Calcarine Fissure

Author(s):  
John E. Mendoza
Keyword(s):  
2019 ◽  
Vol 13 (2) ◽  
pp. 244-249
Author(s):  
Ricardo Nitrini ◽  
Leandro T. Lucato ◽  
Maria C. Sitta ◽  
Maíra O. Oliveira ◽  
Daniel Ciampi de Andrade ◽  
...  

ABSTRACT. The ability to repeat words is almost always preserved in thalamic aphasia. The pathophysiology of both thalamic aphasia and preservation of repetition are not fully understood. In a case of severe aphasia with preserved repetition after a left thalamic hemorrhage, MRI disclosed left thalamic lesion and loss of fractional anisotropy in the left centrum semiovale. FDG-PET showed severe hypometabolism in the left cerebral hemisphere, except for superior and transverse temporal gyri, calcarine fissure and frontopolar regions. Primary sensory function may be less functionally dependent on thalamic connections than heteromodal and paralimbic areas, which have connections with several thalamic nuclei. The extensive cortical hypometabolism due to diaschisis may have been responsible for the severity of the aphasia, whereas the less severe reduction of metabolism in the superior and transverse temporal gyri, and also, albeit less evident, in Broca’s area, might explain the preservation of repetition.


1902 ◽  
Vol 48 (202) ◽  
pp. 583-584
Author(s):  
William W. Ireland

Dr. Karl Schaffer, of Budapest, gives the results of his examination of the brains of three general paralytics. His paper is illustrated with five lithographs, showing sections of brain stained by Weigerts-Wolter's method. The degenerated parts take on the stain poorly. Schaffer finds the most degenerated parts in general paralysis to be the anterior and basal portions of the frontal lobes, the whole parietal lobes, the posterior median convolutions, the insula, and the temporal gyri, and the occipital lobes and the upper surface of the cerebellum. Less affected were the anterior median gyrus, the margins of the calcarine fissure, and the inferior occipito-gyri. This showed that degenerative process most affected the association centres of Flechsig, his sensory spheres being very much less touched. Schaffer holds that the degeneration of the cortex in general paralysis is not haphazard but selective. He upholds Flechsig's views, and considers that they have been confirmed by the recent researches of Ramon y Cajal, who has made an original study of the nerve-tissues in the foetus and in the newly-born child. The latter describes a specific plexus of centripetal nerve-fibres, which terminate in the motor area of the cortex, in the sphere of bodily sensibility, and in the visual area. It is significant that this plexus does not pass into Flechsig's association centres, confirming Schaffer's observation of the posterior median convolution being, in general paralysis, much more degenerated than the anterior. These considerations induce Schaffer to think that the posterior median gyrus belongs rather to the association centres than to the sensory areas.


1984 ◽  
Vol 61 (4) ◽  
pp. 767-771 ◽  
Author(s):  
Akira Hori ◽  
Attila Bardosi ◽  
Koji Tsuboi ◽  
Yutaka Maki

✓ Small separated accessory ventricles in the occipital lobe were observed in 21.3% of 404 patients, as seen by computerized tomogram. There was no significant preponderance in regard to sex or laterality. The accessory ventricles were clinically not significant. As seen at autopsy, accessory ventricles were found in the subcalcarine white matter, posterior to the occipital horn of the lateral ventricle, in 29.5% of 200 “normal” brains. Again, there were no significant sex and laterality differences. Accessory ventricles were never found in brains of fetuses or newborn babies. The youngest child in whom an accessory ventricle was found was 1 month old. No accessory ventricles were larger than 1 cm in diameter; they were slit-like, triangular or oval in shape. Histologically, they showed subtotal loss of the ependymal layer, subependymal gliosis, and/or fibrosis, and, in some cases, hyalinofibrotic capillary degeneration. Electron microscopy of the remaining ependymal cells in the accessory ventricle showed marked atrophy. Accessory ventricles are formed at the tip of the occipital horn postnatally through the expansion of the deep calcarine fissure, increase in brain volume in the region, and subsequent fusion of the mediolateral ventricular walls.


1978 ◽  
Vol 48 (4) ◽  
pp. 534-559 ◽  
Author(s):  
Arnold A. Zeal ◽  
Albert L. Rhoton

✓ In order to define the microsurgical anatomy, 50 posterior cerebral arteries (PCA's) were examined using × 3 to × 40 magnification. The PC A was divided into four segments: Pt was the segment proximal to the posterior communicating artery (PCoA); P2 extended from the PCoA to the posterior margin of the midbrain and was subdivided into an equal anterior (P2A) and posterior (P2P) half; P3 began at the posterior midbrain, ran within the quadrigeminal cistern, and ended at the anterior limit of the calcarine fissure. The PCA had three types of branches: 1) cortical branches to the cerebrum; 2) central branches to the brain stem; and 3) ventricular branches to the choroid plexus. The largest branches reaching the lateral surface of the cerebrum were located immediately anterior to the preoccipital notch, and in most cases were branches of the posterior temporal artery. This area offers a greater than 75% chance of finding a vessel large enough to perform a microvascular anastomosis. The central branches were of two types: 1) direct perforating, and 2) circumferential. The direct perforating branches arising on P1 were the posterior thalamoperforating arteries. The “thalamogeniculate artery,” the vessel said to be occluded in the “thalamic syndrome,” was also of the direct perforating type, but it was a series of small arteries arising from P2A and P2P rather than being a single vessel. The circumferential arteries usually arose from P1 and encircled the midbrain providing branches as far posteriorly as the colliculi. The branches to the choroid plexus were the medial and lateral posterior choroidal arteries; the former usually arose from P2A and entered the roof of the third ventricle, and the latter arose as a series of arteries from P2P and passed over the pulvinar to enter the lateral ventricle.


2017 ◽  
Vol 42 (3) ◽  
pp. 342-356 ◽  
Author(s):  
Zhichao Xia ◽  
Linjun Zhang ◽  
Fumiko Hoeft ◽  
Bin Gu ◽  
Gaolang Gong ◽  
...  

The ability to read is essential for cognitive development. To deepen our understanding of reading acquisition, we explored the neuroanatomical correlates (cortical thickness; CT) of word-reading fluency and sentence comprehension efficiency in Chinese with a group of typically developing children ( N = 21; 12 females and 9 males; age range 10.7–12.3 years). Then, we investigated the relationship between the CT of reading-defined regions and the cognitive subcomponents of reading to determine whether our study lends support to the multi-component model. The results demonstrated that children’s performance on oral word reading was positively correlated with CT in the left superior temporal gyrus (LSTG), left inferior temporal gyrus (LITG), left supramarginal gyrus (LSMG) and right superior temporal gyrus (RSTG). Moreover, CT in the LSTG, LSMG and LITG uniquely predicted children’s phonetic representation, phonological awareness, and orthography–phonology mapping skills, respectively. By contrast, children’s performance on sentence-reading comprehension was positively correlated with CT in the left parahippocampus (LPHP) and right calcarine fissure (RV1). As for the subcomponents of reading, CT in the LPHP was exclusively correlated with morphological awareness, whereas CT in the RV1 was correlated with orthography–semantic mapping. Taken together, these findings indicate that the reading network of typically developing children consists of multiple sub-divisions, thus providing neuroanatomical evidence in support of the multi-componential view of reading.


2021 ◽  
Vol 80 (5) ◽  
pp. 446-456
Author(s):  
Natalia Pérez-López ◽  
Carla Martín ◽  
Beatriz García ◽  
Maria Pilar Solís-Hernández ◽  
David Rodríguez ◽  
...  

Abstract The saccharide chains of heparan sulfate appear to be involved in several aspects Alzheimer disease (AD) pathogenesis. Their structural complexity is due to the expression of different isoenzymes. We studied the differential transcription of heparan sulfate chain biosynthesis in AD brains, analyzing different brain regions in patients with different extents of AD pathology. The transcriptomic study was performed by RT-PCR using samples of amygdala, anterior hippocampus, posterior hippocampus, claustrum, calcarine fissure, globus pallidus and cerebellum from patients with mild, moderate, or severe AD, as well as healthy individuals. Certain heparan sulfate epitopes were also detected by immunohistochemistry. Several genes, across all stages of heparan sulfate synthesis, showed altered transcription in different brain regions of AD patients. The numbers of alterations were greater in in moderate versus mild AD patients. In severe patients, there were fewer alterations in genes related to early stages of biosynthesis, and overexpression of genes involved in late stages. The alterations correlated with progressive brain atrophy, although alterations were more common in the cerebellum. Detection of some heparan sulfate epitopes by immunohistochemistry was consistent with previous studies. In conclusion, transcriptional alterations in the biosynthetic genes of heparan sulfate depend on the brain region and the degree of AD pathology.


Sign in / Sign up

Export Citation Format

Share Document