The Effects of Normal Aging on Nerve Fibers and Neuroglia in the Central Nervous System
David R. Riddle in Brain Aging, 2007
The anterior commissure is another well-circumscribed bundle of white matter in which the total numbers of nerve fibers can be accurately determined [55]. In the anterior commissures of young monkeys, the mean number of nerve fibers is 2.2 × 106, while in monkeys over 25 years of age the mean number is reduced to 1.2 × 106. This loss of fibers is accompanied by a 25% reduction in the cross-sectional area of the anterior commissure. Some middle-aged monkeys, 12 to 20 years of age, also were available for study and it became evident that, in terms of the total numbers of nerve fibers, middle-aged monkeys resemble young ones, so most of the loss of nerve fibers appears to occur after middle age. Nerve fibers with abnormal myelin sheaths are evident at all ages, but there is a progressive, age-related increase in their frequency, such that in young monkeys only 0.4% of profiles of nerve fibers show alterations in myelin, while the number increases to 1.8% in middle-aged monkeys, and reaches 5.4% in old monkeys. Similarly, as would be expected from the loss of nerve fibers, there is a significant increase in the numbers of axons that show degenerative changes with age. Because most of the monkeys used in this study had been behaviorally tested, it was possible to correlate the data with a decline in their cognitive status. A positive correlation was found between the reduction in the total numbers of nerve fibers and cognitive impairment, but there was not a strong correlation between myelin sheath abnormalities and cognitive status.
Lesion Surgery for Parkinson's Disease: Practical Aspects of New Developments
Lucien Côté, Lola L. Sprinzeles, Robin Elliott, Austin H. Kutscher in Parkinson's Disease and Quality of Life, 2014
Although the goals of various surgeries are basically the same, the techniques used to achieve these goals vary significantly. The initial stage involves combining imaging with a frame secured to the patient's head. Early surgeries used ventriculography, which involved injection of dye into the ventricle (clear brain fluid) and then x-rays of the skull. Other techniques used the CAT scan alone or in combination with ventriculography. These approaches can allow accurate identification of two important internal landmarks in the brain, the anterior and posterior commissures. Atlases of the brain have been created in relation to these commissures. The relationship of various brain structures to the commissure varies somewhat between different individuals. The atlases would allow a close approximation of the target area once the location of the commissures is known precisely. The specific anatomy of any one particular patient is determined by using a macro-electrode for brain stimulation or micro-electrode for the monitoring of individual brain cell activity, as described above. Thus, imaging brings the electrode within several millimeters of the desired target and stimulation and recording techniques allow refinement of this to within less than 1 mm of the desired target.
Oral commissure burn
Alisa McQueen, S. Margaret Paik in Pediatric Emergency Medicine: Illustrated Clinical Cases, 2018
Oral burns caused by electrical trauma tend to occur during the teething period (3–36 months) from chewing on the female ends of live extension cords or exposed wires. Saliva acts as a medium to transport electrical current to the mucosa, causing intense heat and coagulation necrosis. Carefully inspect for burns, blisters, and charred skin, especially around the mouth. Destructive full thickness burns can extend to the tongue, floor of mouth, buccal mucosa, and labial vestibule. Edema and excessive drooling occurs within several hours. An eschar forms and later separates (1–3 weeks) with subsequent healing by secondary intention. An arterial hemorrhage can occur with eschar separation. Commissure injuries can lead to debilitating microstomia, which can affect speech, jaw and tongue movement, oral intake, oral hygiene, and cause facial distortion. Early reconstruction (commissuroplasty) and removable commissural splints are interventions to help prevent contractures.
Seizure and cognitive outcomes of posterior quadrantic disconnection: a series of 12 pediatric patients
Published in British Journal of Neurosurgery, 2020
Yao Wang, Chao Zhang, Xiu Wang, Lin Sang, Feng Zhou, Jian-Guo Zhang, Wen-Han Hu, Kai Zhang
After this procedure, the fibres mentioned in 1)–3) above were disconnected with remaining fibres as follows: 5) hippocampal efferent fibres; 6) projection fibres from the amygdala; 7) fibres through the anterior commissure between the anterior temporal lobe and limbic cortex; and 8) projection fibres from the insula to the basal ganglia, thalamus, hypothalamus and brain stem.(3) Stage III: Mesial temporal resection: After the opening of the temporal horn, the amygdala was revealed in the anteromedial part. The amygdala was removed along with resection of the subdural uncinate gyrus. The superior boundary of the amygdala resection was located at the top of the temporal horn of the lateral ventricle. The hippocampus was exposed and resected along the temporal horn and choroid fissure.
Surgical repair for transverse facial cleft: two flaps with a superiorly rotated single Z-plasty lateral to the commissure
Published in Journal of Plastic Surgery and Hand Surgery, 2019
Pan Zhou, Lin Qiu, Yan Liu, Tianwu Li, Xionghui Ding
In our research, we performed modified surgical techniques. The precise position of the new commissure is important. The anthropometric method before endotracheal intubation is necessary. Points A1 and A2 should be symmetrical to the non-cleft side commissure individually in theory, but we found that the labial length of the cleft side would be longer than the non-cleft side owing to complete contraction. Especially in hemifacial microsomia, the reconstructed commissure should be positioned slightly medially to provide balance to lesser facial tissue on the cleft side and the reconstructed commissural position [14]. Thus, we positioned A1 and A2 2 or 3 mm medial to the theoretical point individually. With vermillion-mucosal flaps, placement of the incisions in continuity with the commissures can be avoided and their positions can be stabilized [5]. We designed the triangular mucosa flap based on the inferior lip to hide the commissural scar in the superior moist lip and attain optimal cosmetic results. The rectangular vermilion-mucosa flap in the superior lip formed the oral mucosa of the buccal fissure. Thereby, the suture line could be made opposite the commissural triangular flap transfer direction. This geometric design increased the tensile strength when opening the mouth and can effectively prevent a postoperative acuminate commissure.
A novel SLC1A4 homozygous mutation causing congenital microcephaly, epileptic encephalopathy and spastic tetraparesis: a video-EEG and tractography – case study
Published in Journal of Neurogenetics, 2018
Erica Pironti, Vincenzo Salpietro, Francesca Cucinotta, Francesca Granata, Enricomaria Mormina, Stephanie Efthymiou, Carmela Scuderi, Antonella Gagliano, Henry Houlden, Gabriella Di Rosa
Baseline brain magnetic resonance imaging (MRI) was performed at three months of age. Morphological examination (Figure 2(A–C)) showed a diffuse, slight hyperintensity on T2-weighted images of biemispheric white matter, related to hypomyelination. Moreover, a severe hypoplasia of the corpus callosum was depicted, especially at trunk and splenium. The anterior commissure was present and enlarged, to compensate the lack of corpus callosum fibers. Tractographic evaluation was performed by diffusion tensor imaging (DTI) technique (Figure 3(A–E)). The study was targeted to anterior commissure evaluation. The compensatory enlargement of the anterior commissure was confirmed by DTI reconstruction (Figure 3(A–D)). Follow-up brain MRI examination was performed at four years. A significant hemispheric atrophy was depicted with involvement of both white and gray matter (Figure 2(D)). Moreover, brainstem atrophy was showed with enlargement of the cisternal spaces (Figure 2(E, F)).
Related Knowledge Centers
- Anterior Commissure
- Cerebral Hemisphere
- Corpus Callosum
- Decussation
- Nerve Tract
- Neural Pathway
- Posterior Commissure
- Commissural Fiber
- Longitudinal Fissure
- Anterior White Commissure