Comparative anatomy of dissected optic lobes, optic ventricles, midbrain tectum, collicular ventricles, and aqueduct: evolutionary modifications as potential explanation for non-tumoral aqueductal anomalies in humans
| Autor: | Gerald Conlogue, Sanjay Saluja, Vivek B. Kalra, E. Leon Kier, Cristopher G. Filippi |
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| Rok vydání: | 2021 |
| Předmět: |
Anatomy Comparative
Cerebral Ventricles Optic lobe Midbrain Dogs otorhinolaryngologic diseases medicine Animals Humans Mammals Tectum Mesencephali Nonmammalian business.industry Dissection Cerebral Aqueduct General Medicine Anatomy medicine.disease Anatomy Comparative Aqueductal stenosis Cerebral aqueduct Pediatrics Perinatology and Child Health Cerebral ventricle Original Article Cephalization Rabbits sense organs Neurology (clinical) Tectum Occipital lobe business Hydrocephalus |
| Zdroj: | Child's Nervous System |
| ISSN: | 1433-0350 0256-7040 |
| Popis: | Purpose An extensive literature has postulated multiple etiologies for aqueductal stenosis. No publications were found, discussing that evolutionary modifications might explain aqueductal anomalies. This study’s objectives were to review the evolutionary modifications of vertebrates’ tectum structures that might explain human aqueduct anomalies. Undertaking vertebrate comparative study is currently not feasible in view of limitations in obtaining vertebrate material. Thus, vertebrate material collected, injected, dissected, and radiographed in the early 1970s was analyzed, focusing on the aqueduct and components of the midbrain tectum. Methods Photographs of brain dissections and radiographs of the cerebral ventricles and arteries of adult shark, frog, iguana, rabbit, cat, dog, and primate specimens, containing a barium-gelatin radiopaque compound, were analyzed focusing on the aqueduct, the optic ventricles, the quadrigeminal plate, and collicular ventricles. The anatomic information provided by the dissections and radiographs is not reproducible by any other radiopaque contrast currently available. Results Dissected and radiographed cerebral ventricular and arterial systems of the vertebrates demonstrated midbrain tectum changes, including relative size modifications of the mammalian components of the tectum, simultaneously with the enlargement of the occipital lobe. There is a transformation of pre-mammalian optic ventricles to what appear to be collicular ventricles in mammals, as the aqueduct and collicular ventricle form a continuous cavity. Conclusions The mammalian tectum undergoes an evolutionary cephalization process consisting of relative size changes of the midbrain tectum structures. This is associated with enlargement of the occipital lobe, as part of overall neocortical expansion. Potentially, aqueductal anomalies could be explained by evolutionary modifications. |
| Databáze: | OpenAIRE |
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