scholarly journals Development of the visual white matter pathways mediates development of electrophysiological responses in visual cortex

2021 ◽  
Author(s):  
Sendy Caffarra ◽  
Sung Jun Joo ◽  
David Bloom ◽  
John Kruper ◽  
Ariel Rokem ◽  
...  
Keyword(s):  
Visual Cortex ◽  
White Matter ◽  
Diffusion Mri ◽  
Developmental Trajectory ◽  
Visual Signals ◽  
Optic Radiation ◽  
High Contrast ◽  
Cross Sectional ◽  
Lower Amplitude ◽  
Optic Radiations

The latency of neural responses in the visual cortex changes systematically across the lifespan. Here we test the hypothesis that development of visual white matter pathways mediates maturational changes in conduction velocities of visual signals. Thirty-eight children participated in a cross-sectional study including diffusion MRI and MEG sessions. During the MEG acquisition, participants performed a lexical decision and a fixation task on words presented at varying levels of contrast and noise. For all stimuli and tasks, early evoked fields were observed around 100 ms after stimulus onset (M100), with slower and lower amplitude responses for low as compared to high contrast stimuli. The optic radiations and optic tracts were identified in each individual's brain based on diffusion MRI tractography. The diffusion properties of the optic radiations predicted M100 responses, especially for high contrast stimuli. Higher optic radiation fractional anisotropy (FA) values were associated with faster and larger M100 responses. Over this developmental window, the M100 responses to high contrast stimuli became faster with age and the optic radiation FA fully mediated this effect. These findings suggest that the maturation of the optic radiations over childhood accounts for individual variations observed in the developmental trajectory of visual cortex responses.

scholarly journals Differential spatial computations in ventral and lateral face-selective regions are scaffolded by structural connections

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dawn Finzi ◽  
Jesse Gomez ◽  
Marisa Nordt ◽  
Alex A. Rezai ◽  
Sonia Poltoratski ◽  
...  
Keyword(s):  
Visual Cortex ◽  
White Matter ◽  
Receptive Field ◽  
Face Processing ◽  
Diffusion Mri ◽  
Lateral Face ◽  
Fine Grain ◽  
Early Visual Cortex ◽  
Structural Connections ◽  
High Level

AbstractFace-processing occurs across ventral and lateral visual streams, which are involved in static and dynamic face perception, respectively. However, the nature of spatial computations across streams is unknown. Using functional MRI and population receptive field (pRF) mapping, we measured pRFs in face-selective regions. Results reveal that spatial computations by pRFs in ventral face-selective regions are concentrated around the center of gaze (fovea), but spatial computations in lateral face-selective regions extend peripherally. Diffusion MRI reveals that these differences are mirrored by a preponderance of white matter connections between ventral face-selective regions and foveal early visual cortex (EVC), while connections with lateral regions are distributed more uniformly across EVC eccentricities. These findings suggest a rethinking of spatial computations in face-selective regions, showing that they vary across ventral and lateral streams, and further propose that spatial computations in high-level regions are scaffolded by the fine-grain pattern of white matter connections from EVC.

scholarly journals Effect of age and neurofibromatosis type 1 status on white matter integrity in the optic radiations

2020 ◽  
Vol 2 (Supplement_1) ◽  
pp. i150-i158
Author(s):  
Peter de Blank ◽  
Jeffrey I Berman ◽  
Marisa Prelack ◽  
John R Sollee ◽  
Adam Lane ◽  
...  
Keyword(s):  
White Matter ◽  
Neurofibromatosis Type 1 ◽  
Normal Values ◽  
Neurofibromatosis Type ◽  
Developmental Trajectory ◽  
White Matter Integrity ◽  
Optic Pathway Glioma ◽  
Optic Radiations ◽  
Effect Of Age

Abstract Background Adults with neurofibromatosis type 1 (NF1) have decreased white matter integrity, but differences in children with NF1 have not been described. Defining normal values for diffusion tensor imaging (DTI) measures, especially in the optic radiations, is important to the development of DTI as a potential biomarker of visual acuity in children with optic pathway glioma. This study examines the effect of age and NF1 status on DTI measures in children. Methods In this retrospective study, MR imaging including DTI was conducted in 93 children (40 children with NF1 and 53 healthy controls) between 0 and 14 years of age. Regression models of age, sex, and NF1 status on DTI measures were evaluated, and tract-based spatial statistics (TBSS) compared DTI measures in age-matched NF1 to non-NF1 cohorts. Results Fractional anisotropy, radial diffusivity, and mean diffusivity in white matter tracts of the optic radiations varied with age and were best modeled by a logarithmic function. Age-related DTI measure change was different in NF1 versus non-NF1 subjects. Normal values and 95% confidence intervals for age 0.5–12 years were derived for both groups. Differences in DTI measures between NF1 and non-NF1 groups at a range of ages were shown diffusely throughout the cerebral white matter using TBSS. Conclusions Children with NF1 demonstrate increased diffusion throughout the brain compared to children without NF1 suggesting a potentially altered developmental trajectory of optic radiation microstructure. Defining normal values for white matter integrity in children with NF1 may help target early intervention efforts in this vulnerable group.

Differential spatial computations in ventral and lateral face-selective regions are scaffolded by structural connections

2020 ◽  
Author(s):  
Dawn Finzi ◽  
Jesse Gomez ◽  
Marisa Nordt ◽  
Alex A. Rezai ◽  
Sonia Poltoratski ◽  
...  
Keyword(s):  
Visual Cortex ◽  
White Matter ◽  
Receptive Field ◽  
Face Processing ◽  
Diffusion Mri ◽  
Lateral Face ◽  
Fine Grain ◽  
Early Visual Cortex ◽  
Structural Connections ◽  
High Level

AbstractFace-processing occurs across ventral and lateral visual streams, which are involved in static and dynamic face perception, respectively. However, the nature of spatial computations across streams is unknown. Using functional MRI and novel population receptive field (pRF) mapping, we measured pRFs in face-selective regions. Results reveal that spatial computations by pRFs in ventral face-selective regions are concentrated around the center of gaze (fovea), but spatial computations in lateral face-selective regions extend peripherally. Diffusion MRI reveals that these differences are mirrored by a preponderance of white matter connections between ventral face-selective regions and foveal early visual cortex (EVC), while connections with lateral regions are distributed more uniformly across EVC eccentricities. These findings suggest a rethinking of spatial computations in face-selective regions, showing that they vary across ventral and lateral streams, and further propose that spatial computations in high-level regions are scaffolded by the fine-grain pattern of white matter connections from EVC.

White matter fiber dissection of the optic radiations of the temporal lobe and implications for surgical approaches to the temporal horn

2004 ◽  
Vol 101 (5) ◽  
pp. 739-746 ◽  
Author(s):  
Eric H. Sincoff ◽  
Yunxi Tan ◽  
Saleem I. Abdulrauf
Keyword(s):  
White Matter ◽  
Temporal Lobe ◽  
Lateral Geniculate Body ◽  
Optic Radiation ◽  
Content Type ◽  
Lateral Geniculate ◽  
Temporal Horn ◽  
Fiber Dissection ◽  
Optic Radiations ◽  
Fine Print

Object. The aim of this anatomical study was to define more fully the three-dimensional (3D) relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe by using the Klingler white matter fiber dissection technique. These findings were correlated with established surgical trajectories to the temporal horn. Such surgical trajectories have implications for amygdalohippocampectomy and other procedures that involve entering the temporal horn for the resection of tumors or vascular lesions. Methods. Ten human cadaveric hemispheres were prepared with several cycles of freezing and thawing by using a modification of the method described by Klingler. Wooden spatulas were used to strip away the deeper layers of white matter progressively in a lateromedial direction, and various association, projection, and commissural fibers were demonstrated. As the dissection progressed, photographs of each progressive layer were obtained. Special attention was given to the optic radiation and to the sagittal stratum of which the optic radiation is a part. The trajectories of fibers in the optic radiation were specifically studied in relation to the lateral, medial, superior, and inferior walls of the temporal horn as well as to the superficial anatomy of the temporal lobe. In three of the hemispheres coronal sections were made so that the relationship between the optic radiation and the temporal horn could be studied more fully. In all 10 hemispheres that were dissected the following observations were made. 1) The optic radiation covered the entire lateral aspect of the temporal horn as it extends to the occipital horn. 2) The anterior tip of the temporal horn was covered by the anterior optic radiation along its lateral half. 3) The entire medial wall of the temporal horn was free from optic radiation fibers, except at the level at which these fibers arise from the lateral geniculate body to ascend over the roof of the temporal horn. 4) The superior wall of the temporal horn was covered by optic radiation fibers. 5) The entire inferior wall of the temporal horn was free from optic radiation fibers anterior to the level of the lateral geniculate body. Conclusions. Fiber dissections of the temporal lobe and horn demonstrated the complex 3D relationships between the optic radiations and the temporal horn and superficial anatomy of the temporal lobe. Based on the results of this study, the authors define two anatomical surgical trajectories to the temporal horn that would avoid the optic radiations. The first of these involves a transsylvian anterior medial approach and the second a pure inferior trajectory through a fusiform gyrus. Lateral approaches to the temporal horn through the superior and middle gyri, based on the authors' findings, would traverse the optic radiations.

From a molar to a molecular approach to the developmental trajectory of syntax comprehension by persons with intellectual disability

2020 ◽  
Author(s):  
Bruno Facon
Keyword(s):  
Developmental Trajectories ◽  
Developmental Trajectory ◽  
Typically Developing ◽  
Cognitive Level ◽  
Cross Sectional ◽  
Test Items ◽  
Complex Sentences ◽  
Regression Curves ◽  
Cognitive Measure ◽  
Syntactic Skills

The aim was to investigate whether a progressive dissociation between the cognitive level and syntax comprehension occurs during the development of persons with intellectual disabilities (ID). Two cross-sectional developmental trajectory analyses were successively conducted. Study 1 comprised 615 typically developing participants and 615 participants with ID. Their total scores on a syntax comprehension test were regressed on a nonverbal cognitive measure and the slopes of the two groups’ regression lines were compared. In Study 2, logistic regression curves of the two groups for each of the 92 test items were compared. Results showed only negligible between-groups differences of developmental trajectories, whatever the level of analysis. The idea of a progressive dissociation between cognitive level and receptive syntactic skills of people with ID is not confirmed. However, a syntax test evaluating more complex sentences than those used in this study might show such a dissociation.

Clustering of short association white matter fibers calculated from diffusion MRI

2014 ◽  
Author(s):  
C. Roman ◽  
D. Le Bihan ◽  
C. Poupon ◽  
P. Guevara ◽  
A. Lebois ◽  
...  
Keyword(s):  
White Matter ◽  
Diffusion Mri

Arterial Stiffness Is Associated with White Matter Disruption and Cognitive Impairment: A Community-Based Cohort Study

2021 ◽  
Vol 80 (2) ◽  
pp. 567-576
Author(s):  
Fei Han ◽  
Fei-Fei Zhai ◽  
Ming-Li Li ◽  
Li-Xin Zhou ◽  
Jun Ni ◽  
...  
Keyword(s):  
Cognitive Function ◽  
White Matter ◽  
Arterial Stiffness ◽  
Cognitive Decline ◽  
Sex Education ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
White Matter Injury ◽  
White Matter Integrity ◽  
Cross Sectional

Background: Mechanisms through which arterial stiffness impacts cognitive function are crucial for devising better strategies to prevent cognitive decline. Objective: To examine the associations of arterial stiffness with white matter integrity and cognition in community dwellings, and to investigate whether white matter injury was the intermediate of the associations between arterial stiffness and cognition. Methods: This study was a cross-sectional analysis on 952 subjects (aged 55.5±9.1 years) who underwent diffusion tensor imaging and measurement of brachial-ankle pulse wave velocity (baPWV). Both linear regression and tract-based spatial statistics were used to investigate the association between baPWV and white matter integrity. The association between baPWV and global cognitive function, measured as the mini-mental state examination (MMSE) was evaluated. Mediation analysis was performed to assess the influence of white matter integrity on the association of baPWV with MMSE. Results: Increased baPWV was significantly associated with lower mean global fractional anisotropy (β= –0.118, p < 0.001), higher mean diffusivity (β= 0.161, p < 0.001), axial diffusivity (β= 0.160, p < 0.001), and radial diffusivity (β= 0.147, p < 0.001) after adjustment of age, sex, and hypertension, which were measures having a direct effect on arterial stiffness and white matter integrity. After adjustment of age, sex, education, apolipoprotein E ɛ4, cardiovascular risk factors, and brain atrophy, we found an association of increased baPWV with worse performance on MMSE (β= –0.093, p = 0.011). White matter disruption partially mediated the effect of baPWV on MMSE. Conclusion: Arterial stiffness is associated with white matter disruption and cognitive decline. Reduced white matter integrity partially explained the effect of arterial stiffness on cognition.

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