scholarly journals 3. On a Case of Absence of the Corpus Callosum in the Human Brain

1889 ◽  
Vol 15 ◽  
pp. 320-341 ◽  
Author(s):  
Alexander Bruce
Keyword(s):  
Corpus Callosum ◽  
Human Brain ◽  
Cerebral Hemispheres

Cases of absence or defect of the corpus callosum are of interest not only because of their great rarity, but because of the light which they throw on the distribution and functions of this commissure, and on the development of the mesial aspects of the cerebral hemispheres.

Analysis of 3D Corpus Callosum Images in the Brains of Autistic Individuals

2016 ◽  
pp. 159-184
Author(s):  
Ahmed Elnakib ◽  
Manuel F. Casanova ◽  
Ahmed Soliman ◽  
Georgy Gimel'farb ◽  
Ayman El-Baz
Keyword(s):  
Autism Spectrum Disorder ◽  
Corpus Callosum ◽  
Human Brain ◽  
Shape Analysis ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Cerebral Hemispheres ◽  
Higher Cognitive Functions ◽  
The Right ◽  
Abnormal Anatomy

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is characterized by abnormalities in behavior and higher cognitive functions. The corpus callosum (CC) is the largest fiber bundle that connects the left and the right cerebral hemispheres of the human brain. Several studies have revealed an abnormal anatomy of the CC in the brains of autistic individuals that associates this neurodevelopmental condition with impaired communication between the hemispheres. In this chapter, we develop a framework to analyze the CC of autistic individuals in order to provide a diagnostic tool for autism. The key advantage of this approach is the development of a cylindrical mapping that offers simplified coordinates for comparing the brains of autistic individuals and neurotypicals. Experimental results showed significant differences (at the 95% confidence level) between 17 normal and 17 autistic subjects in four anatomical divisions, i.e. splenium, rostrum, genu, and body of their CCs. Moreover, the initial centerline-based shape analysis of the CC documented a promising supplement to the current techniques for diagnosing autism.

III. On the commissures of the cerebral hemispheres of the marsupialia and monotremata, as compared with those of the placental mammals

1865 ◽  
Vol 14 ◽  
pp. 71-74 ◽  
Keyword(s):  
Corpus Callosum ◽  
Human Brain ◽  
Human Body ◽  
Short Description ◽  
Cerebral Hemispheres ◽  
Middle Line ◽  
Short Space ◽  
Mutual Relations ◽  
Superior Margin

As it is most convenient to pass from the best to the least known, and especially as the terms used in describing the anatomy of the vertebrated animals have in most cases been originally bestowed upon parts of the human body, the Paper commences by a short description of the septum ventriculorum and commissures of the human brain. This is done with a view to establish clearly, both by their structure and development, the mutual relations of the great transverse commissure or corpus callosum and the fornix. The latter is defined as essentially a longitudinal commissure, consisting of two lateral halves closely applied for a short space in the middle line, but each half belonging to its own hemisphere, and formed out of the longitudinal fibres bordering the superior margin of the ventricular aperture.

Self-Consciousness and "Split" Brains

2018 ◽  
Author(s):  
Elizabeth Schechter
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Corpus Callosum ◽  
Human Brain ◽  
The United States ◽  
The Other ◽  
Cerebral Hemispheres ◽  
Experimental Conditions ◽  
Fiber Tract ◽  
Split Brain

The largest fiber tract in the human brain is the corpus callosum, which connects the two cerebral hemispheres. A number of surgeries severing this structure were performed on adults in the United States in the second half of the twentieth century. After they are surgically separated from each other in this way, a “split-brain” subject’s hemispheres begin to operate unusually independently of each other in the realms of perception, cognition, and the control of action—almost as if each had a mind of its own. But can a mere hemisphere really see? Speak? Feel? Know what it has done? The split-brain cases raise questions of psychological identity: How many subjects of experience are there within a split-brain subject? How many persons? How many minds? Under experimental conditions, split-brain subjects often act as though they were animated by two distinct conscious beings, evoking the duality intuition. On the other hand, a split-brain subject seems like one of us—not like two of us sharing one body. Split-brain subjects thus also evoke the unity intuition.This book is devoted to reconciling these two apparently opposing intuitions. The key to doing so are facts about the way self-consciousness operates in split-brain subjects. A split-brain subject is composed of two conscious psychological beings that fail to recognize each other’s existence and indeed cannot distinguish themselves from each other. Instead, each must first-personally identify with the split-brain subject as a whole, and in so doing, the two make themselves into one person.

Analysis of 3D Corpus Callosum Images in the Brains of Autistic Individuals

2016 ◽  
pp. 1529-1554
Author(s):  
Ahmed Elnakib ◽  
Manuel F. Casanova ◽  
Ahmed Soliman ◽  
Georgy Gimel'farb ◽  
Ayman El-Baz
Keyword(s):  
Autism Spectrum Disorder ◽  
Corpus Callosum ◽  
Human Brain ◽  
Shape Analysis ◽  
Neurodevelopmental Disorder ◽  
Autism Spectrum ◽  
Cerebral Hemispheres ◽  
Higher Cognitive Functions ◽  
The Right ◽  
Abnormal Anatomy

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is characterized by abnormalities in behavior and higher cognitive functions. The corpus callosum (CC) is the largest fiber bundle that connects the left and the right cerebral hemispheres of the human brain. Several studies have revealed an abnormal anatomy of the CC in the brains of autistic individuals that associates this neurodevelopmental condition with impaired communication between the hemispheres. In this chapter, we develop a framework to analyze the CC of autistic individuals in order to provide a diagnostic tool for autism. The key advantage of this approach is the development of a cylindrical mapping that offers simplified coordinates for comparing the brains of autistic individuals and neurotypicals. Experimental results showed significant differences (at the 95% confidence level) between 17 normal and 17 autistic subjects in four anatomical divisions, i.e. splenium, rostrum, genu, and body of their CCs. Moreover, the initial centerline-based shape analysis of the CC documented a promising supplement to the current techniques for diagnosing autism.

scholarly journals Encephalometry on the medial face of the human brain hemisphere: a necropsy study

2005 ◽  
Vol 63 (2b) ◽  
pp. 430-436 ◽  
Author(s):  
Paula J. Ribeiro ◽  
Serafim V. Cricenti V. ◽  
Carmen L.P. Lancellotti
Keyword(s):  
Corpus Callosum ◽  
Human Brain ◽  
Frontal Cortex ◽  
Anterior Part ◽  
Average Distance ◽  
Posterior Part ◽  
Cerebral Hemispheres ◽  
Frontal Pole ◽  
Occipital Pole ◽  
The Right

This study aims to evaluate the dimensions of the human brain, specifically in the frontal cortex, helping the analysis of neuroimaging. A form was made to register and describe encephalic measurements and 81 cerebral hemispheres (CH) were analyzed. Male individuals showed larger CH length; wider superior frontal gyrus in the right CH; bigger encephalic weight and corpus callosum (CC) width. The proportion of measurement from the frontal pole to the most anterior part of the CC genu, related to the CH length gets smaller with aging, whereas the average distance from the most posterior part of the splenum of the CC to the occipital pole was bigger in both male CHs and there was a tendency of decrease in this difference with aging.

scholarly journals Non-local means based Rician noise filtering for diffusion tensor and kurtosis imaging in human brain and spinal cord

2020 ◽  
Author(s):  
Zhongping Zhang ◽  
Dhanashree Vernekar ◽  
Wenshu Qian ◽  
Mina Kim
Keyword(s):  
Spinal Cord ◽  
Corpus Callosum ◽  
Human Brain ◽  
Healthy Subjects ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Chi Square ◽  
Lateral Column ◽  
Diffusion Weighted Images ◽  
The Brain

Abstract Background: To investigate the effect of using an Rician nonlocal means (NLM) filter on quantification of diffusion tensor (DT)- and diffusion kurtosis (DK)-derived metrics in various anatomical regions of the human brain and the spinal cord, when combined with a constrained linear least squares (CLLS) approach.Methods: Prospective brain data from 9 healthy subjects and retrospective spinal cord data from 5 healthy subjects from a 3T MRI scanner were included in the study. Prior to tensor estimation, registered diffusion weighted images were denoised by an optimized blockwise NLM filter with CLLS. Mean kurtosis (MK), radial kurtosis (RK), axial kurtosis (AK), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD) and fractional anisotropy (FA), were determined in anatomical structures of the brain and the spinal cord. DTI and DKI metrics, signal-to-noise ratio (SNR) and Chi-square values were quantified in distinct anatomical regions for all subjects, with and without Rician denoising. Results: The averaged SNR significantly increased with Rician denoising by a factor of 2 while the averaged Chi-square values significantly decreased up to 61 % in the brain and up to 43% in the spinal cord after Rician NLM filtering. In the brain, the mean MK varied from 0.70 (putamen) to 1.27 (internal capsule) while AK and RK varied from 0.58 (corpus callosum) to 0.92 (cingulum) and from 0.70 (putamen) to 1.98 (corpus callosum), respectively. In the spinal cord, FA varied from 0.78 in lateral column to 0.81 in dorsal column while MD varied from 0.91 × 10−3 mm2/s (lateral) to 0.93 × 10−3 mm2/s (dorsal). RD varied from 0.34 × 10−3 mm2/s (dorsal) to 0.38 × 10−3 mm2/s (lateral) and AD varied from 1.96 × 10−3 mm2/s (lateral) to 2.11 × 10−3 mm2/s (dorsal).Conclusions: Our results show Rician denoising NLM filter incorporated with CLLS significantly increases SNR and reduces estimation errors of DT- and KT-derived metrics, providing the reliable metrics estimation with adequate SNR levels.

scholarly journals Human brain harbors single nucleotide somatic variations in functionally relevant genes possibly mediated by oxidative stress

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 2520 ◽  
Author(s):  
Anchal Sharma ◽  
Asgar Hussain Ansari ◽  
Renu Kumari ◽  
Rajesh Pandey ◽  
Rakhshinda Rehman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Corpus Callosum ◽  
Human Brain ◽  
Frontal Cortex ◽  
Oxidative Stress Marker ◽  
Somatic Variation ◽  
Single Nucleotide ◽  
Normal Human Brain ◽  
Normal Human ◽  
The Brain

Somatic variation in DNA can cause cells to deviate from the preordained genomic path in both disease and healthy conditions. Here, using exome sequencing of paired tissue samples, we show that the normal human brain harbors somatic single base variations measuring up to 0.48% of the total variations. Interestingly, about 64% of these somatic variations in the brain are expected to lead to non-synonymous changes, and as much as 87% of these represent G:C>T:A transversion events. Further, the transversion events in the brain were mostly found in the frontal cortex, whereas the corpus callosum from the same individuals harbors the reference genotype. We found a significantly higher amount of 8-OHdG (oxidative stress marker) in the frontal cortex compared to the corpus callosum of the same subjects (p<0.01), correlating with the higher G:C>T:A transversions in the cortex. We found significant enrichment for axon guidance and related pathways for genes harbouring somatic variations. This could represent either a directed selection of genetic variations in these pathways or increased susceptibility of some loci towards oxidative stress. This study highlights that oxidative stress possibly influence single nucleotide somatic variations in normal human brain.

scholarly journals Determination of Vitamin D and Its Metabolites in Human Brain Using an Ultra-Pressure LC–Tandem Mass Spectra Method

2019 ◽  
Vol 3 (7) ◽  
Author(s):  
Xueyan Fu ◽  
Gregory G Dolnikowski ◽  
William B Patterson ◽  
Bess Dawson-Hughes ◽  
Tong Zheng ◽  
...  
Keyword(s):  
Vitamin D ◽  
Corpus Callosum ◽  
Human Brain ◽  
Vitamin D3 ◽  
Temporal Cortex ◽  
National Development ◽  
Brain Regions ◽  
Accurate Information ◽  
Vitamin D Metabolites

ABSTRACTBackgroundLow serum total 25-hydroxyvitamin D3 [25(OH)D3] concentrations have been associated with cognitive impairment. However, it is unclear if serum 25(OH)D3 concentrations are a valid indicator of the concentrations of vitamin D and its metabolites in human brain.ObjectivesThe aim of this study was to develop and validate a method to quantify vitamin D3, 25(OH)D3, and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in human brain.MethodsThe assay developments were performed using porcine brains. Liquid extraction was used in homogenized samples (∼0.1 g each) prior to analysis by LC-MS/MS with electrospray ionization following derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione. This method was then applied to the determination of vitamin D and its metabolites in a whole human brain obtained from the National Development and Research Institutes.ResultsThe method showed good linearity of vitamin D3, 25(OH)D3, and 1,25(OH)2D3 over the physiological range (R2 = 0.9995, 0.9968, and 0.9970, respectively). The lowest detection limit for vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in porcine brain was 25, 50 and 25 pg/g, respectively. The method was successfully applied to the determination of vitamin D3 and its metabolites in the prefrontal cortex, middle frontal cortex, middle temporal cortex, cerebellum, corpus callosum, medulla, and pons of a human brain. All analyzed human brain regions contained 25(OH)D3, with corpus callosum containing 334 pg/g compared with 158 pg/g in cerebellum. 1,25(OH)2D3 was only detected in prefrontal and middle frontal cortices at a very low level. No vitamin D3 was detected in any examined areas of this single human brain.ConclusionsTo the best of our knowledge, this study is the first report of the measurement of concentrations of vitamin D metabolites in human brain. This validated method can be applied to postmortem studies to obtain accurate information about the presence and role of vitamin D and its metabolites in human brain and neurodegenerative diseases.

scholarly journals Interhemispheric functional disconnection because of abnormal corpus callosum integrity in bipolar disorder type II

BJPsych Open ◽  
2016 ◽  
Vol 2 (6) ◽  
pp. 335-340 ◽  
Author(s):  
Fumihiko Yasuno ◽  
Takashi Kudo ◽  
Kiwamu Matsuoka ◽  
Akihide Yamamoto ◽  
Masato Takahashi ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Corpus Callosum ◽  
Emotional Dysregulation ◽  
Cerebral Hemispheres ◽  
Type Ii ◽  
Emotional Information ◽  
Major Depressive ◽  
Insula Cortex ◽  
Disorder Type ◽  
Ventral Prefrontal Cortex

BackgroundA significantly lower fractional anisotropy (FA) value has been shown in anterior parts of the corpus callosum in patients with bipolar disorder.AimsWe investigated the association between abnormal corpus callosum integrity and interhemispheric functional connectivity (IFC) in patients with bipolar disorder.MethodsWe examined the association between FA values in the corpus callosum (CC-FA) and the IFC between homotopic regions in the anterior cortical structures of bipolar disorder (n=16) and major depressive disorder (n=22) patients with depressed or euthymic states.ResultsWe found a positive correlation between the CC-FA and IFC values between homotopic regions of the ventral prefrontal cortex and insula cortex, and significantly lower IFC between these regions in bipolar disorder patients.ConclusionsThe abnormal corpus callosum integrity in bipolar disorder patients is relevant to the IFC between homotopic regions, possibly disturbing the exchange of emotional information between the cerebral hemispheres resulting in emotional dysregulation.

Neuroimaging effects of prenatal alcohol exposure on the developing human brain: a magnetic resonance imaging review

2015 ◽  
Vol 27 (5) ◽  
pp. 251-269 ◽  
Author(s):  
Kirsten Ann Donald ◽  
Emma Eastman ◽  
Fleur Margaret Howells ◽  
Colleen Adnams ◽  
Edward Patrick Riley ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Corpus Callosum ◽  
Human Brain ◽  
Grey Matter ◽  
Prenatal Alcohol Exposure ◽  
Alcohol Exposure ◽  
Resonance Imaging ◽  
Fetal Alcohol ◽  
Prenatal Alcohol

ObjectiveThis paper reviews the magnetic resonance imaging (MRI) literature on the effects of prenatal alcohol exposure on the developing human brain.MethodA literature search was conducted through the following databases: PubMed, PsycINFO and Google Scholar. Combinations of the following search terms and keywords were used to identify relevant studies: ‘alcohol’, ‘fetal alcohol spectrum disorders’, ‘fetal alcohol syndrome’, ‘FAS’, ‘FASD’, ‘MRI’, ‘DTI’, ‘MRS’, ‘neuroimaging’, ‘children’ and ‘infants’.ResultsA total of 64 relevant articles were identified across all modalities. Overall, studies reported smaller total brain volume as well as smaller volume of both the white and grey matter in specific cortical regions. The most consistently reported structural MRI findings were alterations in the shape and volume of the corpus callosum, as well as smaller volume in the basal ganglia and hippocampi. The most consistent finding from diffusion tensor imaging studies was lower fractional anisotropy in the corpus callosum. Proton magnetic resonance spectroscopy studies are few to date, but showed altered neurometabolic profiles in the frontal and parietal cortex, thalamus and dentate nuclei. Resting-state functional MRI studies reported reduced functional connectivity between cortical and deep grey matter structures.DiscussionThere is a critical gap in the literature of MRI studies in alcohol-exposed children under 5 years of age across all MRI modalities. The dynamic nature of brain maturation and appreciation of the effects of alcohol exposure on the developing trajectory of the structural and functional network argue for the prioritisation of studies that include a longitudinal approach to understanding this spectrum of effects and potential therapeutic time points.

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