rats exhibited lower levels of tau unphosphorylated at the Tau-1 site at 40 days of age. At 8 months of age, females showed higher levels of tau phosphorylated at Ser190, Ser387, and Ser395 (Ser199, Ser396, and Ser404 of human tau, respectively) than males in EC. At 20 months of age, both brain regions of female rats consistently showed higher levels than males of tau phosphorylated at Ser253, Ser387, PHF-1 (Ser387/395), and Ser413 sites, which correspond to Ser262, Ser396, Ser396/404, and Ser422 of human tau, respectively. Conclusion: Rats of both sexes have comparable levels of total tau, 3R-tau, and 4R-tau, whereas females exhibit higher levels of tau phosphorylated at multiple sites that are implicated in AD tau pathology, indicating a sexual dimorphism of tau phosphorylation that may potentially underlie the disparity in brain tau burden and risk for AD between sexes.

Neural Underpinnings of Numerical and Spatial Cognition: An fMRI Meta-Analysis of Brain Regions Associated with Symbolic Number, Arithmetic, and Mental Rotation

2019 ◽  
Author(s):  
Zachary Hawes ◽  
H Moriah Sokolowski ◽  
Chuka Bosah Ononye ◽  
Daniel Ansari
Keyword(s):  
Mental Rotation ◽  
Parietal Lobe ◽  
Meta Analysis ◽  
Likelihood Estimation ◽  
Brain Regions ◽  
Angular Gyrus ◽  
Number Representation ◽  
Neural Underpinnings ◽  
The Right ◽  
Symbolic Number

Where and under what conditions do spatial and numerical skills converge and diverge in the brain? To address this question, we conducted a meta-analysis of brain regions associated with basic symbolic number processing, arithmetic, and mental rotation. We used Activation Likelihood Estimation (ALE) to construct quantitative meta-analytic maps synthesizing results from 86 neuroimaging papers (~ 30 studies/cognitive process). All three cognitive processes were found to activate bilateral parietal regions in and around the intraparietal sulcus (IPS); a finding consistent with shared processing accounts. Numerical and arithmetic processing were associated with overlap in the left angular gyrus, whereas mental rotation and arithmetic both showed activity in the middle frontal gyri. These patterns suggest regions of cortex potentially more specialized for symbolic number representation and domain-general mental manipulation, respectively. Additionally, arithmetic was associated with unique activity throughout the fronto-parietal network and mental rotation was associated with unique activity in the right superior parietal lobe. Overall, these results provide new insights into the intersection of numerical and spatial thought in the human brain.

scholarly journals QOL-09. WHOLE-BRAIN WHITE MATTER NETWORK CONNECTIVITY IS DISRUPTED BY PEDIATRIC BRAIN TUMOR TREATMENT

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii432-iii432
Author(s):  
Adeoye Oyefiade ◽  
Kiran Beera ◽  
Iska Moxon-Emre ◽  
Jovanka Skocic ◽  
Ute Bartels ◽  
...  
Keyword(s):  
White Matter ◽  
Pediatric Brain Tumor ◽  
Pediatric Brain Tumors ◽  
Magnetic Resonance Images ◽  
Long Term Effects ◽  
Brain White Matter ◽  
The Right ◽  
Pediatric Brain ◽  
Betweeness Centrality

Abstract INTRODUCTION Treatments for pediatric brain tumors (PBT) are neurotoxic and lead to long-term deficits that are driven by the perturbation of underlying white matter (WM). It is unclear if and how treatment may impair WM connectivity across the entire brain. METHODS Magnetic resonance images from 41 PBT survivors (mean age: 13.19 years, 53% M) and 41 typically developing (TD) children (mean age: 13.32 years, 51% M) were analyzed. Image reconstruction, segmentation, and node parcellation were completed in FreeSurfer. DTI maps and probabilistic streamline generation were completed in MRtrix3. Connectivity matrices were based on the number of streamlines connecting two nodes and the mean DTI (FA) index across streamlines. We used graph theoretical analyses to define structural differences between groups, and random forest (RF) analyses to identify hubs that reliably classify PBT and TD children. RESULTS For survivors treated with radiation, betweeness centrality was greater in the left insular (p < 0.000) but smaller in the right pallidum (p < 0.05). For survivors treated without radiation (surgery-only), betweeness centrality was smaller in the right interparietal sulcus (p < 0.05). RF analyses showed that differences in WM connectivity from the right pallidum to other parts of the brain reliably classified PBT survivors from TD children (classification accuracy = 77%). CONCLUSIONS The left insular, right pallidum, and right inter-parietal sulcus are structurally perturbed hubs in PBT survivors. WM connectivity from the right pallidum is vulnerable to the long-term effects of treatment for PBT.

scholarly journals Multiple sclerosis and depressive manifestations: can diffusion tensor MR imaging help in the detection of microstructural white matter changes?

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Talaat A. Hassan ◽  
Shaima Fattouh Elkholy ◽  
Bahaa Eldin Mahmoud ◽  
Mona ElSherbiny
Keyword(s):  
Multiple Sclerosis ◽  
Depressive Symptoms ◽  
White Matter ◽  
Limbic System ◽  
Diffusion Tensor ◽  
Control Group ◽  
Uncinate Fasciculus ◽  
White Matter Tracts ◽  
Significant Difference ◽  
The Right

Abstract Background Multiple sclerosis is one of the commonest causes of neurological disability in middle-aged and young adults. Depression in MS patients can compromise cognitive functions, lead to suicide attempts, impair relationships and reduce compliance with disease-modifying treatments. The aim of this study was to investigate and compare the microstructural changes in the white matter tracts of the limbic system in MS patients with and those without depressive manifestations using a diffusion tensor imaging (DTI) technique. Methods This study included 40 patients who were divided into three groups. Group 1 comprised of 20 patients with relapsing-remitting MS with depressive symptoms and group 2 comprised 10 MS patients without symptoms of depression. The third group is a control group that included 10 age-matched healthy individuals. All patients underwent conventional MRI examinations and DTI to compare the fractional anisotropy (FA) values in the white matter tracts of the limbic system. Results We compared the DTI findings in MS patients with and those without depressive symptoms. It was found that patients with depression and MS exhibited a significant reduction in the FA values of the cingulum (P < 0.0111 on the right and P < 0.0142 on the left), uncinate fasciculus (P < 0.0001 on the right and P < 0.0076 on the left) and the fornix (P < 0.0001 on both sides). No significant difference was found between the FA values of the anterior thalamic radiations in both groups. Conclusion Patients with depression and MS showed more pronounced microstructural damage in the major white matter connections of the limbic pathway, namely, the uncinate fasciculus, cingulum and fornix. These changes can be detected by DTI as decreased FA values in depressed MS patients compared to those in non-depressed patients.

Early Microstructure Changes of White Matter Fiber Bundles in Patients with Amnestic Mild Cognitive Impairment Predicts Progression of Mild Cognitive Impairment to Alzheimer’s Disease

2021 ◽  
pp. 1-14
Author(s):  
Fangmei He ◽  
Yuchen Zhang ◽  
Xiaofeng Wu ◽  
Youjun Li ◽  
Jie Zhao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Brain Regions ◽  
Amnestic Mild Cognitive Impairment ◽  
Microstructure Changes ◽  
Disease Trajectory ◽  
Development Trajectory ◽  
The Right

Background: Amnestic mild cognitive impairment (aMCI) is the transitional stage between normal aging and Alzheimer’s disease (AD). Some aMCI patients will progress into AD eventually, whereas others will not. If the trajectory of aMCI can be predicted, it would enable early diagnosis and early therapy of AD. Objective: To explore the development trajectory of aMCI patients, we used diffusion tensor imaging to analyze the white matter microstructure changes of patients with different trajectories of aMCI. Methods: We included three groups of subjects:1) aMCI patients who convert to AD (MCI-P); 2) aMCI patients who remain in MCI status (MCI-S); 3) normal controls (NC). We analyzed the fractional anisotropy and mean diffusion rate of brain regions, and we adopted logistic binomial regression model to predicate the development trajectory of aMCI. Results: The fraction anisotropy value is significantly reduced, the mean diffusivity value is significantly increased in the two aMCI patient groups, and the MCI-P patients presented greater changes. Significant changes are mainly located in the cingulum, fornix, hippocampus, and uncinate fasciculus. These changed brain regions significantly correlated with the patient’s Mini-Mental State Examination scores. Conclusion: The study predicted the disease trajectory of different types of aMCI patients based on the characteristic values of the above-mentioned brain regions. The prediction accuracy rate can reach 90.2%, and the microstructure characteristics of the right cingulate band and the right hippocampus may have potential clinical application value to predict the disease trajectory.

scholarly journals MANDIBULAR CANINE INDEX (MCI)

2010 ◽  
Vol 17 (03) ◽  
pp. 459-463
Author(s):  
IRFAN AHMED MUGHAL ◽  
ANWAR SAOOD SAQIB ◽  
FARIDA MANZUR
Keyword(s):  
Medical College ◽  
Significant Difference ◽  
Males And Females ◽  
Mandibular Canine ◽  
Student’S T ◽  
Dental Evidence ◽  
Aseptic Conditions ◽  
Sexual Identification ◽  
The Right ◽  
Mass Disasters

Introduction: Dental evidence is valuable in identification of individuals, especially following mass disasters; estimation of age at death of skeletonised remains and establishing guilt in cases of criminal injury by biting. Mandibular canines are found to exhibit the greatest sexual dimorphism amongst all teeth. Objective: To investigate the accuracy with which gender can be differentiated by using the mandibular canine index in the Punjabi – Pakistani population. Setting: Independent Medical College and Punjab Medical College,  aisalabad. Period: Dec. 2008 to Dec. 2009. Material and Methods: The present study was performed on 200 students, between the age group of 18-25 years, randomly sampled with informed consent (Through 3rd party). Mandibular canine width and intercanine distance were measured with the help of Vernier caliper after observing aseptic conditions. Mandibular canine index was calculated and the observed MCI was compared with the standard MCI value. The data was then analyzed using student’s “t” test. Results: No significant statistical difference was noted between the right and left mandibular canines amongst males and females (same sex) but when comparing between males and females, there was highly statistical significant difference (P < 0.001). The calculated standard MCI for canines of males and females found to be 0.2504. With these calculations we could predict sex correctly at 75.97% in this study (Male: 71.67% and Female: 78.72%). Conclusion: MCI is a quick and reliable method for sexual identification when a standard for the population is available. With these calculations, we could predict the sex correctly at 75.97 % in this study. This method can be used as adjunct to other available tools for sex determination. DNA studies can reveal sex accurately.Availability of comprehensive database with “NADRA” can also be used as adjunct to “MCI” to enhance the accuracy in determination of sex and identity of the person in Pakistan.

Abstract TMP56: Differential Effect of Left versus Right White Matter Hyperintensity Burden on Functional Decline: The Northern Manhattan Study

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Mandip S Dhamoon ◽  
Ying-Kuen Cheung ◽  
Ahmet M Bagci ◽  
Dalila Varela ◽  
Noam Alperin ◽  
...  
Keyword(s):  
White Matter ◽  
Large Population ◽  
Functional Decline ◽  
Frontal Lobes ◽  
White Matter Hyperintensity ◽  
Periventricular White Matter ◽  
Parietal Lobes ◽  
Brain White Matter ◽  
The Right

Background: We previously showed that overall brain white matter hyperintensity volume (WMHV) was associated with accelerated long-term functional decline. Asymmetry of brain dysfunction may disrupt brain network efficiency. We hypothesized that greater left-right WMHV asymmetry was associated with functional trajectories. Methods: In the Northern Manhattan MRI study, participants had brain MRI with axial T1, T2, and fluid attenuated inversion recovery sequences, with baseline interview and examination. Volumetric WMHV distribution across 14 brain regions (brainstem, cerebellum, and bilateral frontal, occipital, temporal, and parietal lobes, and bilateral anterior and posterior periventricular white matter) was determined separately by combining bimodal image intensity distribution and atlas based methods.. Participants had annual functional assessments with the Barthel index (BI, range 0-100) over a mean of 7.3 years. Generalized estimating equations models estimated associations of regional WMHV and regional left-right asymmetry with baseline BI and change over time, adjusted for baseline medical risk factors, sociodemographics, and cognition, and stroke and myocardial infarction during follow-up. Results: Among 1195 participants, mean age was 71 (SD 9) years, 39% were male, 67% had hypertension and 19% diabetes. Greater WMHV asymmetry in the frontal lobes (-3.53 BI points per unit greater WMHV on the right compared to left, 95% CI -0.18, -6.88) and whole brain (-7.23 BI points, 95% CI 0.07, -14.54) was associated with lower overall function. Greater WMHV asymmetry in the frontal lobes (-0.74 additional BI points per year per unit greater WMHV on the right compared to left, 95% CI 0.05, -1.54) and parietal lobes (1.11 additional BI points per year, 95% CI 0.30, 1.93) was independently associated with accelerated functional decline. Periventricular WMHV asymmetry was not associated with function. Conclusions: In this large population-based study with long-term repeated measures of function, greater regional WMHV asymmetry was associated with lower function and functional decline, especially with greater WMHV on the right. In addition to global WMHV, WHMV asymmetry may be an important predictor of long-term functional decline.

On the microstructural origin of brain white matter hydraulic permeability

2021 ◽  
Vol 118 (36) ◽  
pp. e2105328118
Author(s):  
Marco Vidotto ◽  
Andrea Bernardini ◽  
Marco Trovatelli ◽  
Elena De Momi ◽  
Daniele Dini
Keyword(s):  
White Matter ◽  
Corpus Callosum ◽  
Drug Transport ◽  
Three Dimensional ◽  
Principal Component ◽  
Hydraulic Permeability ◽  
Convection Enhanced Delivery ◽  
Brain White Matter ◽  
Significant Difference ◽  
The Brain

Brain microstructure plays a key role in driving the transport of drug molecules directly administered to the brain tissue, as in Convection-Enhanced Delivery procedures. The proposed research analyzes the hydraulic permeability of two white matter (WM) areas (corpus callosum and fornix) whose three-dimensional microstructure was reconstructed starting from the acquisition of electron microscopy images. We cut the two volumes with 20 equally spaced planes distributed along two perpendicular directions, and, on each plane, we computed the corresponding permeability vector. Then, we considered that the WM structure is mainly composed of elongated and parallel axons, and, using a principal component analysis, we defined two principal directions, parallel and perpendicular, with respect to the axons’ main direction. The latter were used to define a reference frame onto which the permeability vectors were projected to finally obtain the permeability along the parallel and perpendicular directions. The results show a statistically significant difference between parallel and perpendicular permeability, with a ratio of about two in both the WM structures analyzed, thus demonstrating their anisotropic behavior. Moreover, we find a significant difference between permeability in corpus callosum and fornix, which suggests that the WM heterogeneity should also be considered when modeling drug transport in the brain. Our findings, which demonstrate and quantify the anisotropic and heterogeneous character of the WM, represent a fundamental contribution not only for drug-delivery modeling, but also for shedding light on the interstitial transport mechanisms in the extracellular space.

The Structural Language Network

2017 ◽  
Author(s):  
Angela D. Friederici ◽  
Noam Chomsky
Keyword(s):  
White Matter ◽  
Language Processing ◽  
Sentence Processing ◽  
Information Transfer ◽  
Right Hemisphere ◽  
Brain Regions ◽  
Neural Basis ◽  
Fiber Tracts ◽  
White Matter Fiber Tracts ◽  
The Right

An adequate description of the neural basis of language processing must consider the entire network both with respect to its structural white matter connections and the functional connectivities between the different brain regions as the information has to be sent between different language-related regions distributed across the temporal and frontal cortex. This chapter discusses the white matter fiber bundles that connect the language-relevant regions. The chapter is broken into three sections. In the first, we look at the white matter fiber tracts connecting the language-relevant regions in the frontal and temporal cortices; in the second, the ventral and dorsal pathways in the right hemisphere that connect temporal and frontal regions; and finally in the third, the two syntax-relevant and (at least) one semantic-relevant neuroanatomically-defined networks that sentence processing is based on. From this discussion, it becomes clear that online language processing requires information transfer via the long-range white matter fiber pathways that connect the language-relevant brain regions within each hemisphere and between hemispheres.

scholarly journals Sense of Agency Beyond Sensorimotor Process: Decoding Self-Other Action Attribution in the Human Brain

2020 ◽  
Vol 30 (7) ◽  
pp. 4076-4091
Author(s):  
Ryu Ohata ◽  
Tomohisa Asai ◽  
Hiroshi Kadota ◽  
Hiroaki Shigemasu ◽  
Kenji Ogawa ◽  
...  
Keyword(s):  
Subjective Experience ◽  
Parietal Lobe ◽  
Neural Substrates ◽  
Brain Regions ◽  
Sense Of Agency ◽  
Posterior Parietal ◽  
Sensorimotor Information ◽  
The One ◽  
The Right ◽  
Different Levels

Abstract The sense of agency is defined as the subjective experience that “I” am the one who is causing the action. Theoretical studies postulate that this subjective experience is developed through multistep processes extending from the sensorimotor to the cognitive level. However, it remains unclear how the brain processes such different levels of information and constitutes the neural substrates for the sense of agency. To answer this question, we combined two strategies: an experimental paradigm, in which self-agency gradually evolves according to sensorimotor experience, and a multivoxel pattern analysis. The combined strategies revealed that the sensorimotor, posterior parietal, anterior insula, and higher visual cortices contained information on self-other attribution during movement. In addition, we investigated whether the found regions showed a preference for self-other attribution or for sensorimotor information. As a result, the right supramarginal gyrus, a portion of the inferior parietal lobe (IPL), was found to be the most sensitive to self-other attribution among the found regions, while the bilateral precentral gyri and left IPL dominantly reflected sensorimotor information. Our results demonstrate that multiple brain regions are involved in the development of the sense of agency and that these show specific preferences for different levels of information.

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