6. What do more intelligent brains look like?

2020 ◽  
pp. 83-90
Author(s):  
Ian J. Deary
Keyword(s):  
White Matter ◽  
General Intelligence ◽  
Total Brain Volume ◽  
Brain White Matter ◽  
Total Brain ◽  
Lothian Birth Cohort ◽  
Intelligence Test Scores ◽  
Intelligence Scores ◽  
The Brain ◽  
Brain Connections

‘What do more intelligent brains look like?’ considers a study that used data from the Lothian Birth Cohort 1936 to test the strength of the correlation between the general intelligence scores of the participants and different measures of their brain’s structure. Magnetic resonance imaging was used to measure total brain volume, brain cortical thickness, brain white matter integrity (or health), and brain white matter hyperintensities. The study showed that people who have higher general intelligence tend to have larger brains, thicker grey matter on the surface of the brain, and healthier white matter brain connections. The associations are not strong, but some aspects of brain structure do relate to intelligence test scores.

scholarly journals Brain imaging correlates of general intelligence in UK Biobank

2019 ◽  
Author(s):  
SR Cox ◽  
SJ Ritchie ◽  
C Fawns-Ritchie ◽  
EM Tucker-Drob ◽  
IJ Deary
Keyword(s):  
White Matter ◽  
Brain Structure ◽  
Brain Volume ◽  
Brain Mri ◽  
Cognitive Test ◽  
General Factor ◽  
General Intelligence ◽  
Uk Biobank ◽  
Total Brain Volume ◽  
Total Brain

AbstractThe associations between indices of brain structure and measured intelligence are not clear. In part, this is because the evidence to date comes from mostly small and heterogenous studies. Here, we report brain structure-intelligence associations on a large sample from the UK Biobank study. The overall N = 29,004, with N = 18,363 participants providing both brain MRI and cognitive data, and a minimum N = 7318 providing the MRI data alongside a complete four-test battery. Participants’ age range was 44-81 years (M = 63.13, SD = 7.48). A general factor of intelligence (g) was extracted from four varied cognitive tests, accounting for one third of the variance in the cognitive test scores. The association between (age-and sex-corrected) total brain volume and a latent factor of general intelligence is r = 0.275, 95% C.I. = [0.252, 0.299]. A model that incorporated multiple global measures of grey and white matter macro-and microstructure accounted for more than double the g variance in older participants compared to those in middle-age (13.4% and 5.9%, respectively). There were no sex differences in the magnitude of associations between g and total brain volume or other global aspects of brain structure. The largest brain regional correlates of g were volumes of the insula, frontal, anterior/superior and medial temporal, posterior and paracingulate, lateral occipital cortices, thalamic volume, and the white matter microstructure of thalamic and association fibres, and of the forceps minor.

Cognition, structural brain changes and complicated grief. A population-based study

2014 ◽  
Vol 45 (7) ◽  
pp. 1389-1399 ◽  
Author(s):  
H. C. Saavedra Pérez ◽  
M. A. Ikram ◽  
N. Direk ◽  
H. G. Prigerson ◽  
R. Freak-Poli ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Volume ◽  
Complicated Grief ◽  
Population Based ◽  
Word Fluency ◽  
Total Brain Volume ◽  
Population Based Study ◽  
Total Brain ◽  
Fluency Task ◽  
Structural Brain

BackgroundSeveral psychosocial risk factors for complicated grief have been described. However, the association of complicated grief with cognitive and biological risk factors is unclear. The present study examined whether complicated grief and normal grief are related to cognitive performance or structural brain volumes in a large population-based study.MethodThe present research comprised cross-sectional analyses embedded in the Rotterdam Study. The study included 5501 non-demented persons. Participants were classified as experiencing no grief (n = 4731), normal grief (n = 615) or complicated grief (n = 155) as assessed with the Inventory of Complicated Grief. All persons underwent cognitive testing (Mini-Mental State Examination, Letter–Digit Substitution Test, Stroop Test, Word Fluency Task, word learning test – immediate and delayed recall), and magnetic resonance imaging to measure general brain parameters (white matter, gray matter), and white matter lesions. Total brain volume was defined as the sum of gray matter plus normal white matter and white matter lesion volume. Persons with depressive disorders were excluded and analyses were adjusted for depressive symptoms.ResultsCompared with no-grief participants, participants with complicated grief had lower scores for the Letter–Digit Substitution Test [Z-score −0.16 v. 0.04, 95% confidence interval (CI) −0.36 to −0.04, p = 0.01] and Word Fluency Task (Z-score −0.15 v. 0.03, 95% CI −0.35 to −0.02, p = 0.02) and smaller total volumes of brain matter (933.53 ml v. 952.42 ml, 95% CI −37.6 to −0.10, p = 0.04).ConclusionsParticipants with complicated grief performed poorly in cognitive tests and had a smaller total brain volume. Although the effect sizes were small, these findings suggest that there may be a neurological correlate of complicated grief, but not of normal grief, in the general population.

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.

Microstructural Hyperelastic Characterization of Brain White Matter in Tension

2019 ◽  
Author(s):  
Mohammadreza Ramzanpour ◽  
Mohammad Hosseini-Farid ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Finite Element ◽  
White Matter ◽  
Human Brain ◽  
Volume Fraction ◽  
Fibrous Composite ◽  
Diffuse Axonal Injury ◽  
Stiffness Ratio ◽  
Fibrous Composite Material ◽  
Brain White Matter ◽  
The Brain

Abstract Axons as microstructural constituent elements of brain white matter are highly oriented in extracellular matrix (ECM) in one direction. Therefore, it is possible to model the human brain white matter as a unidirectional fibrous composite material. A micromechanical finite element model of the brain white matter is developed to indirectly measure the brain white matter constituents’ properties including axon and ECM under tensile loading. Experimental tension test on corona radiata conducted by Budday et al. 2017 [1] is used in this study and one-term Ogden hyperelastic constitutive model is applied to characterize its behavior. By the application of genetic algorithm (GA) as a black box optimization method, the Ogden hyperelastic parameters of axon and ECM minimizing the error between numerical finite element simulation and experimental results are measured. Inverse analysis is conducted on the resultant optimized parameters shows high correlation of coefficient (>99%) between the numerical and experimental data which verifies the accuracy of the optimization procedure. The volume fraction of axons in porcine brain white matter is taken to be 52.7% and the stiffness ratio of axon to ECM is perceived to be 3.0. As these values are not accurately known for human brain white matter, we study the material properties of axon and ECM for different stiffness ratio and axon volume fraction values. The results of this study helps to better understand the micromechanical structure of the brain and micro-level injuries such as diffuse axonal injury.

scholarly journals White Matter Dysconnectivity in Panic Disorder with Early Sexual Abuse History: A Preliminary Study

2016 ◽  
Vol 9 (1) ◽  
pp. 128-128
Author(s):  
S. Yu ◽  
◽  
S. Lee
Keyword(s):  
Sexual Abuse ◽  
White Matter ◽  
Panic Disorder ◽  
Childhood Abuse ◽  
Internal Capsule ◽  
Sensitivity Index ◽  
Abuse History ◽  
Brain White Matter ◽  
Preliminary Study ◽  
The Brain

Objective: People who have experienced childhood abuse are more likely to experience frequent or generalized anxiety or panic disorder (PD). Although previous studies have used magnetic resonance imaging (MRI) to demonstrate structural abnormalities of brain in subjects with PD, there are no study about the brain white matter (WM) connectivity differences between PD with and without early sexual abuse. The objective of this study is to compare the brain WM connectivity between PD with and without early sexual abuse history. Design and Method: Twelve right-handed patients with PD [12 women; 35.91±10.29 (mean±SD) age] who met the diagnostic criteria in Structured Clinical Interview for DSM-IV were examined by means of MRI at 3 Tesla. We divided the patients with PD into two groups with and without early sexual abuse to compare the WM connectivity. Panic Disorder Severity Scale (PDSS), Beck Depression Inventory (BDI) and Anxiety Sensitivity Index-Revised (ASI-R) were administered in PD patients. Results: Tract-based spatial statistics showed that fractional anisotropy (FA) values in PD with sexual abuse history were significantly higher than PD without abuse in the right internal capsule, superior corona radiata, sagittal stratum, fornix. The scores of PDSS, BDI, ASI-R were significantly correlated in the above-mentioned WM regions. Conclusions: This preliminary study suggests that early sexual abuse could influence the connectivity among emotion related limbic structures in PD.

scholarly journals Age-specific adult rat brain MRI templates and tissue probability maps

2021 ◽  
Author(s):  
Eilidh MacNicol ◽  
Paul Wright ◽  
Eugene Kim ◽  
Irene Brusini ◽  
Oscar Esteban ◽  
...  
Keyword(s):  
White Matter ◽  
Rat Brain ◽  
Grey Matter ◽  
Brain Volume ◽  
Grey Matter Volume ◽  
Total Brain Volume ◽  
Adult Rat ◽  
Matter Volume ◽  
Probability Maps ◽  
Total Brain

Age-specific resources mitigate biases in human MRI processing arising from structural changes across the lifespan. There are fewer age-specific resources for preclinical imaging, and they only represent developmental periods rather than adulthood. Since rats recapitulate many facets of human aging, it was hypothesized that brain volume and each tissue’s relative contribution to total brain volume would change with age in the adult rat. However, the currently available tissue probability maps, which provide a priori information for tissue volume estimation, provide inaccurate grey matter probabilities in subcortical structures, particularly the thalamus. Consequently, age-specific templates and tissue probability maps were generated from a longitudinal study that scanned a cohort of rats at 3, 5, 11, and 17 months old. Mixed-effects models assessed the effect of age on brain, grey matter, white matter, and CSF volumes, and the relative tissue proportions. Grey and white matter volume increased with age, and the tissue proportions relative to total brain volume varied throughout adulthood. Furthermore, we present evidence of a systematic underestimation of thalamic grey matter volume with existing resources, which is mitigated with the use of age-specific tissue probability maps since the derived estimates better matched histological evidence. To reduce age-related biases in image pre-processing, a set of rat brain resources from across the adult lifespan is consequently released to expand the preclinical MRI community’s fundamental resources.

scholarly journals Spatial Gradient of Microstructural Changes in Normal-Appearing White Matter in Tracts Affected by White Matter Hyperintensities in Older Age

2018 ◽  
Author(s):  
Susana Muñoz Maniega ◽  
Rozanna Meijboom ◽  
Francesca M. Chappell ◽  
Maria C. Valdés Hernández ◽  
John M. Starr ◽  
...  
Keyword(s):  
White Matter ◽  
White Matter Hyperintensities ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Pathological Process ◽  
Spatial Gradient ◽  
Microstructural Changes ◽  
Normal Appearing White Matter ◽  
Brain White Matter ◽  
Lothian Birth Cohort

AbstractBrain white matter hyperintensities (WMH), common in older adults, may contribute to cortical disconnection and cognitive dysfunction. The presence of WMH within white matter (WM) tracts indicates underlying microstructural WM changes that may also affect the normal-appearing WM (NAWM) of a tract. We performed an exploratory study using diffusion magnetic resonance imaging of 52 healthy participants from the Lothian Birth Cohort 1936 (age 72.2 ± 0.7 years) selected to include a range of WMH burden, to quantify microstructural changes of tracts intersecting WMH. We reconstructed tracts using automated tractography and identified intersections with WMH. Tissue volumes and water diffusion tensor parameters (mean diffusivity (MD) and fractional anisotropy (FA)) were established for tract-WMH and tract-NAWM. MD and FA were also measured for tract-NAWM at 2 mm incremental distances from the tract-WMH edge, and from the edge of nearby, non-intersecting, WMH. We observed microstructural changes in tract-WMH suggestive of tissue damage. Tract-NAWM also showed a spatial gradient of FA and MD abnormalities, which diminished with distance from the tract-WMH. Nearby WMH lesions, not directly crossed by the tract, also affected tract microstructure with a similar pattern. Additionally, both FA and MD changes in tract-NAWM were predicted by FA and MD changes respectively in tract-WMH. FA was also predicted by tract-WMH overlap volume, whereas MD was better predicted by whole-brain WMH load. These results suggest that tract-NAWM microstructure is affected by the pathological process underlying WMH, when WMH are either within or near to the tract. The changes in NAWM tract tissue may indicate future lesion progression and may play an important role in cognitive ageing.

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